I need some big time help here....

I was reading a post about a guy who's problem was almost dead on to mine:

http://www.naxja.org/forum/showthread.php?t=29662&page=1&pp=15&highlight=tps

I have a 1997 4.0 4dr automatic with 77,000 miles and it was doing the same thing: "Everytime I would start up the vehicle it would run for a few seconds and then it would start to sputter, make a couple pops/clunks under the hood like it wasn't mixing fuel right or getting enough gas. I could floor it and it would still do it, till it cleared up after about 5 seconds and would be good to go. It would only do this at idle and low take-off speeds."

I replaced both O2 sensors, added new exhaust, plugs, rotor and cap, wires, battery, etc. I even bored out the TB and added a bored out spacer thinking I was having bad combustion issues and wasn't getting enough air, but it still did it and still showed an engine light that kept pulling heater circuit codes for front and back.

So yesterday I was at a light turning right to head to my place and all of a sudden it wouldn't go. The engine was running and I had it in automatic but it wouldn't move. The engine would rev but no luck at all. So I put it into the "1/2" gear setting and it worked fine. I went to bed, got up this morning and it ran fine for about 5 minutes and then did the same thing. So I went and had the transmission level checked. The fluid was brown but full. Then I took the advice of someone who told me to check my fuses, which I did and the only one I found popped, was the same fuse you told the guy was told about in the post above about regarding the o2 heater circuit which I was having the same issue with.

So while I was replacing that fuse I also was tightening down a sensor on the left side of my throttle body (if you are looking at the engine from the front). When you unscrew it this sensor, it looks like a small rod. Well, the rod was dirty so I cleaned it off with some TB cleaner, then plugged and screwed it back in. I then hooked the battery back up and went to start the jeep. Well...I put it in gear and pressed on the gas and the sucker almost bogged down on me...and then it did and died. Turned it back on, tried reverse and it worked great, but put it back in auto...even the "1/2" gear and it bogged and shutdown. I restarted it in park, put it in neutral and reved the engine...no problems....except I noticed that none of my gauges were working, rmps, fuel, battery, etc...none of them. I thought maybe I had not put a fuse back in correctly after going through all of them, so I took them out and put them back in again....same thing.

Could it be the sensor I cleaned (if so, what sensor was it?) Could it be my TPS possibly. I don't think the transmission has ever been flushed, could it be that? Could be the fact that the heater circuit for the O2 sensors are now working?

What do you all think or what should I try?

Thanks,

Chris

I think the sensor you cleaned was the idle speed motor (also called IAC, idle air control, etc.). That and the thing to the right of it (the TPS) are very suscpetible to failure when cleaning.

I would check to see if your TPS is adjusted right. Do a search on how to do this.

Okay, I got a picture of it...what is this sensor with the red arrow pointing towards it? This is the one I pulled out and cleaned and looked like a prong. Also, what is the sensor to the right of it, is that the TPS?

http://f1.pg.photos.yahoo.com/ph/beebech/detail?.dir=/43d9&.dnm=5f9f.jpg

If this is the IAC that I cleaned and ruined, what is the best way to replace it or fix it? Would that cause the entire instrument panel to not function (i.e. gas gauge, rpm, speed, volts, etc)?

Thanks,

Chris

Looks like your throttle body is situated differently than my 87XJ. But that definitely looks like your IAC motor.

Replacing it is pretty straightforward. Unplug the connector, unscrew the old IAC and put in the new one. No adjustment that I know of.

The pintle (small rod thing) in the IAC is the thing to be careful about. Cleaning shouldn't really harm the IAC. Pulling on or damaging that pintle will. I had a bad IAC and it was the pintle that was broken.

As far as the gauges, the IAC shouldn't have anything to do with them going out. Isn't there a fuse for the instrument panel? Have you checked that?

The IAC is not normally sensitive to cleaning, the TPS however is. I hate to see anybody just go and buy an IAC since they are spendy and are seldom defective in my experience. Do you have a buddy you can swap IAC's with for a few minutes? Sure beats blowing the $$$.

Okay, I will see if I can swap out my IAC with someone and I know there are posts for checking the TPS, but what is the best way?

Regarding the gauges, do you all have any idea which fuse controls the instrument panel, because all the fuses are working and not blown, could be one is just not in correctly.

Chris

Definitely don't shell out for a new IAC unless you know it's bad. They are pricey even at Autozone. Old_Man's advice would be the way to go. See if you can't swap it out with a known good one.

What do you mean pull the pintle or broken pintle? How do you know if it's broken on the IAC? Because when I was cleaning it, I turned the sleeve that went around the pintle, etc. Does that do anything?

Chris

Double Down said:

Okay, I got a picture of it...what is this sensor with the red arrow pointing towards it? This is the one I pulled out and cleaned and looked like a prong. Also, what is the sensor to the right of it, is that the TPS?

http://f1.pg.photos.yahoo.com/ph/beebech/detail?.dir=/43d9&.dnm=5f9f.jpg

If this is the IAC that I cleaned and ruined, what is the best way to replace it or fix it? Would that cause the entire instrument panel to not function (i.e. gas gauge, rpm, speed, volts, etc)?

Thanks,

Chris

Click to expand...

