'88 Formula with a '93 3.4L DOHC, '93 ECM OBD1, 5 sp
Starts fine, idles fine, runs fine until you disengage the clutch when downshifting. Then the rpms drop to the point that the engine wants to die. If you can do a 2 foot/3 pedal shuffle fast enough you can usually get it out of gear to brake with the left foot to put your right on the gas to catch it before it dies. If you do then it idles fine.
I have an ALDL cable correctly configured for the '93 ECM OBD1 ALDL conn on its way. When it gets here I'll run some logs for Ryan at Sinister to look at. He tuned the original install.
Until then anyone with ideas, things to check, etc.?

maybe vehicle speed sensor?

Check to see that the ECM is seeing the VSS vial the ALDL cable

Does the engine idle faster cold and slower warm (showing the IAC is working)?

quote Originally posted by phonedawgz: Check to see that the ECM is seeing the VSS vial the ALDL cable

How do I do that without an ALDL to computer cable? It's on it's way.

quote Does the engine idle faster cold and slower warm (showing the IAC is working)?

Yes, yes
The speedo works and appears to be accurate.

[This message has been edited by n7vrz (edited 07-26-2012).]

Ok, here it is. Finally got the ALDL cable and TunerPro RT talking to each other and connecting to the ECM. Did my run and sent the logged file to Ryan.
The reason my car wants to die is the IAC counts don't go below 59. That should be down around 10. Lower counts means higher idle and higher counts mean lower idle.
So when I push in the clutch the IAC isn't catching the rpms at the right spot and the engine keeps slowing till it dies.
The IAC was working. Just not working correctly. I'm going to get a new IAC.

[This message has been edited by n7vrz (edited 08-02-2012).]

I was having this trouble a while back, exactly as you describe, on my 3800na. I took the IAC off and it was pretty dirty, so I sprayed it good with carb cleaner. I found a couple of dark spots on the pintle that looked a bit more than just dirt. I polished the pintle clean with a little steel wool, and the problem has been history ever since. My idle never drops below 900 rpm, and does so smoothly.

Getting back to this after other projects needed work. (The house.)
So, I replaced the IAC and took it out for a spin. This may have been it. Got up to temp and speed, pushed the clutch in and it didn't die. Hunted a little but did not die.
Tried that multiple times and got more of the same. No die but a bit of idle hunt.
I'm provisionally claiming success of 'Stop The Dieing Fiero Project'.
Now on to the 'Why Doesn't The Tach Work Project'.
Then I'll see about the 'Where Are All The Sensors Project' since no one seems able to provide a picture/drawing of where they should be. (My Haynes manual shows all the engines for the Lumina this engine came out of EXCEPT the 3.4DOHC engine.)

[This message has been edited by n7vrz (edited 11-23-2012).]

I may have been premature on the stalling issue. Took the car to the store 5 miles away yesterday and it ran fine to the store.
But on the way back it stalled every time I pushed in the clutch.
I would love to figure this one out.
I'll run another TunerPro RT log for Ryan at Sinister to look over. Hopefully he will have a suggestion.
If anyone else wants to look over the log file that I will make, let me know what file format you want it in, an email address to send it to and I'll try to get it sent.
I REALLY could use some help of this.

[This message has been edited by n7vrz (edited 11-26-2012).]

Is there a wire on D22 of the ECM - Manual Transmission clutch switch?

The 91 - 93 DOHC had a clutch switch that ran to the ECM. I can't tell you if the wire should have power with the clutch at rest or with it depressed however.

[This message has been edited by phonedawgz (edited 11-26-2012).]

It's been rather cold here recently and I don't have a heated garage.
Today I finally got around to pulling the D plug off the ECM. Found D22 and stuck a VOM probe in it. Turned ignition on, pushed the clutch and nothing. Yes, I touched the other probe to ground. I tried a couple of different screws just to make sure.
I know the switch itself is wired and working 'cause I can't start the car without the clutch disengaged.
D22 does have a wire in it. So now I get to unwrap the wires to see where it goes. Most likely thru one of the bulkhead connectors into the engine bay. Then try to trace the wire in the engine bay to see where it goes. If there even is a wire in the engine bay.
This may just turn into a 'wait till I start the swap' thing. As it will be so much easier to trace this stuff with the cradle dropped.
And the swap will have to wait till I can get the ladies to sort thru all their 'valuables' in the garage and get rid of them. I'm not gonna try a swap on my tilted driveway out in the elements.

Getting around to this again.
I added two ground straps to the engine. One goes from an intake manifold bolt to the right strut tower. The other from a throttle body bolt to the left strut tower. The IAC had been replaced a while back.
Today I installed a clutch switch and wired it to D22. The ECM see a ground when to clutch is engaged and opens when the clutch pedal is depressed.
The car has sat for about a month and a half since the previous work I'd done anything to it.
Started the car and there was a misfiring cylinder. I figured that is was just due to sitting so long. I took it out for a drive and the misfiring cylinder would cut in and out at random intervals. After about 10 miles it finally settled down. (Or so I thought.)
The wanting do die when the clutch is depressed continues.
On the way back home I gave the go pedal a good push like I wanted to pass someone and the misfire came back and it had a small backfire twice.
I'm wondering if my placement of the ground straps needs to be changed.
I did have TunerProRT logging and sent a copy off the Sinister. Anyone else want to look it over for a look see?

[This message has been edited by n7vrz (edited 01-20-2013).]

Got the clutch switch installed and it still wants to die when coming to a stop.
Sent a log file from TunerPro RT to Sinister and he tells me that the engine is running rich. That is until I push in the clutch, then when the rpm drops it goes very lean and that's when it wants to die.
So more tuning is being done.
Updates will be posted as they are available.

I do know that this is a common issue with this computer and manual swaps, since it was neven offered in manual from the factory. I know Ryan has done some tuning of the IAC tables to counter this behaviour, I havnt driven my swap enough to verify his work on it. I have been in a car that would stalll if the throttle wasnt blipped with the clutch engaged 94 DOHC w/ 94 ECU. I have a 96 DOHC with a 95 ECU.

IDK if it's helpful,
I made these pictures for someone a couple of years ago:
http://s23.photobucket.com/...FieroWannaBe/wiring/

[This message has been edited by FieroWannaBe (edited 01-30-2013).]

Thanks but I don't think those wiring pics are going to help much. The engine and ECM are '93. The intake is a '97 and the throttle body is a N*.

I see, for some reason I though I read '94 ECU.