Dieseling
 

My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
about one half the time. I think I have the idle and sol-vac solenoid
set OK, but maybe not. I tried disconnecting the vacuum and power to
the solvac solenoid figuring that maybe the carb was being held open a
bit by those, but the problem still occurs. The car does not Ping. Any
thoughts.
Aloha
Joe
Maui HI

Re: Dieseling
 

Many carburated cars will do this if they were shut off cold and
the choke's fast idle cam is still holding the throttle from closing.
Sometimes it's a bad choke pulloff, number 40 at:
http://www.carburetorfactory.com/expvw03.html Or the idles speed
solenoid designed to close the throttle on ignition off, number 9. A
carburetor kit would fix any other problems that may be feeding it gas
while the ignition off.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

Joe and Joann wrote:
>
> My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
> about one half the time. I think I have the idle and sol-vac solenoid
> set OK, but maybe not. I tried disconnecting the vacuum and power to
> the solvac solenoid figuring that maybe the carb was being held open a
> bit by those, but the problem still occurs. The car does not Ping. Any
> thoughts.
> Aloha
> Joe
> Maui HI

Re: Dieseling
 

Many carburated cars will do this if they were shut off cold and
the choke's fast idle cam is still holding the throttle from closing.
Sometimes it's a bad choke pulloff, number 40 at:
http://www.carburetorfactory.com/expvw03.html Or the idles speed
solenoid designed to close the throttle on ignition off, number 9. A
carburetor kit would fix any other problems that may be feeding it gas
while the ignition off.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

Joe and Joann wrote:
>
> My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
> about one half the time. I think I have the idle and sol-vac solenoid
> set OK, but maybe not. I tried disconnecting the vacuum and power to
> the solvac solenoid figuring that maybe the carb was being held open a
> bit by those, but the problem still occurs. The car does not Ping. Any
> thoughts.
> Aloha
> Joe
> Maui HI

Re: Dieseling
 

Many carburated cars will do this if they were shut off cold and
the choke's fast idle cam is still holding the throttle from closing.
Sometimes it's a bad choke pulloff, number 40 at:
http://www.carburetorfactory.com/expvw03.html Or the idles speed
solenoid designed to close the throttle on ignition off, number 9. A
carburetor kit would fix any other problems that may be feeding it gas
while the ignition off.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

Joe and Joann wrote:
>
> My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
> about one half the time. I think I have the idle and sol-vac solenoid
> set OK, but maybe not. I tried disconnecting the vacuum and power to
> the solvac solenoid figuring that maybe the carb was being held open a
> bit by those, but the problem still occurs. The car does not Ping. Any
> thoughts.
> Aloha
> Joe
> Maui HI

Re: Dieseling
 

Aloha Bill
Thanks for the input. It appears that on my carb, based on what I
understand to be the instructions for setting the idle, the solenoid can
only increase the idle in two stages above the curb idle. The first
increase is caused by a the electrical part of the solenoid, the second
by a vacuum signal. It doesn't seem that this sol-vac device can ever
drop the idle below curb idle. Am I thinking about this incorrectly?


Also, The problem occurs when engine is hot so even if the choke pull
off is bad, the choke shoud be well off by then. (Choke does work.)

Will look into the carb kit. Any other ideas?










L.W.(ßill) ------ III wrote:
> Many carburated cars will do this if they were shut off cold and
> the choke's fast idle cam is still holding the throttle from closing.
> Sometimes it's a bad choke pulloff, number 40 at:
> http://www.carburetorfactory.com/expvw03.html Or the idles speed
> solenoid designed to close the throttle on ignition off, number 9. A
> carburetor kit would fix any other problems that may be feeding it gas
> while the ignition off.
> God Bless America, Bill O|||||||O
> mailto:-------------------- http://www.----------.com/
>

Re: Dieseling
 

Aloha Bill
Thanks for the input. It appears that on my carb, based on what I
understand to be the instructions for setting the idle, the solenoid can
only increase the idle in two stages above the curb idle. The first
increase is caused by a the electrical part of the solenoid, the second
by a vacuum signal. It doesn't seem that this sol-vac device can ever
drop the idle below curb idle. Am I thinking about this incorrectly?


Also, The problem occurs when engine is hot so even if the choke pull
off is bad, the choke shoud be well off by then. (Choke does work.)

Will look into the carb kit. Any other ideas?










L.W.(ßill) ------ III wrote:
> Many carburated cars will do this if they were shut off cold and
> the choke's fast idle cam is still holding the throttle from closing.
> Sometimes it's a bad choke pulloff, number 40 at:
> http://www.carburetorfactory.com/expvw03.html Or the idles speed
> solenoid designed to close the throttle on ignition off, number 9. A
> carburetor kit would fix any other problems that may be feeding it gas
> while the ignition off.
> God Bless America, Bill O|||||||O
> mailto:-------------------- http://www.----------.com/
>

Re: Dieseling
 

Aloha Bill
Thanks for the input. It appears that on my carb, based on what I
understand to be the instructions for setting the idle, the solenoid can
only increase the idle in two stages above the curb idle. The first
increase is caused by a the electrical part of the solenoid, the second
by a vacuum signal. It doesn't seem that this sol-vac device can ever
drop the idle below curb idle. Am I thinking about this incorrectly?


