problems with a 95 jeep

[rooster4473]

im having running problems w my 95 jeep grand cherokee, it has 5.2 in it, would anyone be able to help me or is it not considered a dodge or chrysler?

[Mopar1973Man]

what kind of problems?

[ISX]

Your in the right section, this is for anything made by chrysler (dodge/jeep/etc.) If you were wrong we would move it to the right section for you :thumbup2:Let us know what you have wrong with it and someone will help.

[flagmanruss]

We're a friendly (and helpful) group here... otherwise, I'd never make it. Tell us about your Jeep or better yet fill in your signature with as much info as you can think of.

[rooster4473]

Cool, the jeep will idle ok and run ok as long as you baby it and dont go over 2k rpm, after that the motor "surges", acting like its running out of gas, itll rev up then drop idle over and over and pop out the exhaust, and it loses power, I changed the fuel filter and im getting about 38lbs of fuel pressure. I also cleaned the IAC, just cuz its there and easy. The ck engine light is not on and if you do the key cycle its bringing up code 12, the guy at the parts store said wires cap and rotor, but theyre less then a year old, not that they couldnt be bad, but I was leaning more towards the egr or tpc? Any suggestions?

[Mopar1973Man]

Question? What is your fuel pressure ar at this 2K RPM's? Is the fuel rail draining off from a weak fuel pump or plugged filter causing the engine to surge because it trying to fuel more and it can't... 12 flash code means the battery was disconnected at one point. Vacuum leak? You'd be surprised what a vacuum leak will do to these newer electronic fuel injection vehicles...

[rooster4473]

it seemed to hold pressure, maybe dropped a lil down to 35 or so when i was powerbraken it, and i just changed the filter, and i didnt c any vacuume lines off.

[Mopar1973Man]

Sorry to say you'll have to see what it like under road load. 35 seems a bit low though...

[rooster4473]

Im not even sure how much fuel pressure it should have, the book says with the regulator vacuum hose on 31-33psi and when the regulator vacuum hose is off 39-41psi, but there is an exception for the '95 cuz the regulator is on the pump in the tank and it doesn't give the specifics for it.

[cummins2k]

The fuel pressures actually sound fine for a Magnum V8. I have a Dakota with a Magnum V6 (basically the same engine as the 5.2 missing two cylinders) and it exhibits a similar problem. I have two separate things happening and just haven't got around to fixing it because it never gets driven. Here is what is going on with mine and the causes, maybe this will help :thumbup2:Around 1800-2000 rpms it will buck / surge and if I shift (manual trans) it will exhibit a minor back fire. There is a hall effect sensor under the distributor rotor that controls the sync of the injectors, this was out of wack on my truck. Ultimately this should be set using a diagnostics scanner while turning the distributor much like setting the ignition timing on an older vehicle. The dealership has the proper scanner for this. It can be "set" by piercing or back probing the wires and using a multimeter however this is inaccurate and can be off a few degrees so there is a lot of trial and error involved. It is recommended to use the scanner and set it while running around 1000 rpm because there is less slack in the timing chain at this speed.Also my timing chain is bad, hence the reason I have never bothered fixing the first problem. It is bad because the chains are actually a bit to big for the Magnum engines as they moved the cam bore down slightly vs the pre-magnum engines and kept the same length chain. Chrysler sells a kit to tension the chain and prevent this. If this is compounding your problem then you would hear it my truck sounds like a diesel at idle but give it a bit of throttle and the sound goes away.

[rooster4473]

That hall sensor sounds like my problem, but my jeep sounds fine at an idle. Would the sensor just mess up all of the sudden? Wouldnt it make a code come up or the check engine light come on? Im still driving the jeep, Im just kinda babying it right now. It is kinda funny tho, mine backfires a good bit, and of course I thought reving the heck out of it would fix it, , and I blew up a brand new muffler!