Bad idle when its cold.. fast idle when its hot.

[Ecomike]

Alright well that's forsure me problem.

I'm positive the bolts were tight, however I will be buying some new ones as the heads on mine are stripped. What size are they? The napa said they didnt have any, and said its a special size 4 thread 75.

Also already ordered the new TSP! $50ish which is really good compared to $227. Thanks for that link! Where did you buy yours from?

The new one I got from teamCherokee.com came with 2 new bolts, lock washers, and flat washers. It was about $37.00 delivered. , and it was the automatic transmission version TPS with 2 pigtails. It was an OEM one. I am guessing they bought out the chrysler inventory on them or something as all the aftermarkets ones were like $65 to $165. And for some odd reason the Manual tranny version was even higher, but we already discussed that, right? They may not be that cheap for much longer!!!:rattle:

 

[mattbred]

Oooh awesome! That's the exact one I bought.

Second one down here:
http://www.teamgrandwagoneer.com/cgi-bin/partsSQL/search.cgi?query=tps&catid=95

How long did it take to get to ye?

 

[mattbred]

two weeks later, no tps.. not even an email giving me a tracking number. only the automated email. also sent an email to the guys and never got a reply back.

Also I have an update on my situation:

When I start my jeep, it'll do the normal rev-to-2000, but now instead of dropping right away, it'll keep those RPM's for two seconds or more and then drop.

Any ideas?

 

[Ecomike]

two weeks later, no tps.. not even an email giving me a tracking number. only the automated email. also sent an email to the guys and never got a reply back.

Also I have an update on my situation:

When I start my jeep, it'll do the normal rev-to-2000, but now instead of dropping right away, it'll keep those RPM's for two seconds or more and then drop.

Any ideas?

I got mine in 5 to 7 days (apx) as I recall. Have you called them? at (262) 658-2268

2 seconds is not bad. I had much worse than that for years before I replaced the TPS. Mine would high rev for 3 to 10 seconds.

 

[mattbred]

That would be pretty long distance I would think. Havn't called them yet.
Did you get another email besides the automatic one? IE one that says it's been shipped, or the UPS number etc.

I got mine in 5 to 7 days (apx) as I recall. Have you called them? at (262) 658-2268

2 seconds is not bad. I had much worse than that for years before I replaced the TPS. Mine would high rev for 3 to 10 seconds.

 

[Ecomike]

That would be pretty long distance I would think. Havn't called them yet.
Did you get another email besides the automatic one? IE one that says it's been shipped, or the UPS number etc.

Not sure, all I could find was an account acknowledgement email and an order acknowldgement email the same day.

I use my cell phone (sprint nationwide minutes) for those calls.

I suggest you check all the details on your order, email address, physical address, and the email address you used to recontact them with the order inquiry and look for an error, and go to their web site and contact them through their web site with a fully documented order inquiry, including their order acknowledgment number, date of the order, etc. You might also look for a fax number and fax them the entire detailed enquiry (saves on the phone minutes!!!).

I checked the box, and my emails, and I could not determine how long it took to arrive, but I am thinking it was less than 2 weeks.

 

[redrider2911]

i have the same problem with my 87 wagoneer (xj body style) 4.0 HO Ive tried all the same things u have and none worked either

 

[Ecomike]

i have the same problem with my 87 wagoneer (xj body style) 4.0 HO Ive tried all the same things u have and none worked either

Have you replaced the TPS?

Have you verified that there are ZERO vacuum leaks!!!!

 

[mattbred]

Got the new TPS, set it to 0.82, and it hasn't fixed any problems so far. It's definitely something else.

 

[Ecomike]

Sorry to hear that. All that leaves me with is a small intermitent vacuum leak that when cold comes and goes causing the bad idle and that grows to a steady vacuum leak when hot, especially since you already sealed off the EGR port.

I will try and read over all this again in a day or so, get a fresh perspective, but for now this one has me too.

If you don't need a spare TPS you should offer it to some others here needing one in the for sale forum.

I just rechecked our last conclusion from the idle repeatability test, and I just don't see how the new TPS could fail to solve that problem, unless the TPS is not bolted down tight itself? Is the throttle body damaged, or the threads stripped on the body, or something in the linkage keeping the TPS idle from getting back to same spot each time????

