Stephen Cowell

"reigelser" <reigelser@sbcglobal.net> wrote in message news:Dipre.429$on5.195@newssvr19.news.prodigy.com. ..
> It is an automatic transmission. What is the wiper return voltage? The other
> voltage I can measure on the TPS besides the ~200mV to ~4V?
> I check the message with an OBD Reader. P0123 I think is the number or
> P0124, don't remember right now. Are you referring to the Check Engine Light
> flashing when you mension a 24 and a 15?

Yes... too cheap to get the OBD. '124' would correspond to
the '24'... TPS.

Start thinking about things like the ground wire
between the engine and the firewall.. this is a
known problem point. Doug has the right
idea... make sure all connections are clean
and tight.

Problem starting... to start an EFI vehicle, you
should keep your foot *off* the gas until the
vehicle has started... no need to touch the
gas until you take off. You're doing this,
right?

Has other maintenance been done recently?
Does the engine run smooth once it starts?
Describe what you have to do to get it
to start (i.e. grind long, grind twice, feather
throttle, etc.).

The TPS is basically a potentiometer, with three
wires going to it... supply, wiper, and ground. The supply
is a regulated voltage, sent by the computer and used
by the computer as a reference. If this is moving around,
the computer may have unfixable problems (blown regulator
pass transistor, etc.) or another sensor or connection may be
screwing up your TPS reading. The wiper voltage is the one that
changes as the throttle plate opens and closes... it should
track the position of the gas pedal steadily. The wiper
carries your 200mV to 4V.
__
Steve
..

Jerry Bransford

That may be but I would still place the ECU at the dead-end of any list
of likely culprits. :)

reigelser wrote:
> I replaced it allready and all voltages are fine in all ranges of motion of
> the TPS. I also tried to disable other parts of the electric system to see
> if there is an effect on the tps circuit, without success. The error won't
> clear and there is still an effect on the driving behavior.
> "Jerry Bransford" <jerrypb@***.net> wrote in message
> news:kAore.88$X71.85@fed1read07...
>
>>The TJ's ECU is known to be extremely reliable and just about
>>trouble-free. Have you already replaced the TPS and cleaned/reseated the
>>electrical connection that connects the ECU to the TPS? Bad TPSs are
>>easily replaced and far cheaper than replacing the ECU.
>>
>>Jerry
>>
>>reigelser wrote:
>>
>>>I need the ECU eventually because of a persistent TPS error. My mechanic
>>>troubleshooted it and thinks its probably the ECU. But he thinks there
>>>has to be some reprogramming to be done, because I tried one from the
>>>junk yard before he looked into it and nothing changed (same TPS error,
>>>same mileage). It's a 97 inline 6 Cherokee. It works, but it doesn't
>>>start at first try and it is not very smooth if you want to accelerate
>>>from 65 to 75 without a kickdown.
>>>
>>>"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
>>>news:JQXqe.18$kX4.14@newssvr30.news.prodigy.com ...
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:42ABA761.F70549FF@cac.net...
>>>
>>>
>>>>depends on the year starting in 04 all pcm,s are shipped with out
>>>>software and
>>>>it has to progammed by vin
>>>>now more salvage yard pcm swapping
>>>
>>>^^^^^^^
>>>
>>>One letter... how it changes things.
>>>Tim probably meant 'no'...
>>>__
>>>Steve
>>>.
>>>
>>>
>>>
>>>
>>>
>>>
>>>>reigelser wrote:
>>>>
>>>>
>>>>
>>>>>Hi,
>>>>>does anybody know, if there is some programming or calibration to be
>>>>>done if
>>>>>the engine control unit is replaced? Or do I just plug it in and thats
>>>>>it?
>>>>>Thanks for the advice.
>>>>>
>>>>>Jo
>>>>
>>>
>>--
>>Jerry Bransford
>>PP-ASEL N6TAY
>>See the Geezer Jeep at
>>http://members.***.net/jerrypb/
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

