1994 YJ Help! Is the computer the problem
12-24-2005, 06:38 PM
#11
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
Thanks for the suggestion, but my problem is still there. I made it
11.4 miles this time.. I got some contact cleaner and grease. I
cleaned the contacts on every sensor I could find. In my search I
found a wire that the insulation had worn off, fixed that. I also
found the insulation on the coil lead of my new set of wires was warn
away in one spot. I am not sure just how this happened but it could
have been when the dealer or mechanic connect computer or timing light.
Mike Romain wrote:
> The 4.2 is a carburetor engine so you are going to get all kinds of
> wrong advise....
>
> You later state it is a 2.5.....
>
> I would be suspecting the electrical connections on the throttle body.
> When they get corroded, the gas pedal response can act like you
> describe.
>
> The pins are very small computer signal pins and can look perfectly
> clean but be corroded enough to interfere with the signal.
>
> I recommend a good clean of every sensor connection you can get your
> hands on with a spray contact cleaner. I then use dielectric grease on
> the plug's seal skirts. The best spray is sold at electronic shops, but
> in a pinch, WD40 will work as an electrical cleaner.
>
> I would try the clean before tossing any expensive parts at it.
>
> A massive vacuum leak at the TB is just plain -------- I am sorry to
> tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> they lied to you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> (More Off Road album links at bottom of the view page)
>
> aj wrote:
> >
> > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > has since been to the my local mechanic and the dealer. The problem
> > starts after 14 to 20 miles of driving. The engine starts running a
> > little rough just barely noticeable until you push in the clutch. Then
> > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > out the clutch and give it the gas its like driving into a very strong
> > head wind. If you push on most of the time the engine will surge a
> > couple of times and start running ok again. I have had the problem
> > show up both when the engine was cold but mostly it happens after
> > driving it a while. Once the problem occurs if you rev the engine from
> > idle it will backfire out the throttle body. The timing appears to be
> > advanced. There are no codes stored except the usual 12, 33 (I dont
> > have AC). I have listened to the injectors with a mechanics
> > stethoscope and they are all just clicking away.
> >
> > My mechanic thinks it's the computer, but from what I have read here
> > computers dont go bad very often. I brought it to the dealer for a
> > diagnostic they found a massive vacuum leak at the throttle body and
> > replaced. They also suggested the cat converter may be bad.
> >
> > The dealer said the compression was good and my mechanic said he
> > checked the grounds.
> >
> > I have replaced
> > Rotor
> > Distrib Cap
> > Plug Wires
> > Coil
> > Plugs
> > Radiator (it needed it lots of fins were gone)
> > Coolant Temperature Sensor
> > Vehicle Speed Sensor
> > Throttle body
> > Cat Converter
> > Oil
> > Oil Filter
> > I have also added a bottle of fuel injector cleaner in the gas.
> >
> > When its not acting up it runs like a dream, all kinds of power,
> > well at least for a 4.2L. I really dont want to replace this one I just
> > got it setup the way I wanted it.
> >
> > The computer is next.
> >
> > Does anyone have any ideas.
11.4 miles this time.. I got some contact cleaner and grease. I
cleaned the contacts on every sensor I could find. In my search I
found a wire that the insulation had worn off, fixed that. I also
found the insulation on the coil lead of my new set of wires was warn
away in one spot. I am not sure just how this happened but it could
have been when the dealer or mechanic connect computer or timing light.
Mike Romain wrote:
> The 4.2 is a carburetor engine so you are going to get all kinds of
> wrong advise....
>
> You later state it is a 2.5.....
>
> I would be suspecting the electrical connections on the throttle body.
> When they get corroded, the gas pedal response can act like you
> describe.
>
> The pins are very small computer signal pins and can look perfectly
> clean but be corroded enough to interfere with the signal.
>
> I recommend a good clean of every sensor connection you can get your
> hands on with a spray contact cleaner. I then use dielectric grease on
> the plug's seal skirts. The best spray is sold at electronic shops, but
> in a pinch, WD40 will work as an electrical cleaner.
