emrys_hawke

Got a 95 grand cherokee. engine runs great if i got the gas down but wont idle at all. check engine light is on. took it to a shop and they said after scanning that the only problem was the batter wasn't holding a good enough charge. so bought a battery. problem didn't go away. alternator is good, plugs and wires are good. where should i look next? other symptoms are horrible fuel economy, soot coming out the exhaust, wont downshift correctly and sometimes will stumble when getting up to speed. all the electronics checked out....

DemonGrinder

soot coming out of the exhaust is usually a sign of too rich condition and you are dumping too much fuel which points to an air/fuel mixture problem or a sensor that adjusts these values. I would start with checking cooling temp sensor, there is usually a separate one for the engine computer which adjusts fuel mixture in conjunction with the oxygen sensors.

by the way, what engine do you have, and did they tell you any codes for the CEL ?

emrys_hawke

It has the 5.2. The shop guy told me the code was 41. dont know what that codes for tho and cant seem to find a jeep code guide that i don't have to pay for

Willys55

code 41 is for when the alternator is not charging, and if the battery is run down the alternator is not ramping up the voltage. This can cause rough idle, stalling and internitting surge. Check that the coolant temp sensor is not shorted or open.

emrys_hawke

the coolant temp sensor inside the overflow? And out of curiosity how does the coolant sensor effect the fuel? One more question... went to go check that sensor and the overflow is full of ice... Could that be causing the problem?

zedpapa

when the engine is cold, the computer injects extra fuel much like a choke. when the engine warms up the computer can then run at the correct fuel mixture. if your coolant overflow bottle is full of ice, it could be that your ANTIFREEZE mixture is incorrect. i would suggest draining and filling with the correct mixture. < one thing i would check is the TPS(throttle position sensor). if that is incorrect or missing, it will cause the problems you are describing.

zedpapa

emrys_hawke

k went through and changed the tps. put it on wrong the first time... adjusted it into the right position. Still has many of the same problems. Just for kicks i even replaced the ect (coolant temp sensor), but nothing changed. the only solution at all is i turned the idle screw up to prevent stalling... where should i look next? ive been told that mopar 318s are notorious for having vacuum leaks under the intake manifold... do i need to pull that all apart or is there an easier fix i should start with?

ol"blue

You can check the codes yourself. Here's how. >-> http://jeephorizons.com/phpbb/viewtopic.php?t=2719