Jerry Bransford

That may be but I would still place the ECU at the dead-end of any list
of likely culprits. :)

reigelser wrote:
> I replaced it allready and all voltages are fine in all ranges of motion of
> the TPS. I also tried to disable other parts of the electric system to see
> if there is an effect on the tps circuit, without success. The error won't
> clear and there is still an effect on the driving behavior.
> "Jerry Bransford" <jerrypb@***.net> wrote in message
> news:kAore.88$X71.85@fed1read07...
>
>>The TJ's ECU is known to be extremely reliable and just about
>>trouble-free. Have you already replaced the TPS and cleaned/reseated the
>>electrical connection that connects the ECU to the TPS? Bad TPSs are
>>easily replaced and far cheaper than replacing the ECU.
>>
>>Jerry
>>
>>reigelser wrote:
>>
>>>I need the ECU eventually because of a persistent TPS error. My mechanic
>>>troubleshooted it and thinks its probably the ECU. But he thinks there
>>>has to be some reprogramming to be done, because I tried one from the
>>>junk yard before he looked into it and nothing changed (same TPS error,
>>>same mileage). It's a 97 inline 6 Cherokee. It works, but it doesn't
>>>start at first try and it is not very smooth if you want to accelerate
>>>from 65 to 75 without a kickdown.
>>>
>>>"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
>>>news:JQXqe.18$kX4.14@newssvr30.news.prodigy.com ...
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:42ABA761.F70549FF@cac.net...
>>>
>>>
>>>>depends on the year starting in 04 all pcm,s are shipped with out
>>>>software and
>>>>it has to progammed by vin
>>>>now more salvage yard pcm swapping
>>>
>>>^^^^^^^
>>>
>>>One letter... how it changes things.
>>>Tim probably meant 'no'...
>>>__
>>>Steve
>>>.
>>>
>>>
>>>
>>>
>>>
>>>
>>>>reigelser wrote:
>>>>
>>>>
>>>>
>>>>>Hi,
>>>>>does anybody know, if there is some programming or calibration to be
>>>>>done if
>>>>>the engine control unit is replaced? Or do I just plug it in and thats
>>>>>it?
>>>>>Thanks for the advice.
>>>>>
>>>>>Jo
>>>>
>>>
>>--
>>Jerry Bransford
>>PP-ASEL N6TAY
>>See the Geezer Jeep at
>>http://members.***.net/jerrypb/
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

Jerry Bransford

That may be but I would still place the ECU at the dead-end of any list
of likely culprits. :)

reigelser wrote:
> I replaced it allready and all voltages are fine in all ranges of motion of
> the TPS. I also tried to disable other parts of the electric system to see
> if there is an effect on the tps circuit, without success. The error won't
> clear and there is still an effect on the driving behavior.
> "Jerry Bransford" <jerrypb@***.net> wrote in message
> news:kAore.88$X71.85@fed1read07...
>
>>The TJ's ECU is known to be extremely reliable and just about
>>trouble-free. Have you already replaced the TPS and cleaned/reseated the
>>electrical connection that connects the ECU to the TPS? Bad TPSs are
>>easily replaced and far cheaper than replacing the ECU.
>>
>>Jerry
>>
>>reigelser wrote:
>>
>>>I need the ECU eventually because of a persistent TPS error. My mechanic
>>>troubleshooted it and thinks its probably the ECU. But he thinks there
>>>has to be some reprogramming to be done, because I tried one from the
>>>junk yard before he looked into it and nothing changed (same TPS error,
>>>same mileage). It's a 97 inline 6 Cherokee. It works, but it doesn't
>>>start at first try and it is not very smooth if you want to accelerate
>>>from 65 to 75 without a kickdown.
>>>
>>>"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
>>>news:JQXqe.18$kX4.14@newssvr30.news.prodigy.com ...
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:42ABA761.F70549FF@cac.net...
>>>
>>>
>>>>depends on the year starting in 04 all pcm,s are shipped with out
>>>>software and
>>>>it has to progammed by vin
>>>>now more salvage yard pcm swapping
>>>
>>>^^^^^^^
>>>
>>>One letter... how it changes things.
>>>Tim probably meant 'no'...
>>>__
>>>Steve
>>>.
>>>
>>>
>>>
>>>
>>>
>>>
>>>>reigelser wrote:
>>>>
>>>>
>>>>
>>>>>Hi,
>>>>>does anybody know, if there is some programming or calibration to be
>>>>>done if
>>>>>the engine control unit is replaced? Or do I just plug it in and thats
>>>>>it?
>>>>>Thanks for the advice.
>>>>>
>>>>>Jo
>>>>
>>>
>>--
>>Jerry Bransford
>>PP-ASEL N6TAY
>>See the Geezer Jeep at
>>http://members.***.net/jerrypb/
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