>
> I would try the clean before tossing any expensive parts at it.
>
> A massive vacuum leak at the TB is just plain -------- I am sorry to
> tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> they lied to you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> (More Off Road album links at bottom of the view page)
>
> aj wrote:
> >
> > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > has since been to the my local mechanic and the dealer. The problem
> > starts after 14 to 20 miles of driving. The engine starts running a
> > little rough just barely noticeable until you push in the clutch. Then
> > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > out the clutch and give it the gas its like driving into a very strong
> > head wind. If you push on most of the time the engine will surge a
> > couple of times and start running ok again. I have had the problem
> > show up both when the engine was cold but mostly it happens after
> > driving it a while. Once the problem occurs if you rev the engine from
> > idle it will backfire out the throttle body. The timing appears to be
> > advanced. There are no codes stored except the usual 12, 33 (I dont
> > have AC). I have listened to the injectors with a mechanics
> > stethoscope and they are all just clicking away.
> >
> > My mechanic thinks it's the computer, but from what I have read here
> > computers dont go bad very often. I brought it to the dealer for a
> > diagnostic they found a massive vacuum leak at the throttle body and
> > replaced. They also suggested the cat converter may be bad.
> >
> > The dealer said the compression was good and my mechanic said he
> > checked the grounds.
> >
> > I have replaced
> > Rotor
> > Distrib Cap
> > Plug Wires
> > Coil
> > Plugs
> > Radiator (it needed it lots of fins were gone)
> > Coolant Temperature Sensor
> > Vehicle Speed Sensor
> > Throttle body
> > Cat Converter
> > Oil
> > Oil Filter
> > I have also added a bottle of fuel injector cleaner in the gas.
> >
> > When its not acting up it runs like a dream, all kinds of power,
> > well at least for a 4.2L. I really dont want to replace this one I just
> > got it setup the way I wanted it.
> >
> > The computer is next.
> >
> > Does anyone have any ideas.
12-24-2005, 06:38 PM
#12
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
Thanks for the suggestion, but my problem is still there. I made it
11.4 miles this time.. I got some contact cleaner and grease. I
cleaned the contacts on every sensor I could find. In my search I
found a wire that the insulation had worn off, fixed that. I also
found the insulation on the coil lead of my new set of wires was warn
away in one spot. I am not sure just how this happened but it could
have been when the dealer or mechanic connect computer or timing light.
Mike Romain wrote:
> The 4.2 is a carburetor engine so you are going to get all kinds of
> wrong advise....
>
> You later state it is a 2.5.....
>
> I would be suspecting the electrical connections on the throttle body.
> When they get corroded, the gas pedal response can act like you
> describe.
>
> The pins are very small computer signal pins and can look perfectly
> clean but be corroded enough to interfere with the signal.
>
> I recommend a good clean of every sensor connection you can get your
> hands on with a spray contact cleaner. I then use dielectric grease on
> the plug's seal skirts. The best spray is sold at electronic shops, but
> in a pinch, WD40 will work as an electrical cleaner.
>
> I would try the clean before tossing any expensive parts at it.
>
> A massive vacuum leak at the TB is just plain -------- I am sorry to
> tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> they lied to you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> (More Off Road album links at bottom of the view page)
>
> aj wrote:
> >
> > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > has since been to the my local mechanic and the dealer. The problem
> > starts after 14 to 20 miles of driving. The engine starts running a
> > little rough just barely noticeable until you push in the clutch. Then
> > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > out the clutch and give it the gas its like driving into a very strong
> > head wind. If you push on most of the time the engine will surge a
> > couple of times and start running ok again. I have had the problem
> > show up both when the engine was cold but mostly it happens after
> > driving it a while. Once the problem occurs if you rev the engine from
> > idle it will backfire out the throttle body. The timing appears to be
> > advanced. There are no codes stored except the usual 12, 33 (I dont
> > have AC). I have listened to the injectors with a mechanics
> > stethoscope and they are all just clicking away.
