starts and drives, but won't idle

[wingman]

I just encountered this problem today after a short period of boosting. It will start, but will not idle...when it initially starts the revs go to 1K, then fall immediately down to zero intstead of 650-750, no studder or nothing it just plummets. Since the motor will run perfectly fine when the throttle body isn't closed I suspect the ISC system took a dump on me...but what else could cause this symptom? I'm guessing fuel pressure would have something to do with this, but it hasn't changed since I used it to solve a few rough idling problems. I'm not too keen on an AFPR install, but does it still use the fuel pressure-up VSV? Would that cause the condition that I'm having?

I've already checked all my vacuum lines, and they all appear to be fine...but I wouldn't think a vacuum leak would kill the car at idle. If I were to unplug the wires going to the ISC would it idle high, if at all? I've got a spare ISC valve sitting here that me and a buddy will be putting on tomorrow...if that doesn't solve the problem I'm looking for other reasons as to why it won't idle.

 

[wingman]

ok just got the ISC swapped and replaced the FPD (it was leaking) and it still wouldn't idle...but I took it out for a drive, boosted it, and it was fine. Dunno what that was all about, possibly the ECU changing something, but I'm hoping it still works from here on out, if not I'll give an update.

 

[aye mate]

Check your codes. I'm gonna say AFM.

 

[SP 7M]

I just had the local Toy dealer diagnose a bad ISC valve. I dropped off the parts yesterday and hopefully that'll solve the problem. Yes, I could install it myself but it's already there and if that doesn't happen to do the trick then at least it's still in their hands.

The problem my car had is that it wouldn't idle when it was cold. It would surge a couple times and then die. Once it was warmer it was decent but it still has some surge to it at times.

What I want to be accomplished by the dealer (this is only the second time it's been there in the 3+ years I've owned it, btw) is to get it decently driveable. I'll probably keep it out here in HI a little longer until my Lexus is fixed (coolant leak from a possible cracked head) and then pay to ship it home in CA.

My dad deals with a master tech with his own shop exclusively now for his Supra and he wants me to have my [difficult] work done there, too. I'll have him install my SP61GT, fuel pump, AFPR, MAF-T and re-install and tune my Apex S-AFC. I'll also probably get a DDP and have a wideband kit installed as well. I'm sure that if my Supra gets to CA by July that this guy will have plenty of time to get it all set for me when I get back in October. My modest power goal is 400/400 at the wheels. I'm sure that'll be more than enough to scare me for a while.

I could wait until just before I leave here permanently in October to have it shipped for free instead of $800-$1000, but I'd rather get all of the work it needs out of the way.

 

[wingman]

Check your codes. I'm gonna say AFM.

no AFM code...I got 51, which I expected because there is no A/C and I also got 22 which I have since taken care of. Cleared the codes and after that all I had was 51.

The idle is very rough now, but it doesn't die...it just jumps between 450 and 700. I'm going to mess with the FPR a little bit and see if that'll help it.

 

[fastazzsupra]

My 88 turbo is having the same problem, sorta. I was told by a toyota friend to check my ecu for burnt spots on the circuit boards. While checking it out I found dirt or something like it in the connectors for the ecu. I have not tried to clean it yet , but will on monday. Look at yours and see. I'll let ya know if it fixes mine. Hope this helps. Let me know what you find out.