Jerry Bransford

That may be but I would still place the ECU at the dead-end of any list
of likely culprits. :)

reigelser wrote:
> I replaced it allready and all voltages are fine in all ranges of motion of
> the TPS. I also tried to disable other parts of the electric system to see
> if there is an effect on the tps circuit, without success. The error won't
> clear and there is still an effect on the driving behavior.
> "Jerry Bransford" <jerrypb@***.net> wrote in message
> news:kAore.88$X71.85@fed1read07...
>
>>The TJ's ECU is known to be extremely reliable and just about
>>trouble-free. Have you already replaced the TPS and cleaned/reseated the
>>electrical connection that connects the ECU to the TPS? Bad TPSs are
>>easily replaced and far cheaper than replacing the ECU.
>>
>>Jerry
>>
>>reigelser wrote:
>>
>>>I need the ECU eventually because of a persistent TPS error. My mechanic
>>>troubleshooted it and thinks its probably the ECU. But he thinks there
>>>has to be some reprogramming to be done, because I tried one from the
>>>junk yard before he looked into it and nothing changed (same TPS error,
>>>same mileage). It's a 97 inline 6 Cherokee. It works, but it doesn't
>>>start at first try and it is not very smooth if you want to accelerate
>>>from 65 to 75 without a kickdown.
>>>
>>>"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
>>>news:JQXqe.18$kX4.14@newssvr30.news.prodigy.com ...
>>>
>>>"tim bur" <dbrider@cac.net> wrote in message
>>>news:42ABA761.F70549FF@cac.net...
>>>
>>>
>>>>depends on the year starting in 04 all pcm,s are shipped with out
>>>>software and
>>>>it has to progammed by vin
>>>>now more salvage yard pcm swapping
>>>
>>>^^^^^^^
>>>
>>>One letter... how it changes things.
>>>Tim probably meant 'no'...
>>>__
>>>Steve
>>>.
>>>
>>>
>>>
>>>
>>>
>>>
>>>>reigelser wrote:
>>>>
>>>>
>>>>
>>>>>Hi,
>>>>>does anybody know, if there is some programming or calibration to be
>>>>>done if
>>>>>the engine control unit is replaced? Or do I just plug it in and thats
>>>>>it?
>>>>>Thanks for the advice.
>>>>>
>>>>>Jo
>>>>
>>>
>>--
>>Jerry Bransford
>>PP-ASEL N6TAY
>>See the Geezer Jeep at
>>http://members.***.net/jerrypb/
>
>
>

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.***.net/jerrypb/

reigelser

To start the car I have to crank it once for a short time. Even If I crank
longer it won't start. Then I turn the ignition off completely and start
again and runs immediately. There was no service done prior to the Check
engine light coming on. The wiper voltage seems very smooth and stable. I
haven't measured the supply voltage while having the engine running yet.
Everything else seems to run good: idle speed, kick down response. So would
you recommend an engine cleaning first (engine compartment wasn't cleaned in
a loooong time) and then a rework of the connectors?
Thanks for all of your advice.

"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
news:rzsre.663$kX4.417@newssvr30.news.prodigy.com. ..

"reigelser" <reigelser@sbcglobal.net> wrote in message
news:Dipre.429$on5.195@newssvr19.news.prodigy.com. ..
> It is an automatic transmission. What is the wiper return voltage? The
> other
> voltage I can measure on the TPS besides the ~200mV to ~4V?
> I check the message with an OBD Reader. P0123 I think is the number or
> P0124, don't remember right now. Are you referring to the Check Engine
> Light
> flashing when you mension a 24 and a 15?

Yes... too cheap to get the OBD. '124' would correspond to
the '24'... TPS.

Start thinking about things like the ground wire
between the engine and the firewall.. this is a
known problem point. Doug has the right
idea... make sure all connections are clean
and tight.

