My '89 XJ w/ 4.0L is acting up and I need to fix it by Friday. It will run ok at idle (even though the throttle acts like it carburated instead of fuel injected), and when I put it in drive it will drive OK at best. Once it gets up to normal operating temp and I drive it for a minute or so, the engine won't rev past like 2000 rpm's and it spits and sputters like its flooding. I've already ruled out intake issues, fuel filter, exhaust is brand new (including cat), TP sensor is brand new (but I havent had it "adjusted"), I put a whole new vacuum line kit for the emission system on it, new EGR valve, I cleaned the injectors and replaced the seals yesterday, brand new distributor w/ wires, and still haven't got it to drive like normal. Today I'm going to test the MAP sensor and pull the fuel pump out and look at it. I bought this Jeep 2 weeks ago and let's just say the guy I bought from was VERY careless with it. Need help ASAP. thanks.

 

o2 sensor.

 

Oh, no it's not the O2 sensor either. I forgot to list that I changed that out 2 days ago and it didn't fix it either.

 

This is where i would start... makes too much sense not to be obvious.

 

Where can I have it adjusted at?

 

Nevermind. I just found an article that explains how to adjust the TPS with a voltmeter.

 

https://www.cherokeeforum.com/f2/jus...-issues-72894/

Or take to a mechanic

 

Thanks overland.

 

well tested to MAP sensor and that was good. Now im having starting issues too and my friend (pretty good mechanic) said that I should check out the fuel pump and fuel lines. My first post stated that I have a brand new exhaust incl the cat, but the more I read about my problems and symptoms it points to either a fuel problem or a clogged cat. I have tested or replaced all sensors except for the CTS, MAT sensor, and CPS. Im running out of ideas...

 

does 89s have an o2 after the manifold? two o2s? if it does id make sure i change both, mine was doing the smae thing you described and it was the 02 right after the manifold.

 

I dont think it has two O2 sensors. The more I read about problems with heat soaked CPS's, the more I think I have a faulty CPS. I guess thats where Ill start tomorrow.

 

try removing it and cleaning also check for bare wires touching on it

 

The first thing I'd check is to see if any codes are stored in the PCM.

Turn the ignition key On-Off-On-Off-On, and watch the flashes of the Check Engine light. The 2 digit code will point you right to the sensor or sensor circuit that is giving you trouble.

A code "55" is End of Test; if no trouble codes are stored, that's information in itself. You could then look elsewhere than the computer and its sensors - things like fuel pressure, ignition system condition, and so forth.

Let us know what you find!
Dan

 

The one thing everyone has missed here is the catalytic converter. Over time the insides break down and it becomes clogged and won't let the engine "breathe" properly. The symptoms you have described are typical cat failure symptoms. Have it checked asap as it can cause gaskets to blow out due to rising exhaust pressure.

 

Thanks Dan. Yeah I thought about checking the PCM for codes on the second day I bought it, until I realized that the guy I bought it from is an idiot and didnt take care of it at all. most of the lights and interior stuff is either disconnected or just plain broken. It has a steering column from a chevy in it... I didnt even realize it until my friend pointed it out to me. This thing needs a lot of work and I have my hands full on rebuilding it. Right now Im just trying to make it road worthy, so I can get home on friday. If not, Im going to have to swallow my pride and rent a dolly so my buddy can tow me home in his 2008 Dodge Ram 2500 cummins... So im trying everything in my bag of tricks to get it running the RIGHT way, not just half ***** running like it was when I bought it.

Thanks for all the help everyone. Ill keep you guys up to date on how its going tomorrow after I tinker with the CPS and possibly the fuel pump.

By the way, thanks for reminding me about that TP sensor adjustment Overland. Even though it isnt running well now, that TPS was way off of .830...

Wish me luck tomorrow!