OK got a question for everyone here. I searched and searched and cant come up with anything. First off my car is non-sequential, fully done the right way. I'm running a PowerFC, 3" DP, 3" resonated MP, 3" catback, 2 intake pipes w/ K&N filters, and thats basically it.

A while ago I lost one of the TPS screws and slowly but surely the TPS kept moving and the idle was all over the place. Every once in a blue the car would stall all by itself if it wasnt warmed up to about 65*C, but it was very rare that it would stall. Lately though it was getting alot more frequent so I bought the other TPS screw and redid my idle from scratch. This didnt help so I reset the PowerFC thinking everything would be fine, still no good. Now its to the point that if the car isnt at about 83*C it will stall EVERY time I go back to neutral. After driving for a while it wont be as frequent unless I'm either parallel parking or just revving up slightly over and over like in traffic. Yesterday the car stalled on me 8 TIMES STRAIGHT.

 

Yesterday the car stalled on me 8 TIMES STRAIGHT while parallel parking. Today I started driving lightly when the car hit 65*C on the PFC and the car stalled at every stop sign. When the car isnt stalling the tach drops all the way to 500rpm and under and then quickly jumps back up to 850rpm. Then other time it will just drop straight to 800 or so like nothings wrong. Its really annoying and embarassing at time when it stalls over and over while parking. Help me out please guys. Thanks.

 

Ill tell you what I have learned before arghx (I think thats his name) gets in here and tells you the same thing. You need to adjust the F/C settings on the PFC, most likely raise them, this controls the RPM where the ECU starts cutting fuel on Decel. If its stalling during decel and short throttle movements then that is most likely where your problem lies. Adjust them in about 20RPM increments untill the problem is solved.

 

Also, you can try adjusting the dashpot and make it contact the throttle earlier. I have advised people to loosen the dashpot in some cases of idle sticking (the opposite of what I'm telling you to do here)--that doesn't apply to every car. I've found that the dashpot does help with the problem of stalling while trying to park in many cases. It's tricky to get it all dialed in just right. Sometimes adjusting the fuel cut settings isn't enough, sometimes adjusting the dashpot isn't enough. Sometimes you solve a stalling problem and create an idle sticking problem. It can be time consuming to sort out. Aggressive clutches combined with lightweight flywheels make stalling more likely to occur and idle stability harder to achieve.

There's no one surefire adjustment that works on every car, simply a method or a list of strategies to try when troubleshooting.

 

YES! I got your name right! Haha I should have thought about the dashpot! I've read through your idle threads enough times.

All Hail arghx, King of the idle!

 

I'm having almost the exact same problem at the moment. I'm running a microtech lt-12 though. As a temporary solution, I turned my idle up to 1050, which has worked so far, but I need to go back and look at what is actually causing the problem. If you get it figured out, let me know how you went about it.

 

Thanks both of you. I read through arghx's thread earlier while searching and adjusted the F/C value a little bit but I loosened the dashpot until it didn't touch the throttle anymore. I'm going to have to get back at it later today after work. It's just weird that the car used to idle perfect and now suddenly wants to act up. The life of an FD owner I guess.

 

yeah I went and updated my other thread. I just want to make it clear that loosening the dashpot completely shouldn't be done on every car, I may have created that impression previously.

 

Check your clutch switch is OK. Look at the switches on datalogit (if you have it) to see if it toggles.

I had a problem like this where the car would stall in low speed manoeuvring & I must admit that I thought the same as you do that it was when I went to neutral, I did all the idle relearning/set up etc. to no avail. I finally twigged that it would stall if I declutched, but didn't immediately get it into neutral, I was being sloppy in my observation.

Got a new clutch switch & bye bye to the prob. I checked my old switch & the spring had broken, I could have just replaced the spring, but it's only about a $15 part.

Hope your prob is as simple!