Problem starting... to start an EFI vehicle, you
should keep your foot *off* the gas until the
vehicle has started... no need to touch the
gas until you take off. You're doing this,
right?

Has other maintenance been done recently?
Does the engine run smooth once it starts?
Describe what you have to do to get it
to start (i.e. grind long, grind twice, feather
throttle, etc.).

The TPS is basically a potentiometer, with three
wires going to it... supply, wiper, and ground. The supply
is a regulated voltage, sent by the computer and used
by the computer as a reference. If this is moving around,
the computer may have unfixable problems (blown regulator
pass transistor, etc.) or another sensor or connection may be
screwing up your TPS reading. The wiper voltage is the one that
changes as the throttle plate opens and closes... it should
track the position of the gas pedal steadily. The wiper
carries your 200mV to 4V.
__
Steve
..

reigelser

To start the car I have to crank it once for a short time. Even If I crank
longer it won't start. Then I turn the ignition off completely and start
again and runs immediately. There was no service done prior to the Check
engine light coming on. The wiper voltage seems very smooth and stable. I
haven't measured the supply voltage while having the engine running yet.
Everything else seems to run good: idle speed, kick down response. So would
you recommend an engine cleaning first (engine compartment wasn't cleaned in
a loooong time) and then a rework of the connectors?
Thanks for all of your advice.

"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
news:rzsre.663$kX4.417@newssvr30.news.prodigy.com. ..

"reigelser" <reigelser@sbcglobal.net> wrote in message
news:Dipre.429$on5.195@newssvr19.news.prodigy.com. ..
> It is an automatic transmission. What is the wiper return voltage? The
> other
> voltage I can measure on the TPS besides the ~200mV to ~4V?
> I check the message with an OBD Reader. P0123 I think is the number or
> P0124, don't remember right now. Are you referring to the Check Engine
> Light
> flashing when you mension a 24 and a 15?

Yes... too cheap to get the OBD. '124' would correspond to
the '24'... TPS.

Start thinking about things like the ground wire
between the engine and the firewall.. this is a
known problem point. Doug has the right
idea... make sure all connections are clean
and tight.

Problem starting... to start an EFI vehicle, you
should keep your foot *off* the gas until the
vehicle has started... no need to touch the
gas until you take off. You're doing this,
right?

Has other maintenance been done recently?
Does the engine run smooth once it starts?
Describe what you have to do to get it
to start (i.e. grind long, grind twice, feather
throttle, etc.).

The TPS is basically a potentiometer, with three
wires going to it... supply, wiper, and ground. The supply
is a regulated voltage, sent by the computer and used
by the computer as a reference. If this is moving around,
the computer may have unfixable problems (blown regulator
pass transistor, etc.) or another sensor or connection may be
screwing up your TPS reading. The wiper voltage is the one that
changes as the throttle plate opens and closes... it should
track the position of the gas pedal steadily. The wiper
carries your 200mV to 4V.
__
Steve
..

reigelser

To start the car I have to crank it once for a short time. Even If I crank
longer it won't start. Then I turn the ignition off completely and start
again and runs immediately. There was no service done prior to the Check
engine light coming on. The wiper voltage seems very smooth and stable. I
haven't measured the supply voltage while having the engine running yet.
Everything else seems to run good: idle speed, kick down response. So would
you recommend an engine cleaning first (engine compartment wasn't cleaned in
a loooong time) and then a rework of the connectors?
Thanks for all of your advice.

"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
news:rzsre.663$kX4.417@newssvr30.news.prodigy.com. ..

"reigelser" <reigelser@sbcglobal.net> wrote in message
news:Dipre.429$on5.195@newssvr19.news.prodigy.com. ..
> It is an automatic transmission. What is the wiper return voltage? The
> other
> voltage I can measure on the TPS besides the ~200mV to ~4V?
> I check the message with an OBD Reader. P0123 I think is the number or
> P0124, don't remember right now. Are you referring to the Check Engine
> Light
> flashing when you mension a 24 and a 15?

Yes... too cheap to get the OBD. '124' would correspond to
the '24'... TPS.

