HolyCow

I had posted a thread earlier about this idle problem, it may have been taken off, not sure. I'll ask again. I know this is a jeep wagoneer and not a cherokee, but they are built similar- I assume. If not sorry. Question? 87 Jeep wagoneer-multi port fuel injection- 4 L- I guess- straight 6- 4 wheel drive. Anyhow, it idles O.K. in park, but when I get it on the road and come to a stop it dies. Under hood a tag on firewall says curb idle is non adjustable. I am going to put new plugs in and check hoses, but I think hoses are O.K. I have checked them out and I don't see any loose hoses or splits or anything like that. Only other thing I can think of is the plugs and wires. Any help appreciated. Thanks!

Abovetimberline

Have you checked your iac,or 02 sensor? somtimes your tps can also change by coming loose or is starting to go bad,I would start by looking at these things.
Also you can adjust your idle by bending the little tab on the throttle body where the throttle rest or the linkage itself,the L shaped linkage that goes from the cable to the throttle bodly. But you should not have to do this,it is something else that is the problem.
Not sure why your previous post was deleted,maybe someone posted something in violation of forum rules that you are not aware of.

HolyCow

iac-02 sensor-tps- I am not familiar with fuel injection, so these terms sre new to me. 02 sensor I assume is the sensor on the muffler or catalic converter-the other terms I am not familliar with. Any info on how to check these. I have a crapy chilton book, that may be of some help. I really do need to get a factory service manual.

fantic238

DON'T DO THAT! it only masks the real problem!
Start with a cleaning of the throttle body, with some carb cleaner, clean all the grime inside around the throttle.
The IAC is the idle stepper motor that regulates idle speed. Unplug the connector when the idle is correct and drive around to see if it stays like that. If it dies it is not the IAC.
Check your fuel pressure when it dies, you should borrow a press gauge and be able to read it while driving, when it dies.
Other than that could be vacuum leak at MAP(manifold absolute pressure) sensor or TPS(throttle position sensor) adjustment.
leave the O2 sensor alone, it is useless on Renix(yours) Jeeps.
The wagoneer and the cherokee are the same thing.

HolyCow

Wow! Sounds like a lot to check. I'll have to get a good service manual, because this is kind of new to me. I am use to working with regular carbs with no fuel injection. I'll have to learn on this one, but a few books should give me a good idea. I also have slow acceleration, less than I use to have. Feels like the transmission is slow at first, gets better as it warms up. I took it to jiffy loobe, before I had this slow acceleration problem, they replaced oil and transmission fluid. I am wondering if they put the wrong fluid in it. I checked transmission and it is full on dip stick. It may be because of the idle problem, not sure if there related.

HolyCow

In reference to my idle problem, I thought I might mention the fact that: I worked on my ignition switch before the idle problem happened. Is there something under the dash board besides the ignition switch that may be causing the problem. I took my bottom dash board panel off and haven't hooked it back up yet. There is a little grey box under glove compartment that was on the bottom panel dash board and had quite a few connections on it and I haven't hooked it up yet: Could this be part of the problem?

Abovetimberline

The ign switch is not the issue,but everything else you unhooked needs to be hooked up again. that little gray box is your trany control,when I unhooked mine it would not even move in drive.

HolyCow

Could be the problem. I use to know what a lot of that electronic stuff was for, like the grey box under glove compartment. I have forgotten most of it. I noticed my Jeep does not have the pick up it did have and the idle is terrible, and it seemed to happen right after I replaced the ignition switch. I had to take the lower dashboard off, I guess, maybe I didn't, to get to the ignition switch and drop the steering column. The other connections are mostly panel lights or dashboard lights. I hooked the ignition switch and dimmer switch up, except for that little grey box and the dash lights. So, I'll hook her back up and see what happens before I adjust or clean anything. Thanks!

HolyCow

Amazing! How this electronic stuff works. I hooked that little grey box back up and it solved the problem. Idle back to normal and the pick up is great. I thought that might have something to do with it. What does that grey box do and what is it called. Apparently it has something to do with the way it runs. The only other issue I have at the moment is after I put my steering column back together, my dimmer switch is sticking. When I flip it to brights it won't go back to low lights. I have to push against the arm next to the column to get it to snap back to low lights or regular beam, it will flip to bright, but not back to low beam without holding the arm as I hit the switch on steering column. I haven't tried adjusting it yet, there is some movement as it is hooked to the steering column as it rests on the ignition switch, so I may be able to move it a little, that may solve it. At the moment it isn't a big deal, but I need to fix it. Thanks!

fantic238

lol, you drove your jeep with the TCU unplugged, with only second gear...

HolyCow

Yea! And it drove like crap! But, it drove. It is a little colder now, my idle is better, much better, but only after it warms up a bit. I can't just put it in drive and take off, I have to give it a few minutes in cooler weather, I suppose. But it is much better and the pickup is great. Is there anything else I need to check. What is a TCU.

fantic238

transmission control unit

Abovetimberline

Cool it is fixed,the problem with your lights is more than likley the dimmer switch on the colum located on the left side,it is possible the connecting rod is not all the way in the slot,also you may not be connected right in the colum itself. The little black piece in the picture needs to be correct in the colum.
check the rod from the colum to the switch first.

HolyCow

How can the TCU (transmission control unit) effect the idle. I know it had to do with the pick up or drive, but after hooking it back up, the idle improved. There must be other connections on the TCU that effect the idle. Yea, I'll check the arm out on the dimmer switch before checking the little black piece in the column. Thanks. Very helpfull, and I'm learning. It's great to work on your own vehicle and save money, plus the know how is invaluable. Next thing, is new plugs and wires.

fantic238

Because it stays in second gear when you stop, and that slows down the engine RPMs.