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HALP 111!!!!11!!!!

M

Marc w

NAXJA Forum User
Location
kwakland
220k mile 1996 OBD2 4.0 cherokee, 5 speed. all new sensors (3 months ago) including, TPS, O2's, IAC, and the others in the throttle body, new cap/rotor/plugs, new air filter, etc. tons of new crap that has been working great for the last few months. today i fired her up after i got out of work, and it wouldnt idle. i had to give it gas to get it to run. WTF. did it for about 15 minutes, died a few times. no codes, no check engine light, nothing......... help me guys. im lost here.
 
I know u said u replaced all sensors... but did you get the Crankshaft position sensor (CPS)? That was my cause and there wasnt a check engine light, also check fuel pressure... could be the fuel pump and or clogged fuel filter......
 
Did you reset the ECU after all those changes?
 
Reset the ECU, and check your battery cable connections. If you unplug the battery, or in most cases leave something on and it dies, the computer has to re-learn all of it's preferences. But after a short trip around town it should settle down.
 
new fuel filter, newer (less than a year) injectors reset the ecu less than two weeks ago, and reset again today after it was freaking out. ran fine after about 15 minutes. have NOT replaced the CPS. meh, easy enough, about 15 minute job, ill replace it. but in 99.9 percent of CPS failures, dont they usually just die and not start? fuel pump is older.
 
I would start with the CPS. Same thing happened with mine and my wife's 2001's.

Then if that doesn't work do the Fuel Pump. They are not that hard. You just have to drop the tank.

Good luck.....
 
cps is easy enough. are they interchangable pretty much? i have a 94 (i think) ax-15 with a new CPS in it, will the OBD1 sensor work in my OBD2 jeep?
 
Couple of thoughts, check that the vac line on the throttle body that feeds the map sensor has not come loose. Test the fuel pressure first, engine off, and engine running. If running fuel pressure is off spec it could be the fuel pressure regulator on the end of the fuel rail (cheaper and easier to replace than fuel pumps). Also check the battery clamps, and the cap and rotor (brand new ones can fail!!!). Did 96 have a fuel pump ballast resistor? Check for loose connections everywhere.
 
Marc w said:
cps is easy enough. are they interchangable pretty much? i have a 94 (i think) ax-15 with a new CPS in it, will the OBD1 sensor work in my OBD2 jeep?
Click to expand...
Check the plug. It might be different. Most of the engine bay connectors changed in 96.

And I second suggestions of ecomike and others to test fuel pressure and run other tests before you throw parts at it.

If your 96 has a steel tank you don't have to drop it to do the fuel pump, though it's more convenient if you do.
 
How old is your battery? With a weak battery, even if the alternator is working ok, you get all kinds of fun. The main symptom is motor is slow cranking , and you get a very low idle or it will not idle at all. When you give it gas, it runs fine. Also, you get no codes.
 
NEW orbital from napa. the bitch will crank for about 10 minutes before it even thinks about slowing down. i will check the fuel pressure tomarrow.
 
Matthew Currie said:
If your 96 has a steel tank you don't have to drop it to do the fuel pump, though it's more convenient if you do.
Click to expand...

steel tank... unless they invented a new plastic tank that holds 3" deep dents :gag:
 
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