Also, The problem occurs when engine is hot so even if the choke pull
off is bad, the choke shoud be well off by then. (Choke does work.)

Will look into the carb kit. Any other ideas?










L.W.(ßill) ------ III wrote:
> Many carburated cars will do this if they were shut off cold and
> the choke's fast idle cam is still holding the throttle from closing.
> Sometimes it's a bad choke pulloff, number 40 at:
> http://www.carburetorfactory.com/expvw03.html Or the idles speed
> solenoid designed to close the throttle on ignition off, number 9. A
> carburetor kit would fix any other problems that may be feeding it gas
> while the ignition off.
> God Bless America, Bill O|||||||O
> mailto:-------------------- http://www.----------.com/
>

Re: Dieseling
 

Do you have AC or an automatic? If so you need the solenoid, otherwise
it has no function except to get in the way...

The idle should be 500 rpm with the solenoid unplugged and then you set
the solenoid for the 750 idle. If you have an automatic, it should be
in drive while adjusting.

Then you could just be carboned up from too many short drives with low
octane.... Just FYI, the owners manual for the 258 with the BBD states
high octane might be needed to stop the ping or load rattle if the
engine is run hard, hot and loaded. The computer uses a knock sensor
for low octane gas.

You can decarbon the engine. I was taught to use a pint of ATF to do
this, others swear a pint of water works also. I know first hand that
the ATF treatment will make the inside of the combustion chamber look
like new.

I get the engine warmed up and remove the air filter. While keeping the
rpm up with my hand on the throttle linkage, I slowly pour the ATF down
the carb keeping it revving enough not to stall. Once the ATF is all
in, I shut off the engine for a few minutes, then start it up and go.

Warning! This will make a thick white cloud of smoke. Neighbors are
likely to call the fire dept. if they don't know what's up.

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)

Joe and Joann wrote:
>
> My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
> about one half the time. I think I have the idle and sol-vac solenoid
> set OK, but maybe not. I tried disconnecting the vacuum and power to
> the solvac solenoid figuring that maybe the carb was being held open a
> bit by those, but the problem still occurs. The car does not Ping. Any
> thoughts.
> Aloha
> Joe
> Maui HI

Re: Dieseling
 

Do you have AC or an automatic? If so you need the solenoid, otherwise
it has no function except to get in the way...

The idle should be 500 rpm with the solenoid unplugged and then you set
the solenoid for the 750 idle. If you have an automatic, it should be
in drive while adjusting.

Then you could just be carboned up from too many short drives with low
octane.... Just FYI, the owners manual for the 258 with the BBD states
high octane might be needed to stop the ping or load rattle if the
engine is run hard, hot and loaded. The computer uses a knock sensor
for low octane gas.

You can decarbon the engine. I was taught to use a pint of ATF to do
this, others swear a pint of water works also. I know first hand that
the ATF treatment will make the inside of the combustion chamber look
like new.

I get the engine warmed up and remove the air filter. While keeping the
rpm up with my hand on the throttle linkage, I slowly pour the ATF down
the carb keeping it revving enough not to stall. Once the ATF is all
in, I shut off the engine for a few minutes, then start it up and go.

Warning! This will make a thick white cloud of smoke. Neighbors are
likely to call the fire dept. if they don't know what's up.

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)

Joe and Joann wrote:
>
> My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
> about one half the time. I think I have the idle and sol-vac solenoid
> set OK, but maybe not. I tried disconnecting the vacuum and power to
> the solvac solenoid figuring that maybe the carb was being held open a
> bit by those, but the problem still occurs. The car does not Ping. Any
> thoughts.
> Aloha
> Joe
> Maui HI

Re: Dieseling
 

Do you have AC or an automatic? If so you need the solenoid, otherwise
it has no function except to get in the way...

The idle should be 500 rpm with the solenoid unplugged and then you set
the solenoid for the 750 idle. If you have an automatic, it should be
in drive while adjusting.

Then you could just be carboned up from too many short drives with low
octane.... Just FYI, the owners manual for the 258 with the BBD states
high octane might be needed to stop the ping or load rattle if the
engine is run hard, hot and loaded. The computer uses a knock sensor
for low octane gas.

You can decarbon the engine. I was taught to use a pint of ATF to do
this, others swear a pint of water works also. I know first hand that
the ATF treatment will make the inside of the combustion chamber look
like new.

I get the engine warmed up and remove the air filter. While keeping the
rpm up with my hand on the throttle linkage, I slowly pour the ATF down
the carb keeping it revving enough not to stall. Once the ATF is all
in, I shut off the engine for a few minutes, then start it up and go.

Warning! This will make a thick white cloud of smoke. Neighbors are
likely to call the fire dept. if they don't know what's up.

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)

Joe and Joann wrote:
>
> My 1990 Jeep YJ, 258, has started dieseling after shut off. Does it
> about one half the time. I think I have the idle and sol-vac solenoid
> set OK, but maybe not. I tried disconnecting the vacuum and power to
> the solvac solenoid figuring that maybe the carb was being held open a
> bit by those, but the problem still occurs. The car does not Ping. Any
> thoughts.
> Aloha
> Joe
> Maui HI