> >
> > My mechanic thinks it's the computer, but from what I have read here
> > computers dont go bad very often. I brought it to the dealer for a
> > diagnostic they found a massive vacuum leak at the throttle body and
> > replaced. They also suggested the cat converter may be bad.
> >
> > The dealer said the compression was good and my mechanic said he
> > checked the grounds.
> >
> > I have replaced
> > Rotor
> > Distrib Cap
> > Plug Wires
> > Coil
> > Plugs
> > Radiator (it needed it lots of fins were gone)
> > Coolant Temperature Sensor
> > Vehicle Speed Sensor
> > Throttle body
> > Cat Converter
> > Oil
> > Oil Filter
> > I have also added a bottle of fuel injector cleaner in the gas.
> >
> > When its not acting up it runs like a dream, all kinds of power,
> > well at least for a 4.2L. I really dont want to replace this one I just
> > got it setup the way I wanted it.
> >
> > The computer is next.
> >
> > Does anyone have any ideas.
11.4 miles this time.. I got some contact cleaner and grease. I
cleaned the contacts on every sensor I could find. In my search I
found a wire that the insulation had worn off, fixed that. I also
found the insulation on the coil lead of my new set of wires was warn
away in one spot. I am not sure just how this happened but it could
have been when the dealer or mechanic connect computer or timing light.
Mike Romain wrote:
> The 4.2 is a carburetor engine so you are going to get all kinds of
> wrong advise....
>
> You later state it is a 2.5.....
>
> I would be suspecting the electrical connections on the throttle body.
> When they get corroded, the gas pedal response can act like you
> describe.
>
> The pins are very small computer signal pins and can look perfectly
> clean but be corroded enough to interfere with the signal.
>
> I recommend a good clean of every sensor connection you can get your
> hands on with a spray contact cleaner. I then use dielectric grease on
> the plug's seal skirts. The best spray is sold at electronic shops, but
> in a pinch, WD40 will work as an electrical cleaner.
>
> I would try the clean before tossing any expensive parts at it.
>
> A massive vacuum leak at the TB is just plain -------- I am sorry to
> tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> they lied to you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> (More Off Road album links at bottom of the view page)
>
> aj wrote:
> >
> > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > has since been to the my local mechanic and the dealer. The problem
> > starts after 14 to 20 miles of driving. The engine starts running a
> > little rough just barely noticeable until you push in the clutch. Then
> > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > out the clutch and give it the gas its like driving into a very strong
> > head wind. If you push on most of the time the engine will surge a
> > couple of times and start running ok again. I have had the problem
> > show up both when the engine was cold but mostly it happens after
> > driving it a while. Once the problem occurs if you rev the engine from
> > idle it will backfire out the throttle body. The timing appears to be
> > advanced. There are no codes stored except the usual 12, 33 (I dont
> > have AC). I have listened to the injectors with a mechanics
> > stethoscope and they are all just clicking away.
> >
> > My mechanic thinks it's the computer, but from what I have read here
> > computers dont go bad very often. I brought it to the dealer for a
> > diagnostic they found a massive vacuum leak at the throttle body and
> > replaced. They also suggested the cat converter may be bad.
> >
> > The dealer said the compression was good and my mechanic said he
> > checked the grounds.
> >
> > I have replaced
> > Rotor
> > Distrib Cap
> > Plug Wires
> > Coil
> > Plugs
> > Radiator (it needed it lots of fins were gone)
> > Coolant Temperature Sensor
> > Vehicle Speed Sensor
> > Throttle body
> > Cat Converter
> > Oil
> > Oil Filter
> > I have also added a bottle of fuel injector cleaner in the gas.
> >
> > When its not acting up it runs like a dream, all kinds of power,
> > well at least for a 4.2L. I really dont want to replace this one I just
> > got it setup the way I wanted it.
