Need some tuning help, '94 Astro with an LT1

[astroracer]

I just picked this van up Friday. I am the 2nd owner. It has 42,378 miles on it and is so clean, inside and out, it still smells new! The LT1 was built by Callaway and installed when the van was brand new. The LT1 runs good but the 4L60E has problems. It runs and drives but the shift points are all screwed up and I think it should run better then it does. Does anyone know of a good tuner in the Flint area that could look at the ECM and do some diagnosing for me?



TIA.
Mark

[astroracer]

Did some digging after work today. Pulled out the ECM. It is an Accel Electronic Control Module.

I can find no data or info on the WWW for it. Of course it's 23 years old so that isn't surprising...
It also appears to have a matching wiring harness with call outs printed on the wire.

The back of the box has a serial number and Spark/Fuel Management on the sticker

The question I have is:
Does this box have Electronic Trans Control?
Probably not, no mention is made on the sticker of shift control. So what did they do with the 4L60E? Swap in a 700R4?
I am taking the van out to my buddies shop tomorrow so we will put it on the hoist and see what we have.
ANY insight on this early FI Controller would be appreciated!
Mark

[astroracer]

I am talking to the guy who built the Throttle Body System I put on the wagon. Hopefully we can figure out a fix for this. If there is a 700R4 in there I am hoping he can build me new GM based ECM using a Trans Am Chip. The trans will need adjusting but I can do that once we get the computer figured out. A lot of speculation, I know. I need to get into it more.
Mark

[avewhtboy]

If your tech savy you can download tunercat and and use that to check the rear axle ratio and tire size setting which, if incorrect, would cause some erratic shifting.

Also if the Speedometer signal is incorrect it will cause the same thing.

Good luck not many LT1 users around any more!

Oops just noticed your not running the factory computer. So I dont think tuner cat will work...

[astroracer]

Thanks, yea I was surprised to find the aftermarket ECM when I popped the cover off. I think it would have been so much easier to simply plug in a '94 TA ECM and burn a chip to work with the gearing and tire size... Don't know what direction this will take. If I find a 700R4 in place of the 4L60E that will negate going to a stock style ECM. I am going to start researching new technology for the engine ECM. There is most definitely better stuff out there now-a-days.

[astroracer]

Well, the van had a 700R4 swapped in when the LT1 was installed. Now I am looking for schematics for this Accel ECM. I would like to replace it with a 94-97 F-Body manual trans ECU and having the schematic would make a simple job of swapping the connectors. Anybody? Help?
Mark

[andrewb70]

http://lt1swap.com/wiringharness.htm

Andrew

[astroracer]

Thanks Andrew. I've been thru that site a couple of times. Excellent information.
I just need the Accel wiring diagrams to move forward on this. I can't see paying upwards of a thousand dollars for a new harness when the one in the van will work if I can add new connectors...
Mark

[avewhtboy]

It may be easier to just use that harness and wire it into a stock ECM. Wouldnt need the Accel diagram just wire it into
the stock ECM using the link Andrew sent. The wires dont know which ECM they are connected too.

[astroracer]

It may be easier to just use that harness and wire it into a stock ECM. Wouldnt need the Accel diagram just wire it into
the stock ECM using the link Andrew sent. The wires dont know which ECM they are connected too.

Well, no, they do care what pin-out they are plugged into. I need the Accel diagram to be able to compare the two different ECM's. I would hate to plug an Accel IAC sensor wire into the GM 12v power wire. I need to know where every wire terminates in the Accel ECM so I can get the GM ECM wired correctly.
Mark

[andrewb70]

Found a link to an old catalog:

http://www.zcarcreations.com/downloads/Accel_FI.pdf

Andrew

[andrewb70]

Well, no, they do care what pin-out they are plugged into. I need the Accel diagram to be able to compare the two different ECM's. I would hate to plug an Accel IAC sensor wire into the GM 12v power wire. I need to know where every wire terminates in the Accel ECM so I can get the GM ECM wired correctly.
Mark

Mark,

I know it would be a pain, but couldn't you trace each wire individually?

Andrew

[andrewb70]

Page 146 has DFI pin-outs...maybe some wires are similar to your unit?

http://www.project33.com/media/DFI_G...structions.pdf

Andrew

[andrewb70]

Interesting thread...looks like your hardware...I believe that is DFI V6...


http://forums.corral.net/forums/engi...l-gen-6-a.html

Looks like same pin-out...



In your picture...I see a red wire...P1-C5...O2 sensor...Yellow...P1-C16....Inj B....Seems to match.

Andrew

[astroracer]

Ok Andrew... Thank You Very Much! Lots to download and digest here! I think you have put me on the right track. I also found a link to Dan White Racing, here in Mi., and it looks like he may still be using these ECM's... I have an email out to him right now. This is doable, even if I can use the old computer and just get it tuned correctly.
Thanks again, over and above what you had to do and I appreciate it!
Mark

[andrewb70]

Ok Andrew... Thank You Very Much! Lots to download and digest here! I think you have put me on the right track. I also found a link to Dan White Racing, here in Mi., and it looks like he may still be using these ECM's... I have an email out to him right now. This is doable, even if I can use the old computer and just get it tuned correctly.
Thanks again, over and above what you had to do and I appreciate it!
Mark

Glad to help! I just used Google, but some of the more interesting links didn't appear until page 6-7 of my search. Keep us posted!

Andrew

[astroracer]

I was pointed at this site: https://www.diyautotune.com/support/...t-lt1-lt4-l99/
They seem to have their chit together and are responsive to questions. I am just about ready to order this kit.
https://www.diyautotune.com/product/...ler-package-1/
Along with their wideband O2 sensor kit I think I would be all set. The only problem I see is getting engine connectors to terminate their pigtail harness.
I am hearing mostly good things about the Mega Squirt stuff. Anyone have any insight?
I will be taking the van to a shop next week. Performance fuel injection Systems. They build the TBI kits that I put on my '56 wagon a couple of years ago. Kevin, the owner, wants to look the van over before I pull the trigger on the DYI stuff. He can probably get all of the engine connectors I need to wire in their pigtail so I hope that will be an easy road.
Thanks again!
Mark