THE SENSOR THAT THE RED ARROW IS POINTING TO IS THE AIR IDLE CONTROL VALVE. THE OTHER ONE IS THROTTLE POSITION SENSOR
in the power control box there are three rows of mini fuses between the relays and maxi fuses-----9-13-17
10-14-18
11-15-19 <<
12-16-20
check # 19-- 15amp. blue badge 714 [email protected]


97 cherokee sport 4.0 k&N MSD Coil- MSD 5200 ignition pac.
1959 cj5 restored frame up jeep v/6 240 hp.

Double Down said:

What do you mean pull the pintle or broken pintle? How do you know if it's broken on the IAC? Because when I was cleaning it, I turned the sleeve that went around the pintle, etc. Does that do anything?

Chris

Click to expand...

When I cleaned my IAC last week and put it back on, it idled very high. Took the IAC off again, and the thing fell apart in my hands.

There's a small screw at the end of the pintle. This came completely out, along with the sleeve you mentioned, and the spring.

I thought I was screwed. But I carefully put it back together and made sure that the pintle moved smoothly. Now it runs perfectly.

I guess what I'm saying is - check that screw at the end of the pintle.

Okay, I will check the spindle and see if I can fix it or not and I will check the fuses again.

As to your question. The sleeve (which I believe was plastic?) on my IAC was cracked and so the spring and pintle rod were loose and fell apart when I unbolted the IAC.

Are you still dealing with the bogging down problem or is it only an instrument panel issue now?

Haven't fixed/checked out the IAC yet, but I am going to do that after work and check all the fuses at the same time. The IAC is the only I can think of that I changed or messed with. The only other thing I did so far was to replace a 15 amp fuse that supposedly was for the O2 heater circuit that I kept getting a check engine light for. I can't imagine that changing the fuse to actually make it work would do that much....would it?

Just for giggles, when I did replace that fuse which now let's the O2 sensor heater circuit work, what exactly did i do?

Thanks,

Chris

Okay,

So I just went through all the fuses in the engine and regular fuse box inside the cab. Nothing was blown. I unscrewed the IAC thing and here is a picture of it:

http://f1.pg.photos.yahoo.com/ph/beebech/detail?.dir=/43d9&.dnm=2951.jpg

The crazy thing is that if you push on the top it pushes down inside the black piece. So I messed with it as much as I could, made sure it was working and then put it back.

Then I pulled every single fuse and put them back in...here is my engine fusebox:

http://f1.pg.photos.yahoo.com/ph/beebech/detail?.dir=/43d9&.dnm=d59a.jpg

Now here is where it gets interesting again.

I started my XJ and noticed now that all the gauges except for the oil pressure gauge, speedometer, and rpm were working. So then I put it in reverse and it worked fine....THEN I put it in auto and tried to go forward and I swear it was like all the brakes were on, because it labored really hard and then died. So I started it again, put it in reverse and everything was fine, so I decided to put it in the "1/2" gear setting and it did the same thing as the auto settings.

Then I turned off the Jeep and turned it back on again...NONE of the gauges were working. I then waited for a sec and then turned the Jeep back on and the same 3 gauges were working. :huh:

What the heck is going on here?

I can possibly understand that the gauges are faulty because of a fuse not being inserted correctly, etc but what gives with the transmission?

I decided to crawl underneath to see if I could see anything and the only thing I saw was this thing on top of the transfer case/transmission (not exactly sure what it is):

http://f1.pg.photos.yahoo.com/ph/beebech/detail?.dir=/43d9&.dnm=7bb4.jpg

But I was thinking that this thing has to have a fuse somewhere and if so, could that be part of the problem...actually, what the heck does it do? :dunce:

I can't go anywhere or do anything till this thing is fixed, so whatever you guys can do to help would be great.

Thanks,

Chris

Damn. That really is perplexing. I wish I had enough experience and knowledge to direct you towards solving it. I've re-read your posts several times and a common denominator hasn't become clear to me yet. Unless something electrical went screwy when you were cleaning the IAC.

Anyone else wanna take a stab at this?

Double Down said:

I decided to crawl underneath to see if I could see anything and the only thing I saw was this thing on top of the transfer case/transmission (not exactly sure what it is):

http://f1.pg.photos.yahoo.com/ph/beebech/detail?.dir=/43d9&.dnm=7bb4.jpg

Click to expand...

That's the speedo gear - probably has nothing to do with your problem.

check all your grounds in the engine compartment

can you tell if you have any stored codes now? i'm thinking it has something to do with the engine pulling the wiring while in drive. in reverse the engine is torquing in the opposite direction. i wuold chech the crank sensor wiring. try pulling the crank sensor wire while the jeep is running and see if it duplicates the problem.

How can you tell if those big black fuses are blown in the engine compartment? Those are fuses right? What do they have to do with anything?

http://f1.pg.photos.yahoo.com/ph/be...9&.dnm=d59a.jpg

I am going to check for codes, but everything is fine except for when it dies when I try to go forward and then it throws a check engine light, but that goes away the next time you start it.

Also, my airbag light is on now, probably from me taking out and looking at the fuses. Nothing is busted, but could it be possible that the fuses have been in there so long that they might need some cleaning? Or maybe the fuse box connector itself? How would you go about making sure that the fusebox connections for the fuses are clean contacts?

Thanks,

Chris

Where is the crank sensor wire...can I find it's location in my Haynes manual?

Chris