> >
> > The computer is next.
> >
> > Does anyone have any ideas.
12-24-2005, 06:38 PM
#13
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
Thanks for the suggestion, but my problem is still there. I made it
11.4 miles this time.. I got some contact cleaner and grease. I
cleaned the contacts on every sensor I could find. In my search I
found a wire that the insulation had worn off, fixed that. I also
found the insulation on the coil lead of my new set of wires was warn
away in one spot. I am not sure just how this happened but it could
have been when the dealer or mechanic connect computer or timing light.
Mike Romain wrote:
> The 4.2 is a carburetor engine so you are going to get all kinds of
> wrong advise....
>
> You later state it is a 2.5.....
>
> I would be suspecting the electrical connections on the throttle body.
> When they get corroded, the gas pedal response can act like you
> describe.
>
> The pins are very small computer signal pins and can look perfectly
> clean but be corroded enough to interfere with the signal.
>
> I recommend a good clean of every sensor connection you can get your
> hands on with a spray contact cleaner. I then use dielectric grease on
> the plug's seal skirts. The best spray is sold at electronic shops, but
> in a pinch, WD40 will work as an electrical cleaner.
>
> I would try the clean before tossing any expensive parts at it.
>
> A massive vacuum leak at the TB is just plain -------- I am sorry to
> tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> they lied to you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> (More Off Road album links at bottom of the view page)
>
> aj wrote:
> >
> > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > has since been to the my local mechanic and the dealer. The problem
> > starts after 14 to 20 miles of driving. The engine starts running a
> > little rough just barely noticeable until you push in the clutch. Then
> > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > out the clutch and give it the gas its like driving into a very strong
> > head wind. If you push on most of the time the engine will surge a
> > couple of times and start running ok again. I have had the problem
> > show up both when the engine was cold but mostly it happens after
> > driving it a while. Once the problem occurs if you rev the engine from
> > idle it will backfire out the throttle body. The timing appears to be
> > advanced. There are no codes stored except the usual 12, 33 (I dont
> > have AC). I have listened to the injectors with a mechanics
> > stethoscope and they are all just clicking away.
> >
> > My mechanic thinks it's the computer, but from what I have read here
> > computers dont go bad very often. I brought it to the dealer for a
> > diagnostic they found a massive vacuum leak at the throttle body and
> > replaced. They also suggested the cat converter may be bad.
> >
> > The dealer said the compression was good and my mechanic said he
> > checked the grounds.
> >
> > I have replaced
> > Rotor
> > Distrib Cap
> > Plug Wires
> > Coil
> > Plugs
> > Radiator (it needed it lots of fins were gone)
> > Coolant Temperature Sensor
> > Vehicle Speed Sensor
> > Throttle body
> > Cat Converter
> > Oil
> > Oil Filter
> > I have also added a bottle of fuel injector cleaner in the gas.
> >
> > When its not acting up it runs like a dream, all kinds of power,
> > well at least for a 4.2L. I really dont want to replace this one I just
> > got it setup the way I wanted it.
> >
> > The computer is next.
> >
> > Does anyone have any ideas.
11.4 miles this time.. I got some contact cleaner and grease. I
cleaned the contacts on every sensor I could find. In my search I
found a wire that the insulation had worn off, fixed that. I also
found the insulation on the coil lead of my new set of wires was warn
away in one spot. I am not sure just how this happened but it could
have been when the dealer or mechanic connect computer or timing light.
Mike Romain wrote:
> The 4.2 is a carburetor engine so you are going to get all kinds of
> wrong advise....
>
> You later state it is a 2.5.....
>
> I would be suspecting the electrical connections on the throttle body.
> When they get corroded, the gas pedal response can act like you
> describe.
>
> The pins are very small computer signal pins and can look perfectly
> clean but be corroded enough to interfere with the signal.
