Hi All
The forum has some good energy and knowledgeable people on it these days, so let me put this out there so I can benefit from your expertise.

I've had my AW11 for 26 years now, and back in '98 imported a Levin front cut (early AE92 w/AFM and DLI) and swapped in the GZE.

I've been chasing an issue can't get to the bottom of. Essentially, it'll run fine for a while then stumble and die at idle. It runs fine at anything over 2000 rpm and runs fine under load.

I've tried 2 different ECU's, 2 igniters, and 2 coil packs. The only ignition piece I don't have a spare of is the crank angle sensor. I've had the AFM rebuilt and recalibrated. Still the problem persists.

I finally brought it to a shop where a really dedicated young mechanic is doing all he can to find the issue. Because of the abruptness with which it quits and the fact that it's as likely to happen hot or cold, Jason (the mechanic) is pretty sure it's ignition related.

I really miss having my car run right. Any thoughts?
Thanks, Mo

At what rpm does your car idle ? Hot ? Cold ?
After it quits, does it start up right away no problem if you crank it ?
Have you tried winding the idle up to see if there is some idle rpm
above which the engine always stays running ?

Cheers... jondee86

Hi Jondee
Idles at about 1600-1700 cold
I've got the warm idle set high at about 1200
Yep, tends to start right back up when I crank it after it stalls.
Haven't wound up the idle setting, but if I manually control the throttle (at stoplights or whatever) I need to be over 2000-2300 to keep it running.
Thanks, Mo

OK. I don't have a GZE and have never worked on one, so I'm just going to
throw in a couple of possibilities... long shots

Normally aspirated 4AGE's have a IDL switch in the TPS that changes state
when the throttle goes fully closed. This signals the ECU that the engine should
be idling (not driving/running), and the ECU adjusts the fuel and ignition timing
to improve the idle. If you adjusted the idle speed via the throttle stop screw,
you would have needed to re-set the TPS to get the IDL switch to operate as
it should. Failing to do that will make for an unstable idle.

I believe (but can't verify) that the IDL switch may also play a part in the hot
off-throttle (anti-stall) strategy of the ECU. This strategy is designed to
counteract the tendency of an engine to stall when coming off the throttle at
a stoplight. Again it has to do with the ECU making fuel and ignition adjustments.

Another possibility that I have read about, but not experienced, as I have never
had an AFM engine, is the mounting position of the AFM. This (LARGE) pic
shows the factory orientation for the AE92 GZE AFM....



Apparently, it is possible to mount the AFM at an awkward angle (possibly
angled down) such that gravity or accel/decel forces can cause the flap to sit
too close to the "closed = no airflow = fuel pump off" position. Might be worth
reviewing if you were cramped for space in the AW11

Cheers... jondee86

Hi Jondee
By the way, I'm including Yoshi from Matrix and Gerald St. Agustin (TRD, an early pioneer in twin-charges AW11's and the guy that wired my car way back when) in these conversations.

I went to the shop to check on Mister Two yesterday and there it sat idling perfectly at 900rpm. It has been doing so for several hours a day for a couple of days now. We're happy that it is running right, but frustrated that we still haven't found what caused (or is causing) the problem. Here's a note from Jason with a diagnostic graph attached. You can respond directly to me via this forum and I'll forward any info along to Jason.

I wasn't aware of the IDL switch in the TPS, and Jason and I never discussed it, but I printed out your post and we'll check into it Monday.
Many Thanks!!
Mo
PS: Don't know how to resize the graphic of the scope reading, but I can email it to you if you want to see it. I'm at skyrider9@comcast.net

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Hi Jondee, as Mo has told you I've been going round and round with his MR2, trying to track down his mysterious ignition fault. It will randomly cut out and stall, like a clean ignition off. Swapping ECU's and or Ignitors got me no where. I've checked all the wires in that circuit and did find a shorted wire but repairing it only temporarily made a difference. The car goes through phases where it will act up all the time and then other times it will be flawless. I've had a close eye on the cam sensor but I have not been able to truly catch any faults. It's resistance readings go slightly out of spec when it gets hot but the specs are to be read at room temp, so my hot readings might be nothing to worry about. The picture I have attached is of my scope readings of the IGT and IGF circuits, I noticed the IGT reading on top is very clean and uniform as where the IGF reading on bottom is much more crude. I'm curious if you know if that sounds or looks correct?

Chasing intermittent faults can be a pain. I have just been thru the process
myself where I was having a total loss of the Ne signal and no start, but only
on some days !!! Other days it would start and run perfectly. Turned out to be
a soldered join in the signal wire.

The IGf signal is generated in the igniter from the coil flyback voltage so I
guess the shape will depend on the degree of signal conditioning applied. The
ECU will kill the engine if it does not see the IGf signal for a specific number
of IGt sgnals... that's about as much as I know. Other than that you need to
make sure the outer case of the igniter has a good ground contact, as it
grounds thru the case.

The operation of the igniter is a little unusual, as instead of the ECU sending
two phased IGt signals to a normal two-channel igniter, it sends one IGt and a
separate signal that instructs the igniter which coil to fire... sometimes
described as a "flip-flop" circuit. If the engine can idle happily for hours, then
it would seem that all circuits are working normally right up to the point that
the engine stalls

Cheers... jondee86