need help!!!!
 

hello everyone im new to this site, i have a 1989 cherokee i6 and it never really given me problems until recently now heres the problem when i start the jeep early in the morning and start driving it it starts to stumble and hesitate after a few minutes of driving it goes away but if i get on the freeway itll start doing the same thing but only between 50 and 65 mph. Im stomped on this problem and any advise would be appreciated.

Is the CEL coming up? Any codes?

is it possible to retrieve codes on a 89?

There is no CEL or codes on Renix(87-90) engines...

The Renix motor is a miracle of dumb. Start with the simplest things first... Check all the vaccuum lines for cracks or if they are missing. Check to see if all the electrical connections to see if they are loose or off.

Now is there any reason that water or moisture got into any connections? If there is take them apart and spray them down with something to remove the moisture. CRC makes a VERY good spray for this, WD-40 will work in a pinch.

After that.. the two most likely culprits are the IAC or the TPS. Both of these sensors are located on the throttle body. The IAC is on the back of the throttle body and round. When you pull it out it has a small pintle on the end that is supposed to go in and out when it operates. If it is covered in carbon and soot, take some carb cleaner and clean it really well...

The TPS test procedure requires a multi-meter. Preferably a analog one, but a digital will work in a pinch. There is a really excellent web page containing very detailed descriptions and write-ups on the care and feeding of Renix sensors. Its been posted here a couple of times in other threads. I don't have the page handly to give it to you now.

This is the site that whowey is refering to. You will have to scroll down to the tps. You should bookmark this page as it will come in handy is you own a Renix Jeep.
Kyle Renix Jeeps have no CEL so that would be good for 91 on Jeeps.
Whowey I always use a digital multimeter because they are easier to read and give more precise readings.
http://www.lunghd.com/Tech_Articles/...iagnostics.htm

Thanks...My computer is still conked out.

I use both types of multi-meter. There is one particular test that the analog meter makes easier as you need a sweep reading for it. Which one it is...I dont't remember right now. I haven't had any problems I couldn't trace down to other causes in a LONG time.

so it should definitely be one of these sensors? and all this started when my uncle who is a mechanic replaced the crank sensor im sure that has something with it. thank you guys for your replies

Make sure that CPS is securely plugged in. It should not be your problem as the car will not run if it is unplugged but the recent activity to that plug could be a problem in the future.

:) My bad, it was late and I forgot to check the year:brickwall:

This may sound crazy but I had the same issue after replacing the CPS. the wires run up hook into a clip on the firewall , well being the "mechanic" I am I just ran them and started it up, not putting the wires back into the clip.... Problem there is they run close to exhaust manifold , the insulation melted then they started hitting the manifold and grounding out causing the same issue you have. I would check the wires from the CPS up to the connection. As for the speed variation I just attributed it to wind under the hood? But after taping the wires and putting them back into the clip all was well and still is. If that is not the issue check your O2 sensor had a Ford that acted like that when the o2 went out. Good luck !!

xj4life I assumed that he would not leave the wires laying on the exhaust manifold like you evedentally did. His uncle is a "mechanic" so he would know better than to put the wires in a harmful situation for their well being. He would know that those wires mean run or no run for the Jeep.

We all make mistakes (as I did) and when you look at it it appears as if they would not hit the manifold even when not clipped in.I ment no offence to you or him just trying to help with some first hand experiance.

No, I thought it was a good point that I failed to mention. We all learn from our errors. As that was a learning experience for you, I have made too many to count and want others to benefit from my errors. Thanks xj4.

ill try to change the tps sensor tomorrow hopefully that solves the problem if not i guess ill have no option but to take it to a shop. thank you guys for your help

Damn i must have missed this thread. I am another RENIX owner. You got yourself a keeper. TPS is where i would start, did this problem start before or after your uncle got a hold of it lol.