>
> I recommend a good clean of every sensor connection you can get your
> hands on with a spray contact cleaner. I then use dielectric grease on
> the plug's seal skirts. The best spray is sold at electronic shops, but
> in a pinch, WD40 will work as an electrical cleaner.
>
> I would try the clean before tossing any expensive parts at it.
>
> A massive vacuum leak at the TB is just plain -------- I am sorry to
> tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> they lied to you.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
> Canadian Off Road Trips Photos: Non members can still view!
> Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> (More Off Road album links at bottom of the view page)
>
> aj wrote:
> >
> > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > has since been to the my local mechanic and the dealer. The problem
> > starts after 14 to 20 miles of driving. The engine starts running a
> > little rough just barely noticeable until you push in the clutch. Then
> > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > out the clutch and give it the gas its like driving into a very strong
> > head wind. If you push on most of the time the engine will surge a
> > couple of times and start running ok again. I have had the problem
> > show up both when the engine was cold but mostly it happens after
> > driving it a while. Once the problem occurs if you rev the engine from
> > idle it will backfire out the throttle body. The timing appears to be
> > advanced. There are no codes stored except the usual 12, 33 (I dont
> > have AC). I have listened to the injectors with a mechanics
> > stethoscope and they are all just clicking away.
> >
> > My mechanic thinks it's the computer, but from what I have read here
> > computers dont go bad very often. I brought it to the dealer for a
> > diagnostic they found a massive vacuum leak at the throttle body and
> > replaced. They also suggested the cat converter may be bad.
> >
> > The dealer said the compression was good and my mechanic said he
> > checked the grounds.
> >
> > I have replaced
> > Rotor
> > Distrib Cap
> > Plug Wires
> > Coil
> > Plugs
> > Radiator (it needed it lots of fins were gone)
> > Coolant Temperature Sensor
> > Vehicle Speed Sensor
> > Throttle body
> > Cat Converter
> > Oil
> > Oil Filter
> > I have also added a bottle of fuel injector cleaner in the gas.
> >
> > When its not acting up it runs like a dream, all kinds of power,
> > well at least for a 4.2L. I really dont want to replace this one I just
> > got it setup the way I wanted it.
> >
> > The computer is next.
> >
> > Does anyone have any ideas.
12-24-2005, 06:49 PM
#14
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
You did replace the Crank Position Sensor, right?
http://www.off-road.com/jeep/cheroke...tdcsensor.html
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
http://www.off-road.com/jeep/cheroke...tdcsensor.html
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
12-24-2005, 06:49 PM
#15
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
You did replace the Crank Position Sensor, right?
http://www.off-road.com/jeep/cheroke...tdcsensor.html
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
http://www.off-road.com/jeep/cheroke...tdcsensor.html
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
12-24-2005, 06:49 PM
#16
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
You did replace the Crank Position Sensor, right?
http://www.off-road.com/jeep/cheroke...tdcsensor.html
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
http://www.off-road.com/jeep/cheroke...tdcsensor.html
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
12-24-2005, 07:13 PM
#17
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
In article <1135467496.595567.136690@g14g2000cwa.googlegroups .com>,
aj <ajleduc@msn.com> wrote:
>Thanks for the suggestion, but my problem is still there. I made it
>11.4 miles this time.. I got some contact cleaner and grease. I
>cleaned the contacts on every sensor I could find. In my search I
>found a wire that the insulation had worn off, fixed that. I also
>found the insulation on the coil lead of my new set of wires was warn
>away in one spot. I am not sure just how this happened but it could
>have been when the dealer or mechanic connect computer or timing light.
Did you have your fuel pressure tested yet???
When you first start the engine, it will run fine but after 10 or 15 miles
your fuel pump might be loosing fuel pressure. I would put a guage inline
and drive around. Check it cold and after 10-15 miles.
