so my dad has 99 4.0 jeep it does not have the 1331 head that is junk but he overheated it and blew the head gasket. we replaced the gasket and no more overheating but it is still running rough and missing. it threw a cel for high tps input and one for low input. my dad replaced the tps but same thing........what gives? i do not see an obvious issue.
jeep cherokee issues
- Thread starter Dakota1820
- Start date
- Status
when it first starts up it'll be about 1400 rpm as it warms up it'll go to 1600 rpms. and as it warms up my dad turned the lights on to see the dash and it went to 3000 rpms and wouldn't come down. when running at 1500 the tps percent was about 16.9 with .4volts. it all looks fine.
4.0s 99.999% of the time aren't going to blow the head gasket; they crack the head.I'd look at getting a junkyard head on it, otherwise you're going to ruin the engine.
The 0331s are more susceptible to it, but any of the heads on the 4.0 will crack if overheated enough.
The 0331s are more susceptible to it, but any of the heads on the 4.0 will crack if overheated enough.
Sounds like air is getting in there somehow... cracked head, ill-seating intake manifold? Running lean is BAD for gassers. Pull the head and have it magnafluxed to check for cracks.
Some had an adjustment you could make for the TPS. I don't think '99 did, but you might want to look into it. I agree with the suggestion to look for damaged wires to the TPS. Also, since the idle goes high, check for a leaking intake gasket.
there is no adjustment. we didn't see any cracks but he didn't want to have it checked..... i thought doing a compression check would be a good idea and spraying starting fluid around the intake to see if its leaking
Hvac works fine. When it first started it didn't do this it took ten or 15 mins of running then started acting up
Where did you buy the TPS? Cheap parts store TPS can be bad right out of the box. I only buy sensors from Jeep now.
Are you sure this '99 has the 0331 head? Does it have the coil on plug ignition? Usually '99s have a distributor and the better 0630 head casting.
Are you sure this '99 has the 0331 head? Does it have the coil on plug ignition? Usually '99s have a distributor and the better 0630 head casting.
Yea it has the 0630 head. Tps shows good
Can you pull the intake stuff and get at the throttle body, and still have it run? (If it has a MAF, unplug it-- should still idle.)
You should see an idle air bypass, cover this with your thumb. If it drops to low idle, the computer is commanding high idle. If it doesn't change anything, you have a vacuum leak.
You should see an idle air bypass, cover this with your thumb. If it drops to low idle, the computer is commanding high idle. If it doesn't change anything, you have a vacuum leak.
Originally Posted By: AVB
That really is suprising to me that they were still using vacuum in 99. I have seen a Chevy van or two that used vacuum. I don't recall the model years now, but I was kind of shocked when I saw they were still using vacuum.
No big surprise there- the last Cherokee re-design was in 1996, and non-vacuum HVAC blend doors and such were still pretty much only used on automatic climate-control vehicles at that time. No such option on an XJ.
That really is suprising to me that they were still using vacuum in 99. I have seen a Chevy van or two that used vacuum. I don't recall the model years now, but I was kind of shocked when I saw they were still using vacuum.
No big surprise there- the last Cherokee re-design was in 1996, and non-vacuum HVAC blend doors and such were still pretty much only used on automatic climate-control vehicles at that time. No such option on an XJ.
Originally Posted By: AVB
I would not use starting fluid, I would use something with a jet spray like brake cleaner.
NEVER use brake cleaner for that! For one thing, it doesn't burn at all... its non-flammable (at least the "red can" type that works the best for cleaning things, the "non-chlorinated" type may actually burn).
But the really bad thing is that when you put it through a flame, it breaks down chemically into some REALLY nasty compounds that can seriously damage your lungs and eyes in a matter of seconds when they come spewing out the exhaust pipe...
I would not use starting fluid, I would use something with a jet spray like brake cleaner.
NEVER use brake cleaner for that! For one thing, it doesn't burn at all... its non-flammable (at least the "red can" type that works the best for cleaning things, the "non-chlorinated" type may actually burn).
But the really bad thing is that when you put it through a flame, it breaks down chemically into some REALLY nasty compounds that can seriously damage your lungs and eyes in a matter of seconds when they come spewing out the exhaust pipe...
- Status
