dorkman52000

I searched but did not find a thread pertaining to my situation.....

Okay, I need a little advice on where to go from here. The other day I decided to take out the t/stat so that my S4 N/A would run a little cooler in the heat of CA. No problem, I've replaced the t/stat several times on these cars in the past so I know what I'm doing. It ran a little cooler but the idle was way high even after warming up to about 180 degrees (around 2K RPM). So, after driving it for a day, I decide that I can't keep driving like this and decide that maybe since the computer knows the car is running cooler that's why the idle is a lot higher.

I put the t/stat back in yesterday and now even though the car runs warmer again the idle has not dropped. So I figured it's the temp sensor that goes to the ECU located on the backside of the t/stat housing. If it is not sending a signal, then the computer will think the engine is cold, which is why it has the higher RPM, right? So I replaced that right now and the idle still does not drop even at normal operating temp (between 180-195 degrees). I did not touch anything else (TPS, etc...) so my question is two-fold:

1.) What the hell happened? The only other thing I know about the RPM/warmup process is that wax thermopellet inside the throttle body but I don't know enough about it to know if it is the culprit.
2.) What should I do next? At least my car runs fine, but sitting at stoplights @ 2K-2300 RPM sucks. I don't want to adjust the TPS or anything else until I figure out why this happened to me just from changing the t/stat.

Thanks for reading this thread, feel free to post if you have any suggestions/advice/ideas/SOLUTIONS

WAYNE88N/A

You sure you didn't damage or knock off a vac hose or any intake ducting when you pulled the t-stat?

My88Se

iTrader: (10)

Idle adjustment scrw on the Throttle Body? The one under the TB not the one on top of it. You should be able to mess around with that to get it to idle better, but you have to take the TB off to get at it.

rx7ryan

faulty thermostat??

dorkman52000

I don't think I knocked off a vacuum line because I can't see anything that is disconnected. I don't know of any vacuum lines that are near that area anyway, but I'm going to double-check in a minute. I've been busy all day so I'm going to get back at this thing now.

I'd rather not mess with the idle on the TB because I didn't touch it in the first place to make it run at a higher RPM. I will instead try to find something that could have been disconnected in the 1st place.

Thanks for the help guys. If anytone else out there has suggestions, then you're welcome to post here. I will update this with my findings once I have the damn thing fixed. Happy Father's Day to all you dads out there

rs_1101

try thermowax removal?

dorkman52000

Okay I checked all around the engine compartment and cannot find a single loose end (vacuum hose, wire connector, etc...) anywhere save for the wires that are supposed to be disconnected (e.g. the green one you ground when adjusting the timing).

I know it can't be the t/stat because this was occuring when there was NO t/stat in the car a couple days ago, plus it seems to me that the problem is occuring because of something located in the cooling system before it reaches the t/stat and radiator. That's why I immediately replaced the coolant temp sensor that goes to the computer for the engine.

During the course of today, the car now goes to 3K RPM like it should at startup, then drops down to 1500 RPM (lower than yesterday) but when I start driving and get to a light or something it runs at 2K or 2200RPM.

The wax thermopellet in the TB might be it, but why would it change during the course of time when I was literally taking out the t/stat? 20 minutes was all it took for me to drain the system, take out the t/stat, clean the surfaces of the housing, and re-fill the system. If removing the wax pellet in the TB is a solution, I'll do it if someone can point me in the direction of a write-up and a good reason why it may be causing the problem.

Again, thanks in advance for the ideas, but I think there may be something else at fault here that I'm missing.

WAYNE88N/A

How well have you bled the cooling system?

You need to verify that the thermowax is pushing the cam off like it should while she's warming up. Get a mirror back there and watch it...

dorkman52000

That's a good idea, but I don't know at this point what to look for. I am not sure of the location of this cam or what it looks like, so could you be a little bit more descriptive so I can check this process? I'll do that check when I get a chance tomorrow if you could help me out on that.

....If it is true that the cam is not moving due to the thermowax not moving it, what is my solution? How do I repair that? Do I just get another TB? I've never done this or heard of anyone else doing this, so your wisdom is needed here! Thanks for the help, I'll talk to you guys tomorrow.

dorkman52000

bump, anyone? Not exactly sure what I'm looking for here, could use some help so I can check this out and eliminate the problem. Thank you

WAYNE88N/A

Man, everybody must be on vacation, I came back over a full day later and no one's told you where to look, lol...

All right, man, on the back of your throttle body is the input bellcrank from the throttle cable. Grab a mirror-see it? Good, now connected to all that crap back there is your fast idle mechanical system. There's a decent picture of what you need to be looking at in the Haynes and FSM manuals.

You need to start the car cold, and watch the thermowax & fast idle thingy.
A little cam should ride along the edge of the bellcrank plate, then drop off into a notch area (it's at this point the engine should idle down to 750 rpm).

If nothing's moving back there, suspect a bad thermowax (or cooling system plumbing feeding the wax).

If everything is moving as it should, you have other problems...

dorkman52000

Cool thank you wayne I'll check it out ASAP. I would do it tomorrow but now I have a serious electrical problem and my FC won't start at all or turn on any lights, radio, etc. I borrowed my roomate's FB and drove my alternator and battery down to AutoZone and tested both myself (I work there so I know what I'm doing) and both are in excellent condition.

ALL fuses are good; and I think (just a hypothesis now) that I may have a bad CPU? I can jump the car with cables and it starts right up. But when I turn it off and immediately turn the key forward to re-start, nothing works. The door light doesn't even come on when I open the door.

So, tomorrow I have a prior engagement modifying the roll cage on my race car or else I can't race Friday night (and tomorrow's the only full day I have off till then), and if I have time I'll work on the FC and try and track down where my power is getting interrupted. I've never had any electrical problem like this before, so I am kind of frustrated but I'll find out what's causing it.

Thanks for helping me out, I will update this as soon as I find out what my car's two problems are.

Cybaster

ok ok, try this.... use your foot to lift the gas pedal.... does the idle drop?

that just happened to me TODAY, while i was re-wiring my electricals...
the idle was at 2k for the whole day.... until i accidentally lifted the gas pedal, so i knew the throttle cables were stuck...
so i found out that the throttle cables were moved too much and it caused them not to go back to their original position.... so check that out =D something that I completely ignored.... see if that work

dorkman52000

Been there, done that. That's one of the first things I thought of because it seemed to me that nothing else was affected. My gas pedal is tight when I lift up on it, and the other end where it connects to the TB won't move very much either (not enough to drop the RPM by more than 100).

Thanks for the advice though, it was a good idea. I've been working on my race car for the whole day, so I haven't had a chance yet to work on the RX, but I'm going home now to do so.