--
Jeeps and dubs and everything's nice...
aj <ajleduc@msn.com> wrote:
>Thanks for the suggestion, but my problem is still there. I made it
>11.4 miles this time.. I got some contact cleaner and grease. I
>cleaned the contacts on every sensor I could find. In my search I
>found a wire that the insulation had worn off, fixed that. I also
>found the insulation on the coil lead of my new set of wires was warn
>away in one spot. I am not sure just how this happened but it could
>have been when the dealer or mechanic connect computer or timing light.
Did you have your fuel pressure tested yet???
When you first start the engine, it will run fine but after 10 or 15 miles
your fuel pump might be loosing fuel pressure. I would put a guage inline
and drive around. Check it cold and after 10-15 miles.
--
Jeeps and dubs and everything's nice...
12-24-2005, 07:13 PM
#18
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
In article <1135467496.595567.136690@g14g2000cwa.googlegroups .com>,
aj <ajleduc@msn.com> wrote:
>Thanks for the suggestion, but my problem is still there. I made it
>11.4 miles this time.. I got some contact cleaner and grease. I
>cleaned the contacts on every sensor I could find. In my search I
>found a wire that the insulation had worn off, fixed that. I also
>found the insulation on the coil lead of my new set of wires was warn
>away in one spot. I am not sure just how this happened but it could
>have been when the dealer or mechanic connect computer or timing light.
Did you have your fuel pressure tested yet???
When you first start the engine, it will run fine but after 10 or 15 miles
your fuel pump might be loosing fuel pressure. I would put a guage inline
and drive around. Check it cold and after 10-15 miles.
--
Jeeps and dubs and everything's nice...
aj <ajleduc@msn.com> wrote:
>Thanks for the suggestion, but my problem is still there. I made it
>11.4 miles this time.. I got some contact cleaner and grease. I
>cleaned the contacts on every sensor I could find. In my search I
>found a wire that the insulation had worn off, fixed that. I also
>found the insulation on the coil lead of my new set of wires was warn
>away in one spot. I am not sure just how this happened but it could
>have been when the dealer or mechanic connect computer or timing light.
Did you have your fuel pressure tested yet???
When you first start the engine, it will run fine but after 10 or 15 miles
your fuel pump might be loosing fuel pressure. I would put a guage inline
and drive around. Check it cold and after 10-15 miles.
--
Jeeps and dubs and everything's nice...
12-24-2005, 07:13 PM
#19
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
In article <1135467496.595567.136690@g14g2000cwa.googlegroups .com>,
aj <ajleduc@msn.com> wrote:
>Thanks for the suggestion, but my problem is still there. I made it
>11.4 miles this time.. I got some contact cleaner and grease. I
>cleaned the contacts on every sensor I could find. In my search I
>found a wire that the insulation had worn off, fixed that. I also
>found the insulation on the coil lead of my new set of wires was warn
>away in one spot. I am not sure just how this happened but it could
>have been when the dealer or mechanic connect computer or timing light.
Did you have your fuel pressure tested yet???
When you first start the engine, it will run fine but after 10 or 15 miles
your fuel pump might be loosing fuel pressure. I would put a guage inline
and drive around. Check it cold and after 10-15 miles.
--
Jeeps and dubs and everything's nice...
aj <ajleduc@msn.com> wrote:
>Thanks for the suggestion, but my problem is still there. I made it
>11.4 miles this time.. I got some contact cleaner and grease. I
>cleaned the contacts on every sensor I could find. In my search I
>found a wire that the insulation had worn off, fixed that. I also
>found the insulation on the coil lead of my new set of wires was warn
>away in one spot. I am not sure just how this happened but it could
>have been when the dealer or mechanic connect computer or timing light.
Did you have your fuel pressure tested yet???
When you first start the engine, it will run fine but after 10 or 15 miles
your fuel pump might be loosing fuel pressure. I would put a guage inline
and drive around. Check it cold and after 10-15 miles.
--
Jeeps and dubs and everything's nice...
