I can only get diacom to work in diagnostic mode with my 87 TPI. It will not hook up in ALDL mode. Am I doing something wrong, or is this the plague of the older ECM's?

SInce I am only in dianostic mode, I can't drive around and get accurate readings on things. The idle is kept at 1000 rpm, and I doubt the timing is working as normal.

... and the 160 baud rate on the ECM is slow. Wow, it's hard to get any data captured that you can relate to time.

I hope I am missing something simple, but I fear this is the way it is.

Anyone?

MArk.

 

Are you running on top of DOS or windows? I have no experience with Diacom, however, windows comm driver may interfere or limit the com port settings. From what I remember Diacom is a native DOS app. If you are running windows9x restart in MSDOS mode. You can do this by pressing F8 when you see the starting windows message. Then select command prompt only.

William

 

I'm not using Diacom, but my homemade stuff has trouble hooking up in normal mode, too. Slap a 10kohm in there and it gets it OK. Take the 10k out (back to normal mode) and it stays hooked.

Don't know how the Diacom interfaces, but if you can hook in diag and then go to norm & maintain, it's worth looking into. Since this is something I'm not 100% thrilled with, I'd love to hear what you find out.

Come to think of it, I never used to have this problem running in stripped DOS 6.22, just since going to Win95, even if it is in 'GUI=NO' mode (Win95 version of DOS). Maybe I'll try running it off a DOS6.22 boot floppy! If that's the answer, then - COOL! Probably just coincidence though with my luck.

-Craig

 

I'm having the same problem with a 87GTA using an OTC scanner

 

Mark i read my OTC scanner manual ...and low and behold i found the answer ...on 87 pontiacs you need to choose road test mode other wise the computer automaticly goes into diagnostic mode...this was used at the factory to check the ESC module and idle speeds on the line.Diagnostic mode sets the idle at 1000 and the timming to 30 deegrees.To go into normal mode with my OTC scanner on a 87 pontiac i need to reprogram the scanner into different mode ..i hope this helps you