My jeep has had a funny idle when warming up on a wet day. It's
always been like this. I bought it new and the mechanics said that it
was just cold blooded. Now it's 16 years old. It runs so bad after
a wet day that I had to do something. I unplugged the hose to the
EGR valve and that seem to do it, but that isn't a real fix. Where
are some good places to look for this problem. (I don't mean the internet)
I mean the parts on the jeep. It is time to replace the O2 sensor?
I've watched the electronically controlled mixture pin move in and out
as it should, and there's no extra gas dripping down the inside
of the carburetor as well.

 

Newsmanager@Gsd-Co.Com wrote:

> My jeep has had a funny idle when warming up on a wet day. It's
> always been like this. I bought it new and the mechanics said that it
> was just cold blooded. Now it's 16 years old. It runs so bad after
> a wet day that I had to do something. I unplugged the hose to the
> EGR valve and that seem to do it, but that isn't a real fix. Where
> are some good places to look for this problem. (I don't mean the internet)
> I mean the parts on the jeep. It is time to replace the O2 sensor?
> I've watched the electronically controlled mixture pin move in and out
> as it should, and there's no extra gas dripping down the inside
> of the carburetor as well.

Replacing the O2 sensor is a good idea, especially with a Jeep that old.
However, usually, a poor running vehicle on a wet day is ignition related
as electicity doesn't efficiently conduct if moisture is present. You might
try swapping out the coil for something stronger or going with an MSD type
mult-spark discharge. A good tune-up with quality parts like Standard or
Mopar is a good idea too. It could even be that the distributor cap doesn't
seal well to the distributor because of a flaw in the contact surface on
the distributor and it lets moisture in. It could be many things, but I'd
look at the ignition system for what ails this type of condition.

 

If unplugging the EGR has an effect on the idle, then the EGR is a bad
one.

Sounds like it was a defective one from day one too.

Other than that, I always suspect carbon tracks inside the distributor
cap first for wet running problems and leaky wires second.

You can test the wires easily, at night get it running and use a spray
bottle to mist the wires with water. If you get a light show, the wires
are worn out and leaky.

A good strong light or direct sun is handy for looking for carbon tracks
inside the cap, they look like faint spider web marks and can be white
or black.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Newsmanager@Gsd-Co.Com wrote:
>
> My jeep has had a funny idle when warming up on a wet day. It's
> always been like this. I bought it new and the mechanics said that it
> was just cold blooded. Now it's 16 years old. It runs so bad after
> a wet day that I had to do something. I unplugged the hose to the
> EGR valve and that seem to do it, but that isn't a real fix. Where
> are some good places to look for this problem. (I don't mean the internet)
> I mean the parts on the jeep. It is time to replace the O2 sensor?
> I've watched the electronically controlled mixture pin move in and out
> as it should, and there's no extra gas dripping down the inside
> of the carburetor as well.

 

On Sun, 03 Aug 2003 12:06:32 -0400 in rec.autos.makers.jeep+******,
Mike Romain <romainm@sympatico.ca> wrote:

>If unplugging the EGR has an effect on the idle, then the EGR is a bad
>one.
>
>Sounds like it was a defective one from day one too.

Check The CTO (Coolant Temp Override) valve. It is the job of the
CTO valve to block vacuum from reaching the EGR until the engine
starts to warm up. If a vacuum gauge shows vacuum reaching the EGR
valve when the engine is cold, the CTO is not doing its job. The
engine is not supposed to handle the EGR functioning while the
engine is cold. CTO = about $25.

 

David Harmon wrote:
>
> On Sun, 03 Aug 2003 12:06:32 -0400 in rec.autos.makers.jeep+******,
> Mike Romain <romainm@sympatico.ca> wrote:
>
> >If unplugging the EGR has an effect on the idle, then the EGR is a bad
> >one.
> >
> >Sounds like it was a defective one from day one too.
>
> Check The CTO (Coolant Temp Override) valve. It is the job of the
> CTO valve to block vacuum from reaching the EGR until the engine
> starts to warm up. If a vacuum gauge shows vacuum reaching the EGR
> valve when the engine is cold, the CTO is not doing its job. The
> engine is not supposed to handle the EGR functioning while the
> engine is cold. CTO = about $25.

Good point, but the EGR line also has to go through the thermostat in
the air filter and vacuum should not be present in any of the EGR lines
until the engine is at speed.

It uses a 'ported' vacuum signal.

Now his plumbing could just be plain wrong with a manifold vacuum tag on
the wrong place on his CTO valve....

Mike