1994GrandChLtd Idle/Stall Problems

[AaronB]

A friend just gave me a 94' Grand Cherokee Ltd w/ a the high output 5.2LV8. It stalls when idling, and occasionally while driving and slowing down. I just changed the plugs, and the plugs I removed wreaked of gasoline. It seems to have fine spark. A mechanic suggested the Idle Air Control motor was bad. Any ideas?
Thanks, AB

 

[sparkyshotrods25]

I WOULD SUJJEST CHECKING THE SPARK PLUG GAP,IT SHOULD BE AT 35,NEXT MAKE SURE YOUR WIRES ARE GOOD.tAKE THE AIR CLEANER ASSEMBLY OFF THE THROTLE BODY AND OPEN THE CHOKE.uSE SOMETHING TO HOLD IT OPEN AND CLEAN IT WITH CARB CLEANER AND A OLD TOOTHBRUSH.MAKE SURE YOU WIPE IT OUT AS BEST YOU CAN AFTER YOU ARE DONE.NEXTCHECK YOU TIMING.IT SHOULD BE AT THE 0* MARK.IT IF IS BOUNCING MORE THAN LIKELY IT IS TRYING TO COMPENSATE FOR THE CHAIN BEING OFF.MOST OF THE TIME IT IS GOING TO BE THE TIMING BEFORE ONE OF THE SENSORS.i WOULD DO A COMPUTER DIAGNOSTIC AND PULL THE CODES IF IT WAS THE IDLE AIR CONTROL MOTOR,IT WOULD COME UP.AN O2 SENSOR COULD BE A CULPRATE AND A CODE WILL ALSO COME UP FOR THAT.MIGHT GET A CODE23 IF THE AIR SENSOR IS BAD.

 

[XJNick]

Hi,

I'd suspect a bad Crankshaft Position Sensor (CPS). When these malfunction they can cause the vehicle to randomly die.

-Nick :!:

 

[AaronB]

Thanks
I just put in new plugs w/a gap of 35. As far as the timing, apparently the only way to adjust the timing is by replacing the PCM(Powertrain Control Module), about $260. I haven't been able to bring up the trouble codes. The manual talks about clicking the ignition on/off 3 times and codes will come up. Nothing has. Either I am doing it wrong, or there are no trouble codes at this time. Any advice on getting the codes? Thanks

 

[Bounty__Hunter]

The procedure for getting the codes on your jeep should be to turn the ignition from off to run 3 times, leaving it on run at the end. The check engine light will flash if it's thrown any codes.

You can remove the IAC sensor and housing and clean them up with some carb cleaner and a toothbrush. I'd try this before replacing it.

 

[AaronB]

Thanks again for helping me track this down. I just took it for a spin, it hesitated quite a bit on acceleration, and coughed out some whitish/blue exhaust. I got two codes, 12 and 55, basically, codes cleared.

Does the fact that no trouble codes are coming up mean that I can eliminate sensors as the problem? And could it be a fuel pressure regulator?

Thanks again!

 

[Bounty__Hunter]

With no codes being thrown it sounds like bad gas, or a clogged fuel filter.

Get yourself some 'SeaFoam', it's available at most autoparts stores. Follow it's directions for adding it to the fuel tank, and use what's left in the intake and crankcase according to directions. Great stuff.

 

[AaronB]

I put some Sea Foam in, no big change yet, but maybe it takes a while to work through the system.

I found out that this vehicle recently had a new camshaft sensor put in because it wouldn't start. The fuel pressure read fine, and so the new sensor did the trick to start it, but the stalling and rough running remains. Would the fuel pressure read normal if the fuel filter was clogged?

I did a spark test, there is definitely spark. But could this stalling/hesiation etc be in the distributor area, rotor or ignition coil? Thanks again for your help.
Aaron B