12-24-2005, 07:14 PM
#20
Guest
Posts: n/a
Re: 1994 YJ Help! Is the computer the problem
How about the gas tank vent on those? That would be the charcoal
canister... If you open the gas cap and it goes whoosh and then it runs
ok again, the air filter on the gas tank vent is plugged up with mud or
dirt or just too old.
On a 94... Gas filter? Does it have one on the frame rail just in front
of the tank? If so, I would change that too....
Worn away new HT wires, as in pleural!!!!! Say what????????
That just plain isn't supposed to happen. Ever. Something is seriously
wrong with those wires....
If the core was exposed on the coil wire or any other, they are dead
wires and need to be replaced. If the insulation is falling off, it
didn't cure or was a bad mix or something.
I would just plain take those wires back and get new ones. That could
be all your latest issues.
Mike
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
>
> Mike Romain wrote:
> > The 4.2 is a carburetor engine so you are going to get all kinds of
> > wrong advise....
> >
> > You later state it is a 2.5.....
> >
> > I would be suspecting the electrical connections on the throttle body.
> > When they get corroded, the gas pedal response can act like you
> > describe.
> >
> > The pins are very small computer signal pins and can look perfectly
> > clean but be corroded enough to interfere with the signal.
> >
> > I recommend a good clean of every sensor connection you can get your
> > hands on with a spray contact cleaner. I then use dielectric grease on
> > the plug's seal skirts. The best spray is sold at electronic shops, but
> > in a pinch, WD40 will work as an electrical cleaner.
> >
> > I would try the clean before tossing any expensive parts at it.
> >
> > A massive vacuum leak at the TB is just plain -------- I am sorry to
> > tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> > they lied to you.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> > Canadian Off Road Trips Photos: Non members can still view!
> > Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> > (More Off Road album links at bottom of the view page)
> >
> > aj wrote:
> > >
> > > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > > has since been to the my local mechanic and the dealer. The problem
> > > starts after 14 to 20 miles of driving. The engine starts running a
> > > little rough just barely noticeable until you push in the clutch. Then
> > > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > > out the clutch and give it the gas its like driving into a very strong
> > > head wind. If you push on most of the time the engine will surge a
> > > couple of times and start running ok again. I have had the problem
> > > show up both when the engine was cold but mostly it happens after
> > > driving it a while. Once the problem occurs if you rev the engine from
> > > idle it will backfire out the throttle body. The timing appears to be
> > > advanced. There are no codes stored except the usual 12, 33 (I dont
> > > have AC). I have listened to the injectors with a mechanics
> > > stethoscope and they are all just clicking away.
> > >
> > > My mechanic thinks it's the computer, but from what I have read here
> > > computers dont go bad very often. I brought it to the dealer for a
> > > diagnostic they found a massive vacuum leak at the throttle body and
> > > replaced. They also suggested the cat converter may be bad.
> > >
> > > The dealer said the compression was good and my mechanic said he
> > > checked the grounds.
> > >
> > > I have replaced
> > > Rotor
> > > Distrib Cap
> > > Plug Wires
> > > Coil
> > > Plugs
> > > Radiator (it needed it lots of fins were gone)
> > > Coolant Temperature Sensor
> > > Vehicle Speed Sensor
> > > Throttle body
> > > Cat Converter
> > > Oil
> > > Oil Filter
> > > I have also added a bottle of fuel injector cleaner in the gas.
> > >
> > > When its not acting up it runs like a dream, all kinds of power,
> > > well at least for a 4.2L. I really dont want to replace this one I just
> > > got it setup the way I wanted it.
> > >
> > > The computer is next.
> > >
> > > Does anyone have any ideas.
canister... If you open the gas cap and it goes whoosh and then it runs
ok again, the air filter on the gas tank vent is plugged up with mud or
dirt or just too old.
On a 94... Gas filter? Does it have one on the frame rail just in front
of the tank? If so, I would change that too....
Worn away new HT wires, as in pleural!!!!! Say what????????
