minigunz

since the swap was done the computer tries to step up the idle when i let out the clutch, so to make it behave and atleast driveable, ive unplugged the IAC. i guess it thinks the engine is dying. do i need to change the computer and the prom? or just prom? or is it a different issue alltogether?

Six_Shooter

iTrader: (2)

Did you change anything to do with the ECM when you did the swap?

minigunz

no, all electronics are stock auto.

Six_Shooter

iTrader: (2)

Then yes, you need to swap the PROM to a manual PROM. Depending on the actual ECM you have an ECM may be required, but not usually.

minigunz

its a '92 ecm... but i still have no idea... i can get a manual prom from autozone for about 60 bucks, but they need the code from the prom, (the manual trans prom code) where can i find this info?

Tuned Performance

iTrader: (92)

the bccs are listed here
http://www.3rdgenformula.com/92/promcodes.htm

minigunz

but i dont have a big block....?

Tuned Performance

iTrader: (92)

Broad Cast codes

minigunz

oh! sorry i red that wrong, my fault.

minigunz

so according to that chart in the link, i shouldnt need a new ECM right? just a new prom chip

Johnny Blaze

iTrader: (15)

Email Tuned performance, have him make you a prom. Don't buy one from Autozone.

minigunz

will it be cheaper than $60 bucks? im kindof on a budget....

Johnny Blaze

iTrader: (15)

^ His prices are listed in the post, or you could ask him. All his contact info is there as well.

minigunz

i pm'ed him, he seems to specialize in v8 stuff.. maybe he has a spare memcal laying around....

Tuned Performance

iTrader: (92)

Sending a reply to your pm

Six_Shooter

iTrader: (2)

Being a 1992, the ECM should be a '7730, and you will only need a new MEMCAL. The MEMCAL contains the PROM.

Maverick H1L

iTrader: (8)

Speaking from experience:

YOU DO NOT NEED TO DO ANYTHING WITH THE ECM. Period. End of story.

Except for maybe a few months out of 4 years (took forever to find the HNL PROM), I ran my manual trans swap on an auto PROM. Never had any issues with running except when certain sensors and even a couple ECMs died.

Yes, the idle speed will hold where it is and even run a bit higher because the engine has been unloaded for the moment. But that is no reason to go and unplug the IAC. It's fine. Plug the IAC back in and leave it alone. If it's running well, you have nothing to worry about. If it's running like crap, start checking things over and leave the ECM until last if all else fails.

minigunz

thats the thing, being that its an auto memcal, the engine thinks theres a load when i release the clutch so the idle jumps up to about 2000 rpms. and doesent come back down. so to avoid this, ive set and unplugged the iac so the engine will idle steadily.. somewhat... i think that unplugging the iac, it put the computer in limp home mode... the engine ran fine when the auto was installed, diddnt mess with anything else, i keep my car in tip top shape at all times, i even have a sort of pre-flight check lol.. engine oil, coolant, trans fluid, etc..

enswrob

idle relearn first?

minigunz

there is no idle relearn on the 92's all you do is set the throttle stop and the computer does the rest. the IAC resets every keystroke.

project89

iTrader: (1)

u do not set the throttle stop
90-92 cars are the cars that u have to do an idle relearn on , the 85-89 2.8 cars not so much

Tuned Performance

iTrader: (92)

The only things I can think or is idle relearn or the orange/blk p/n wire is grounded. Or its with the calibrator .

Copperhead

Is your speedo correct? Are you using an SGI-5 adapter? With my T5-T56 swap there's something flaky in the adapter or the wiring, and if it's not working the car wants to die. As soon as the SGI is working it smooths right out.

Tuned Performance

iTrader: (92)

A intermittent loss of vss 24 would do that.

minigunz

the car idled fine before i removed the auto trans, i could start it, it would run through its warmup cycle, then idle down according to engine temp. it did this when i first started it after the swap too, i let it warm up before i went for a test drive. it ran fine just like normal, when i went for a drive for the first time, i put it in gear, and went to let out the clutch. well, i guess the engine sensed it as a load, and adjusted idle accordingly- up to about 2000 rpms when i disengaged the clutch. ive never had to do an idle learn. i work at a shop with access to shop key, mitchells, and alldata- none point to an idle learn that i know of. is there something more i need to do with the park/neutral switch? also, bear in mind that im still runnimg the auto memcal.. personally, i think this may be the source of my problem.. how does the manual memcal regulate the idle valve??

Tuned Performance

iTrader: (92)

yes the idle speed is referenced off cts. The p/n is a adder but only 50 rpm.
The p/n switch is in cavity D16 snip it or unpin it.

Six_Shooter

iTrader: (2)

Yes, swap to a manual MEMCAL, and your problem should be resolved, provided there are no mechanical issues (pinched, cut wires, pinched hoses, etc), that happened during the swap. Things happen sometimes that we miss during a swap. It's happened to me, and will likely happen to me again.

About the idle re-learn thing. I've found ONE Car in all of my years of swaps and disconnecting batteries to perform electrical work that seemed to need an "idle re-learn" performed. If I were to do the math, that would be less than 1% of cars that were deemed to need an idle re-learn actually needed it.

Cadaver_Puncher

Tuned performance did my 3.1 prom.
He does awesome work and knows everything about ecms.
Forget autozone. They will get it screwed up 95% of the time.
Just pm hotmail your engine, transit and rear gear ratio. Also if you want smog crap deleted he can program that as well.
his prices are very good. Judy hit him up. He'll get it running better than ever.

minigunz

update! i think i fixed it maybe... just went for a short cruise earlier, but before i did, i plugged in the IAC, started the car, let it warm.... and then switched the p/n switch to drive (or some other forward gear..) and the idle stayed rock steady even under a load. im thinking i could use this as a theft deturrent... lol run wires to a toggle switch under dash, flip switch one way to start, the other way for drive? but anyways, i drove the car to go get pizza, and it ran flawlessly. one more question though....

i swapped 4th gen pedals into the car. long story short, in order to get the right geometry on the master, i had to drill a hole in the pedal and put another peg in just low and in front of the original one, in order to get more throw at the master cylinder....

have any of you experienced this problem?

Copperhead

Sorry to derail, how do I trace that?

Tuned Performance

iTrader: (92)

Is it getting a code 24 ? I would think poor connection in that circuit or a issue with the sgi-5. The sgi-5 I have read can be kinda glitchy but as far as I know there is no other manufacture alternative. it depends how your using it idk if a drac could be used as a calibrated despite the low ppm input.

jensen73110

iTrader: (4)

What kind of pizza?

Tuned Performance

iTrader: (92)

minigunz

Sams n.y. pizza. Great stuff

minigunz

update! the car runs loads better, every time i go to leave, i switch the p/n switch to drive, and the ecm seems to suppress all the irratic idle issues..... except- when it goes into closed loop. like after a drive, and i stop at a stop light. its like when the idle drops for closed loop the iac goes nuts, ive driven it on the interstate at 80 mph, the car runs excellent- overdrive is the bees knees.. but... that surging idle...

Six_Shooter

iTrader: (2)

Why don't you just get the proper MEMCAL?

OrangeBird

iTrader: (1)

This sounds like the logical solution . GM had a manual and an automatic tune as separate entities for a reason . If the same tune would have worked for both transmissions , don't ya think GM would have saved the money and went with a "one size fits all" tune ?

minigunz

thats what i figured too, just diddnt want to spend 60 bucks if i diddnt have too. is there anything i have to modify in order to get the manual memcal to work correctly?

Tuned Performance

iTrader: (92)

Plug and go play

minigunz

sweet.. thanks guys.