Anybody have access to a 7427 7,4 memcal?

[sturgillbd]

I picked up another 7427 pcm the other day. Memcal is BMHK. I was wondering if anyone else has a 7.4 memcal lying around that could post the number on their knock filter in their memcal for a 7.4. This one has the part # 1344292 which is the same as a 5.7 tbi memcal. Guy said the PCM was for parts or repair and I bought it for 28 bucks shipped. I read the EPROM in the memcal and did a bin compare on it to the BMHK bin from here: http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=756&d=1323149167 and it has 16k of differences. All of the differences are at undefined addresses. No big deal either way but it would be nice to have a 7.4 memcal because I have the later model BBC intake that doesn't use an adapter for the tbi, the harness out of the truck and the tbi. If this has the proper knock filter etc, the EPROM will be replaced with a flash chip anyway. Either the EPROM on this one is corrupt or it is a 5.7 that someone has tried to UV erase and write the BMHK bin to and it failed. It has a factory cover on the memcal but you never know what you are going to get from E-bay. I did test the PCM on my jeep using the jeep's memcal and it ran fine. Attached is the bin file and a pic of memcal with knock filter number. I may look through the hack and see what some of the differences are. Most of the differences are the bin from the $0E thread has 00 in dead space and when I read chips with the Burn2 the dead space is FF. Some of the differences seem to have actual code in them and my read shows dead space.

Thanks in advance to anyone who will take a few mins to look at their memcal.

Brian

[fastacton]

BPRK is 1345194

[sturgillbd]

Thank you!

[1project2many]

Mind posting the .bin file?

[sturgillbd]

It is posted along with the pic. Just below the pic. Update. Compared bin to Hack and all of the differences are in undefined areas. I put the memcal in my pcm and fired up the jeep. Pig rich but it runs. One error code is set. Error 32. I don't have an EGR valve so that would explain the error 32. I will test the PCM further when I finish tuning the jeep build but so far all of the parts seem to work. Maybe got a good deal on this stuff. The above posted bin may not be corrupt.

[JeepsAndGuns]

I used BMHK for a long time on my jeep cause it was for a 454 and a manual trans. I had so many issues trying to tune that bin, and I fought forever with it untill I finally ditched it for a 5.7 auto bin and never looked back. I dont think I could ever recommend that bin as a starting point for anyone to tune from. Seems like I remember someone else on here using that bin and having issues.
But on a slightly off topic question. Do you know exactly what vehicle that pcm/memcal was pulled from? We never could figure out what it was originally meant for. I even called a chevy dealer and had them look it up. All they could tell me was it was for a 454 manual trans, but not what vehicle. Best guess is maybe a med duty truck?

[sturgillbd]

I bought it and the PCM from ebay for $28 shipped. It was listed as not working / for parts or repair. Listing stated it was for a 1995 Silverado/Sierra 7.4 and NV4500. I received the PCM and took it apart and cleaned the board with soap and water to remove dust etc from it. Put it in my Panavise and went over it with a light and magnifying glass. I reflowed some solder joints that may have been questionable and re-assembled. PCM was fine when tested. I may run into issues if I actually use it but who knows.. I tested the memcal about an hour ago and it did start and run. Only error code was code 32 which is where I am not running egr on my build. I will message the ebay seller and ask him if he knows exactly what this combo came out of. I'll post the info if I hear anything back from him.

[sturgillbd]

I just went back and re-read the original listing on Ebay. He stated it came out of a 1995 Silverado 2500 2WD. He said the truck wouldn't run and they replaced the PCM and memcal and it ran fine. Put this one on e-bay and listed as not working.

[1project2many]

BMHK is definitely a C/K series, 3/4 ton or single wheel 1 ton. It's a replacement / updated prom for a '94 and 95 model released in '95. Part number 16209474 and crosses to 16220287. GM parts info says this:

This product fits 66 vehicle variants.
Chevrolet: 8 models, 30 variants between 1995 and 1996.
GMC: 7 models, 36 variants between 1995 and 1996.

Bithoist correctly identified this file and did not indicate a checksum mismatch, so it's probably not corrupt.