finneys98xj

I am in need of help please, My heep start bucking on me the other day. It back fired once or twice and wouldnt hardly pull a hill. I hae replaced the cps, plugs, cap and button aint that old. I also noticed she ran alittle warmer on the way home after she did that.

claygrassmann

tps? iac? fuel pump? injectors?

finneys98xj

I was thinking maybe tps but cant remember the way it acts when it fails

BuckB91XJ

Finney, do the fuel pump pressure test. Sounds like a bad fuel pump to me. My son's XJ did the same thing when his fuel pump died. Started bucking like a bronco while pulling a hill then died on him.

finneys98xj

While I hit the button on the fuel rail while it was running and the jeep would shoot gas about 10-15 foot

sean882

I had a car that did that once when the O2 sensor was getting really bad. Replaced it, and I was all set.

EvilBlackXJ

Catalytic converter clogged?

finneys98xj

Aint got one at the moment!

4.3L XJ

Finney.

Most ECMs are programed to have that back pressure in the system. That might be part of your problem.

finneys98xj

It has ran fine for the past month with a gutted cat(Dont want to he it about the cat guys I KNOW) and muffler. So I dont think it is that. What would the timing do if it started to go?

dangerousdavid

have you checked your injectors? they could be clogged. i dont think that the cat would do that becuase i'm running a straight pipe from my downpipe to my muffler (the one that just got ripped off last weekend down in hot springs) and i've never had that problem.

CoastyGuardCutter164

remember guys there was a system we would use when I was in the uscg call the Kiss method,( Keep it simple stupid) go with your plugs wire rotor cap, Make sure when you replaced your cap an rotor that its set right. Also make sure your plugs are set at the proper gap. (most auto centers say their pre grapd only to find out they were off) With your jeep back fireing this could be the reason for being off timeing or possibly jumped the timeing on your jeep. Also make sure when you replace all your plugs an wire to make sure their in the proper fireing order, again this is call theory cuz none of this jeep in our possesion to make the assment in her, i'm sure you will figure it out good luck to you sire,

"Semper Paratus"

JeepCoMJ

with your high mileage, it is possible that the timing chain let loose a bit and jumped a few teeth.


most likely, though you have either a bad fuel pump (your test at the rail doesn't work. it's wrong and shows no proof or disproof that the pump is bad....you must use a fuel pressure test gauge), or a bad 02 sensor.

my buddy's exo'd 95 xj did the exact same thing when he cracked his o2 sensor

finneys98xj

I aint got a fuel pressure tester but maybe able to get one to use. and where are the 02 sensors on a 93?

The cap is on right cause it has been on for 10,000 miles I just replaced the plugs and set the gap myself 300 mile atlest.

4.3L XJ

USCG 1969-75