Over the past few months I have been converting my Monte Carlo SS to fuel injection. Using a stealthram intake with a 730 ECM and a harness I purchased from e-Bay. This weekend was the first time I was able to test out my install. For the calibration I de-soldered the prom that was on the memcal and soldered a ZIF socket in it's place. I then loaded the super ajup v2 bin into tunercat and changed the cylinder volume and injector constant. I saved that and burned it to a prom and verified the eprom (checked out good). I then inserted it into the ECM and turned the key to the "ON" position. The fuel pump primed for 2 seconds but the coolant fans kicked on also and I got a solid SES light. I turned the car off and grounded the two upper right terminals on the aldl connector and when I turned the key I got the same results. Fuel pump primed and cooling fans with a solid SES light. I checked over my fuses and everything for the harness looks good. I then checked for continuity between the ZIF socket and the pin receptacles on the bottom of the memcal and all 28 checked out fine. How can I tell if the ECM or the memcal/prom is the problem? I am confident in my wiring and the harness I bought was from a reputable vendor. I did have a 91Z28 for a while so I am familiar with speed density TPI and I use to mess with the prom calibration a little as well. I need to have this car running soon. Any help is appreciated.

 

84KYSS
Check checksum of your EEPROM. The Eprom burner has an option how it calculates check sum. To disable check sum check by ECM set prom ID (Mask ID) to $AA. MaskID $AA is the GM engineering overide for the checksum routine.
//RF

 

Solid SES indicates that the CPU isnt even processing. A checksum will show up as a blinking SES as the ECM resets over and over again due to a bad checksum. Check the offset in the chip if applicable to make sure its correct and also double check all connections at the memcal. The only things needed for the CPU to process are all the switched and unswitched +12V leads and grounds. Omitting one of the +12V feeds can, I think, also cause a solid SES with everything on.

 

remove the prom from the memcal and check to see if the car will start up in limp home mode. Note if the SES light performs like normal or if it stays lit up solid.

I just read another thread a halfway down the page about the SES light.

Does yours at least blink on and off once before staying on or does it just go solid.

 

The light stays completely solid no blinking. It is like the ECM is not working at all but I don't understand why the fuel pump primes or the fans come on. I will check out the checksum. I have nothing to lose. Everything on the harness was labeled and I know where I connected everything. I know I have good grounds and the ignition feed is good too. I have 12+ volts on the two main power connection on this harness. I really didn't want to try to start the car until I know the fuel injection is working as it should. Can I try hooking up a laptop to the diagnostic port with the key to the on position?

 

The fuel pump and fans are built into the hardware in the event the main CPU system fails.

The chip goes into the MEMCAL with the notch facing outward. If you have another MEMCAL try it and see if you get the SES blink. If so that narrows it to the modified MEMCAL and/or the PROM burning. If the original PROM is OK try it i the MEMCAL and check the SES blink.

RBob.

 

I soldered the ZIF socket with the notch facing outwards. Also that is the way I insert the eprom. Unfortunately I don't have any spare memcals. I e-mailed the party that I purchased the harness/ecm from and they said that it sounds like a bad ECM and they will send a replacement. If the memcal was bad wouldn't I get some kind of code or erratic SES light? Hopefully a replacement ECM is the fix.

Chris

 

Carefully check and triple check your soldering job on the memcal :-)

Ask me how I know, been there done that.

Would also have to assume quite a few others have been down that road too.

It doesnt take much for them to get flaky

later
Jeremy

 

That was one of the first things I checked. Using my DVM I checked for continuity by inserting a small wire where the ECM pin would go and then probing the ZIF socket to make sure that it was soldered correctly. I'll agree that it is extremely hard to see if you have a good solder job on each pin with the ZIF socket.

 

Being a solder tech in the Navy I know that sometimes these ECU's are double layered circuit boards (at least my 870 ECU is). You have to make sure you have good solder flow through to the upper runs... ask me how I know that one. I chased a gripe around for a day before I got down to reading runs to pins top and bottom. Make sure you use flux too... that saves time. I saved my ECU by dipping each pin on my adaptor in flux and then applying to to the eyelets on the top and bottom of each hole so the solder would flow through and stick to both eyelets.

 

Wow I'm glad I found this thread! My SES light stays on with the car off and the ignition on as well. Plus I can't datalog for some reason, I don't want to hijack the thread but if anyone thinks they may be able to help heres the full story. I really appreciate anything anyone can do to help out!
https://www.thirdgen.org/forums/diy-...ml#post3359750