Start thinking about things like the ground wire
between the engine and the firewall.. this is a
known problem point. Doug has the right
idea... make sure all connections are clean
and tight.

Problem starting... to start an EFI vehicle, you
should keep your foot *off* the gas until the
vehicle has started... no need to touch the
gas until you take off. You're doing this,
right?

Has other maintenance been done recently?
Does the engine run smooth once it starts?
Describe what you have to do to get it
to start (i.e. grind long, grind twice, feather
throttle, etc.).

The TPS is basically a potentiometer, with three
wires going to it... supply, wiper, and ground. The supply
is a regulated voltage, sent by the computer and used
by the computer as a reference. If this is moving around,
the computer may have unfixable problems (blown regulator
pass transistor, etc.) or another sensor or connection may be
screwing up your TPS reading. The wiper voltage is the one that
changes as the throttle plate opens and closes... it should
track the position of the gas pedal steadily. The wiper
carries your 200mV to 4V.
__
Steve
..

reigelser

To start the car I have to crank it once for a short time. Even If I crank
longer it won't start. Then I turn the ignition off completely and start
again and runs immediately. There was no service done prior to the Check
engine light coming on. The wiper voltage seems very smooth and stable. I
haven't measured the supply voltage while having the engine running yet.
Everything else seems to run good: idle speed, kick down response. So would
you recommend an engine cleaning first (engine compartment wasn't cleaned in
a loooong time) and then a rework of the connectors?
Thanks for all of your advice.

"Stephen Cowell" <scowell@sbcglobal.net> wrote in message
news:rzsre.663$kX4.417@newssvr30.news.prodigy.com. ..

"reigelser" <reigelser@sbcglobal.net> wrote in message
news:Dipre.429$on5.195@newssvr19.news.prodigy.com. ..
> It is an automatic transmission. What is the wiper return voltage? The
> other
> voltage I can measure on the TPS besides the ~200mV to ~4V?
> I check the message with an OBD Reader. P0123 I think is the number or
> P0124, don't remember right now. Are you referring to the Check Engine
> Light
> flashing when you mension a 24 and a 15?

Yes... too cheap to get the OBD. '124' would correspond to
the '24'... TPS.

Start thinking about things like the ground wire
between the engine and the firewall.. this is a
known problem point. Doug has the right
idea... make sure all connections are clean
and tight.

Problem starting... to start an EFI vehicle, you
should keep your foot *off* the gas until the
vehicle has started... no need to touch the
gas until you take off. You're doing this,
right?

Has other maintenance been done recently?
Does the engine run smooth once it starts?
Describe what you have to do to get it
to start (i.e. grind long, grind twice, feather
throttle, etc.).

The TPS is basically a potentiometer, with three
wires going to it... supply, wiper, and ground. The supply
is a regulated voltage, sent by the computer and used
by the computer as a reference. If this is moving around,
the computer may have unfixable problems (blown regulator
pass transistor, etc.) or another sensor or connection may be
screwing up your TPS reading. The wiper voltage is the one that
changes as the throttle plate opens and closes... it should
track the position of the gas pedal steadily. The wiper
carries your 200mV to 4V.
__
Steve
..

DougW

reigelser did pass the time by typing:
> To start the car I have to crank it once for a short time. Even If I crank
> longer it won't start. Then I turn the ignition off completely and start
> again and runs immediately. There was no service done prior to the Check
> engine light coming on. The wiper voltage seems very smooth and stable. I
> haven't measured the supply voltage while having the engine running yet.
> Everything else seems to run good: idle speed, kick down response. So would
> you recommend an engine cleaning first (engine compartment wasn't cleaned in
> a loooong time) and then a rework of the connectors?
> Thanks for all of your advice.

What your describing may be a fuel delivery problem caused by either
the pressure regulator or check valve failing. Try this;

Turn the key on, but don't crank.
Turn the key off, wait a sec
Turn the key on, wait for the fuel pump to stop buzzing
Then try starting the engine.

If the engine fires up your problem is fuel pressure leaking
down. Diagnosing that further is slightly complicated but a cheap
fuel pressure gauge screwed into the fuel rail will indicate a leak
if it drops more than 5psi in an hour. The rail should hold pressure
for more than a day.

--
DougW