cherokeeyed

1988' Cherokee, this Jeep since day one has given me nothing but a headache, literally. I'm on the verge of dumping it but would like to get it running right before pushing it off on someone else.


I have established:


C101 Connector is clean
Grounds at dip stick are clean
TPS adjustment using a voltmeter.
Spark
Fuel pressure at rail with a gauge (idling and off)
Map sensor by unplugging the vacuum line next to it while running


If you see this Cruiser which I'm sure you will, when checking TPS in a post on your renix tips it said "If you see more than 1 ohm of resistance, or fluctuation in your ohms reading, some modifications to the sensor ground harness will be necessary. The harness repair must be performed before proceeding. I can provide an instruction sheet for that if needed."


I didn't see where it said which grounds or where they were located or any of that. I'm about 98% positive I had the key off when I checked this portion of the TPS but I could be wrong. My reading was in the neighborhood of 69.xx, any help is much appreciated.


The issue that remains and always has been is Idle and start up.


Start up: With the butterfly inside the throttle body adjusted correctly according to cruisers adjustment instructions, no matter what, I HAVE to give the Jeep gas to get it to fire. It will just crank if I don't give it gas. If I open the butterfly with the adjustment screw to a more than factory spec the Jeep will start without giving it gas.


Idle: Same as start up, with the butterfly adjusted correctly according to Cruiser's instructions the Jeep will not idle, occasionally it will but 98% of the time it either dies or spits, sputters and then usually dies unless I give it gas.


I've about had it with this Jeep. This is my 4th XJ and first Renix, I will not own another Renix I'm almost positive.

EvstaG

I think you might've just gotten a bad one of the batch :P Have you been able to troubleshoot the idle air control valve? This would seem like a likely culprit...

cherokeeyed

I have cleaned the IAC. Is there a way to check it as far as functioning properly? If anything I'll just replace it but I would like to verify its bad before just throwing money at it.

je4reyk

If I read your post correctly you have 69.xx ohms to ground. If I'm reading that right, thats like 100% of the problem

cherokeeyed

I'm re-checking that in about 30 minutes just to make sure I didn't have the key on.

cruiser54

See post 6 in my link, after reading post 5.

je4reyk

Key or no key you are checking grounds to negative battery post . I know it surprised me when I checked mine ,even when I checked negative battery post to chassis . It make a huge difference on a Renix jeep

je4reyk

Ok so I just reread Crusers tips leave the key off like he said that way all tests are done the same way making the results valid. Sorry for the confusion.

cherokeeyed

Thanks for all your help and insight Cruiser, as well as everyone else giving me feedback. I will re-check the grounds tomorrow and continue with post 6 if I have a problem.


If the grounds are in good shape, where do I go from there?

cruiser54

Don't approach it that way. Looking to the next problem, that is. Do the ground check and THEN we'll see where we're at. Sometimes automotive diagnosis is making sure what it ISN"T before we find what it IS. Lots of times we fix it along the way!!

cherokeeyed

With the key off, grounding to the battery and probing b on the flat 3 I'm getting 2.5 Ohms.

cherokeeyed

I re did the grounds. I'm not getting .5 Ohms at grounding to the battery and probing B off the flat 3. I think I might now need to reset the tps considering I set it with the grounds off?

cruiser54

Yep. Good job.

cherokeeyed

I re-did the grounds, mentioned in your post and like previously stated grounding at the battery and probing B, I'm getting .5 Ohms. I then reset the TPS using your instructions and have it spot on.


Now on the initial start up, when cold sometimes I have to give it gas sometimes I don't. Either way when it first fires, for about the first minute of running it runs rough, has a little lope to the idle and then after running for a minute or two the idle will clean up to completely normal... the idle initially is not normal that's for sure.

cruiser54

Every time you screw with the butterfly, which you chould stop doing nw, you need to re-adjust the TPS on the engine side.

Refresh me here. You did the sensor ground test, right?