 

jhaywood, that has to do with the fact that the ECU doesn't attempt to control the idle as much while the car is either in gear or the clutch is depressed as it is set up to believe that the driver is in control of the throttle in this situation. that is where the idle bleed screw, and the other manually set idle settings come into play. The fact that the spring failed means that more than likely once the clutch was depressed the switch was stuck in, sending a constant signal to the ECU that the clutch was depressed, hence the crappy idle (You more than likely didn't need/want to know all this, but I decided to include it for others that might come across this thread during a search)

 

Hi rotordream, actually it's the other way round, with the broken spring it never sees the clutch as being depressed (as the switch is open when the clutch is NOT depressed).
I absolutely agree with you as to the behaviour of the ECU in this situation - it does not go into an idle control loop. In normal driving where the clutch is in for a short time this is fine, but for low speed manoeuvring where revs drop into the idle area causes problems.
I was just pointing out something that I missed during my troubleshooting of a similar problem Of course, this may not be the same prob at all, but it's an easy check!

 

I cannot remember exactly, but with the clutch depressed doesn't the plunger get depressed? and once released the spring pushes the plunger back out? or is it the other way around? when the clutch is released the plunger gets depressed?

 

The switch normally has the plunger depressed by the clutch pedal, breaking the contact. When you press the clutch the plunger is allowed to move out of the switch body, operated by the spring (if it's not broken ), making the contact.

 

Hmmmmm that seems strange to me, because that is how the brake switch operates, and IIRC (Which I apparently don't) they operate in opposite ways. Oh well, Ill have to go check that out! (Not doubting you, just curious)

 

They operate in the same way (circuit closes when the pedal is pushed), but the read point in the circuit is different so PCM i/p 1Q pulls low when the clutch is pressed & 1S pulls high when the brake is pressed. (See pages Z-34/Z-64 for circuit & Z-37 for logic)

 

the clutch switch only applies to starting.

the dashpot helps the car return to idle when you get off throttle.

the mechanical throttle body settings can play a part in how steady your engine idles and effects the open/closed readings the TPS sensor sees.

Given you lost a screw on your TPS and it worked fine before, I'd say you still don't have it set correctly.

 

I had the exact same problem and it ended up being the clutch switch (not the big white one that it used to start the car). There is a switch near the top back side of the clutch pedal also that goes bad. You can either buy a new one from ray or replace the spring with a ball point pen spring. If you search you will find threads about it.

I did pretty much everything you did and adjusted the apexi but nothing worked. The car would stall every time I came to a stop and threw it in neutral if I didn't rev it or it would drop to about 500 rpms and shoot back up if it didn't die...
It took me 5 minutes and pulled out the switch and replace it with a new one for about $20 and now the car is fine with all the old settings.

 

There are two clutch switches, one is the starter interlock switch, that inhibits starting unless the clutch is depressed, & one signals clutch use during normal operation, "the clutch switch".
The clutch switch impacts idle control & a whole lot of other stuff, see the relationship chart in section F

 

^understood on the clutch switch. didn't think it played that big a role on idle since that is one of the few original parts still on my car... i still doubt that would be the cause of the OP's problem.

 

I was bout to say cause my bottom clutch switch is bypassed with no issues of that sort. Didn't know there was another one though

 

When the spring in my clutch switch was bad, my idle fluctuated terribly whenever the clutch was depressed. Sure enough, after finally removing the clutch switch I found the spring to be broken into three pieces. Replaced the spring and the car idled like a champ.

When the spring was broken the idle did drop and raise itself repeatedly, but I don't recall ever stalling because of this.

Just thought I'd throw in my own car's symptoms to help the OP decipher what the problem might be.

 

My idle doesnt fluctuate, its only a split second on decelleration, only when I go to neutral. I'm going to try to mess with the PowerFC this weekend and see if I can fix it, if not I'll try the clutch switch.

 

When my clutch switch went out, my engine would die when I was cruising and pushed in the clutch. I never tried putting it in neutral though. I tried playing with the powerfc, but no matter what I did, it would still die.

I'd say go ahead and check the switch. You don't even need to take it out to check it. Just wiggle under the dash, so you can see the top of the clutch pedal, and push it in with your hand. The plunger should come out about an inch or so. Mine only went out about half an inch.

 

you have a power fc, just go to sensor check and see if the CLT lights up when you push the clutch, go do it and stop posting here, it will take 5 seconds.

I also beleive this is your problem.