That just plain isn't supposed to happen. Ever. Something is seriously
wrong with those wires....
If the core was exposed on the coil wire or any other, they are dead
wires and need to be replaced. If the insulation is falling off, it
didn't cure or was a bad mix or something.
I would just plain take those wires back and get new ones. That could
be all your latest issues.
Mike
aj wrote:
>
> Thanks for the suggestion, but my problem is still there. I made it
> 11.4 miles this time.. I got some contact cleaner and grease. I
> cleaned the contacts on every sensor I could find. In my search I
> found a wire that the insulation had worn off, fixed that. I also
> found the insulation on the coil lead of my new set of wires was warn
> away in one spot. I am not sure just how this happened but it could
> have been when the dealer or mechanic connect computer or timing light.
>
> Mike Romain wrote:
> > The 4.2 is a carburetor engine so you are going to get all kinds of
> > wrong advise....
> >
> > You later state it is a 2.5.....
> >
> > I would be suspecting the electrical connections on the throttle body.
> > When they get corroded, the gas pedal response can act like you
> > describe.
> >
> > The pins are very small computer signal pins and can look perfectly
> > clean but be corroded enough to interfere with the signal.
> >
> > I recommend a good clean of every sensor connection you can get your
> > hands on with a spray contact cleaner. I then use dielectric grease on
> > the plug's seal skirts. The best spray is sold at electronic shops, but
> > in a pinch, WD40 will work as an electrical cleaner.
> >
> > I would try the clean before tossing any expensive parts at it.
> >
> > A massive vacuum leak at the TB is just plain -------- I am sorry to
> > tell you. A vacuum leak at the TB causes 'high' idle, not low idle,
> > they lied to you.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> > Canadian Off Road Trips Photos: Non members can still view!
> > Aug./05 http://www.imagestation.com/album/in...?id=2120343242
> > (More Off Road album links at bottom of the view page)
> >
> > aj wrote:
> > >
> > > My 94 YJ 4.2L MPFI, 104000 miles started acting up a few weeks ago. It
> > > has since been to the my local mechanic and the dealer. The problem
> > > starts after 14 to 20 miles of driving. The engine starts running a
> > > little rough just barely noticeable until you push in the clutch. Then
> > > the idle drops off very quickly to about 200 to 300 rpm. When you let
> > > out the clutch and give it the gas its like driving into a very strong
> > > head wind. If you push on most of the time the engine will surge a
> > > couple of times and start running ok again. I have had the problem
> > > show up both when the engine was cold but mostly it happens after
> > > driving it a while. Once the problem occurs if you rev the engine from
> > > idle it will backfire out the throttle body. The timing appears to be
> > > advanced. There are no codes stored except the usual 12, 33 (I dont
> > > have AC). I have listened to the injectors with a mechanics
> > > stethoscope and they are all just clicking away.
> > >
> > > My mechanic thinks it's the computer, but from what I have read here
> > > computers dont go bad very often. I brought it to the dealer for a
> > > diagnostic they found a massive vacuum leak at the throttle body and
> > > replaced. They also suggested the cat converter may be bad.
> > >
> > > The dealer said the compression was good and my mechanic said he
> > > checked the grounds.
> > >
> > > I have replaced
> > > Rotor
> > > Distrib Cap
> > > Plug Wires
> > > Coil
> > > Plugs
> > > Radiator (it needed it lots of fins were gone)
> > > Coolant Temperature Sensor
> > > Vehicle Speed Sensor
> > > Throttle body
> > > Cat Converter
> > > Oil
> > > Oil Filter
> > > I have also added a bottle of fuel injector cleaner in the gas.
> > >
> > > When its not acting up it runs like a dream, all kinds of power,
> > > well at least for a 4.2L. I really dont want to replace this one I just
> > > got it setup the way I wanted it.
> > >
> > > The computer is next.
> > >
> > > Does anyone have any ideas.