It's been a long time but finally I am able to do some work on my 57 4drht that has an LT1/AutoTrans for motovation. Last thing I remember in 2020 was a spark as I was removing the Alternator to Batt. wire, I think. At the time my scan tool read Ignition as the problem, but I didn't get to take the scan any further. Something like this may have happened before due to leaving the batt. hooked up while a friend did some welding on the car for me, so I figured maybe that was the case again. That's as far as i got unfortunately. Then the car sat on jackstands until just recently.

Yesterday I finished putting the "odds and ends stuff" back together.
(Thankfully! I recently found a Mechanic who stopped by and helped do all the other things i had taken off to upgrade but never got to do.)
When I went to run the scan tool all it would show was the message, "Vehicle is not responding."
I checked everything I could thing of on the scan tool and all I found was some corrosion in the scan tool's battery compartment which I cleaned up, checked connections and put the key in the ignition, spun the engine over until the oil pressure light went off, sans the fuel pump fuse. reconnected that but no start.

But I can not scan the system. I did take the old ignition module off but put it back on until I could verify it was bad. I have another one (GM) but am reluctant to install it before I can get an idea if there is another problem. Should I quite the dramatics, plug in the new $150 dollar part and hope for the best?

How can I check the old Ignition module? Thanks!

 

Not sure how to check the old ignition module, but if you are plugged in to your OBD1 port 12 pin connector -KOEO, and the vehicle is not responding, then it is possible that your PCM/ECM is fried. Each of these scanners work a little differently. My CP9690 specifically states that in addition to the cable to the OBD1 port, the scanner must be powered by the DC 12 adapter through the cigarette lighter. I have not tried with batteries and no cig lighter power connection. I think I may have seen your post on another blog about this, and someone mentioned OBD 1.5. From what I understand, OBD 1.5 was a term kicked around by some of the guys at GM referring to the phase-in of some PCM code/logic additions to the hardcoded programming on the chipset of the PCM, after 94 and prior to /up to 96. This only occurred on a few of the corvette's as they were rolling out and testing modifications for the new OBD2 systems. This OBD 1.5 stuff had nothing to do with actual connection at the port for the diagnostic scanners. So if your scanner can read OBD1 and actually cable connects to your 12 or 16 pin port, your scanner should be able to connect to the PCM if it is operational and coded to work with the LT1 engine PCM that you have installed. It is possible that your scanner is not compatible with the PCM I guess, but you said you had scanned it at one time and were able to connect. Hope this helps some. I can be verbose at times. Please correct me if the above is incorrect.
PS - I had "vehicle not responding" a couple of times with my scanner, and I just turned the scanner off and on and it worked. I think I jiggled the connect at the port too maybe. The comm ports on these are "Old tech" and they do take some time, like the old 300 baud modems (at least they don't squeal when they do it).
Dylan

 

I have seen the the plug-in you must make and I may even have the plug in a seperate plastic package that came with my Auto x Ray scan tool. It will also scan Chrysler and Ford OBD1 computers.
I doubt the Chevy Dealer in Lubbock TX where I bought it will know more than what you so kindly explained and Street & Performance whom I got the wiring and computer and who actually programed it is gone.
Mark the owner was a techinal master.RIP And a hell of s nice guy!
The scanner has a large plug that connects to the port wiring plug but in reality it gets all its information through 3 pins. The engine comp came with the engine from a Camero.

There are 4 fuses - from the port. 2for the computer, 1 for?? and 1 for the fuel pump. I can't make out what the one plug is for w/o the original printout which is somewhere nearby I'm sure. Any way..I've had the scan tool hooked up before many times and it worked great, it can even save content. By the way, I appreciate your attention to detail.
Jiggling the connections was one of the suggestions sugested in the Troubleshooting section. I jiggled the plug to scan tool connection but not the one to the OBD port as it's a tight fit. I'm going to spray them all with CRC cleaner as leaving the Scan Tool connected to the Computer Port for a few years may not have helped anything. If my scan tool starts squealling....
I have two, no 3, Camaro Firebird Service Manuals that will help me learn how to check the suspect ignition module with in hopes of not having fried the computer, and will refer back sir.
Thank you for the help. I appreciate it.

 

No problem with the ICM would have anything to do with you being able to communicate with the PCM. If what you have is an old AutoXray and a 12 pin DLC, it only needs two pins to communicate with the PCM (ground and serial data)-no power other than its internal battery required.

If you have electric fans in a stock configuration that use the PCM for operation, jumpering the DLC to ground might at least tell you if the PCM is alive (the fans should come on when you do this).

 

Rob has a pretty good idea with that. The fans come on when I jumper A&B with a paper clip on my 94 z28. At the time I was trying to flash codes, and wouldn't you know it, mine only turned on the fans, so it might tell you it's alive if those do come on. Kind of curious as to why you chose the LT1 for that 57 Chevy? Beautiful car!

Dylan

 

Thanks for the idea although I don't get how grounding Serial Data would give the fans any ideas but I tried with no joy. Now I notice the check engine light doesn't even come on/go off anymore. An d why the spark then the scan showed Ignition but years later all it showed was the VINR. The fan and A/C grounds are not visible but all in one spot that I will need to look at just to be sure there's no corrosion.

 

Well, I'm glad all ya'll's fans come on; I'm jealous becauyse mine?...not even a whisper of rotation!
Rob knows exactly what my ALDL connection looks like, that's for sure!

Why the LT1? Call it Royce Next Stage Deluxe. Mostly because og the SFI. Bonus- 23mpg+ as long as I don't matt it. That, and it gave me something to do as I recovered from a back accident at work. It all took awhile and during the interm it all went LS. No matter actually, I liked what i had. Still do. Mostly.

 

All good reasons I guess. Anyway, if you are tech savvy with a multimeter, you might be able to find out more about your PCM. I'm kind of afraid to go near my PCM. My PCM is pre windows 98 after all. https://kaiweets.com/blogs/news/how-to-test-pcm-with-multimeter Not even sure if the link info will work on an old model, and I am sure there are differences in the board. On the upside, you can probably score a new PCM for a couple a bills.

My current LT1 issue - replace the air intake gasket myself, pay someone, or just keep adding oil. Option 3 maybe not the best, but I don't drive her much.

 

The fans come on because that is what they do. It was an easy indicator that you were communicating with the computer in OBD1 days when you went to flash codes (last time you could flash codes on an f-body was 1993). The fact that the check engine light does not come on is concerning. Things to check would be that the PCM has all its grounds and power and for diagnostic purposes that the DLC wiring is good to the PCM. This assumes the lamp is ok.

 

Thanks you for the Link I can at least look at it, you know. As for your ride, your car your money.
And Thankk you for your input, I appreciate it.