 

[mattbred]

Nope, TPS gets back every time. I'm going to take it for a drive and see if the +1000 RPM idle returns. That's the one thing I am hoping the new TPS fixes.

 

[Ecomike]

So it fixed the variable TPS idle voltage (or resistance) after repeatedly excercixing the TPS sensor, but did not fix the rough cold idle nor the hot high idle? Those are and were the last problems left to fix right?

Nope, TPS gets back every time. I'm going to take it for a drive and see if the +1000 RPM idle returns. That's the one thing I am hoping the new TPS fixes.

 

[mattbred]

Mostly. Sometimes it will return to a different voltage. It depends if you do it really fast or slowly. It's odd, but I've tried 3 different TPS's and they all do it. It definitely feels smoother and has a better spring than the others, so they were old. Definitely good that it wont cause FUTURE problems, but I want my present problems fixed.

So it fixed the variable TPS idle voltage (or resistance) after repeatedly excercixing the TPS sensor, but did not fix the rough cold idle nor the hot high idle? Those are and were the last problems left to fix right?

 

[mattbred]

I still have a high rev up on startup too. I tried switching the O2 and Power latch relays and there is no change. I believe what is happening is it's getting too much air somewhere, and the IAC slowly sets the idle down. When it's warm, perhaps the leak gets larger and the IAC can't comensate.

Now, where to find that leak is the problem. Most likely on the intake, man what a pain in the ass that would be.

 

[Ecomike]

When it is warmed up, and you restart it, does it ever slow down to the correct idle speed or is always a high idle once it is warmed up?

I still have a high rev up on startup too. I tried switching the O2 and Power latch relays and there is no change. I believe what is happening is it's getting too much air somewhere, and the IAC slowly sets the idle down. When it's warm, perhaps the leak gets larger and the IAC can't comensate.

Now, where to find that leak is the problem. Most likely on the intake, man what a pain in the ass that would be.

 

[mattbred]

Once at fully operating temp, it's initial startup RPM is 900-1000. After driving it, it's 1200-1300. After driving then pumping the gas real fast OR restarting it, idle goes back to 900-1000.

When it is warmed up, and you restart it, does it ever slow down to the correct idle speed or is always a high idle once it is warmed up?

 

[Ecomike]

Once at fully operating temp, it's initial startup RPM is 900-1000. After driving it, it's 1200-1300. After driving then pumping the gas real fast OR restarting it, idle goes back to 900-1000.

Once its hot and somehow gets to 900 rpm immediately disconnect the IAC and drive it that way for awhile. If the idle does not change and stays at 900 rpm all day, it is a sticking IAC or IAC wiring issue. If the idle still varies with the IAC disconected then it should be a vacuum leak coming and going.

To be sure, if the idle still varies (goes up) after disconnecting the IAC at 900 rpm (warmed up engine), then disconnect the O2 sensor also so that the Renix ECU can not vary the A/F ratio, it will be forced to use a static table. Then if it still has a variable idle it must be a vacuum issue somewhere.

 

[mattbred]

Alright I'll try it.

I DID disconnect the IAC while it was idling at 1200-1300 and restarted it, and the idle went back to 900.

 

[mattbred]

TPS didn't fix ANTHING.

I still get 1300 RPM idle after driving that goes away if I tap the throttle or restart the jeep. I'm not sure where to go from here.

 

[Ecomike]

TPS didn't fix ANTHING.

I still get 1300 RPM idle after driving that goes away if I tap the throttle or restart the jeep. I'm not sure where to go from here.

You may have already done this, but all that leaves that I can think of is to pull the throttle body, clean and inspect it and the throttle linkage, then replace the gasket, lube the linkage and throttle plate assy in the throttle body and try it again, or try another throtle body even?

If that fails I would pull the Intake manifold, clean and inspect it...etc.

But before you pull the manifold, are you sure you have looked everywhere else for a vacuum leak?

Thay can be just about anywhere, A/C damper door control hoses all around the dash, brake booster, cruise control, loose valve cover tied to the CCV vent hose system, the CCV hoses and grommets themselves, the vacuum line to the vacuum bottle, and the bottle inside the front passenger side bumper, there are a ton of little of plastic vacuum line hoses all over the place under that hood. I found one the size of shot gun shell, up under the rain gutter of the firewall near the center of the Jeep that was huge, found it by accident one day. A small leak in any one of them can be causing the high idle.