7747 problems

[01z28auto]

Hi guys, I’m working on a 1990 tbi 350 truck with a 7747 $42 ecm, Tunerpro RT v5 and a moates autoprom. The problem I’m having is randomly when I try to start the truck, all the data shown in TP datalogger is at maximum values and the truck floods and won’t run. I’ve tried to mess with cable connection, connection procedure and everything in between. Is there something in the ecm could be giving bad data or could it be the autoprom? Sometimes the truck fires up and runs great and has proper data,but occasionally this issue comes up. Thanks for any help.

[01z28auto]

I tried this again with a new pcm and new ribbon cable for the emulator but still having the same issue. Anyone seen this problem before? I can post a screenshot of the log dash when it’s having the problem if it’d be any help.

[stew86MCSS396]

What happens when you try to data log not using emulation? Only time I've seen what you're describing is allegedly the owner was running a "bad" MSD. Starts fine cold but as it reaches normal operating temperature, BLMs would move to 108. Flashed 15% fuel out of the idle VE area and it would react accordingly then climb back to 108. Flashed another 15% out and it would repeat this same routine to the point the engine would stall from flooding. After bypassing the MSD box, every thing went back to normal. We didn't investigate any further to determine if it was routing wires too close to other wires causing interference.

How are you connecting to the ECM? Dave W modified zif? Make sure when you Key On Engine Off, you get a solid cel before you attempt to start the engine. Once engine is started, cel should be off with absolutely no blinking.

[01z28auto]

I have a g2 adapter soldered in the pcm. I’ve had the same issue even after flashing a chip and not using the emulator.

[01z28auto]

It does have the rapid blinking cel when the issue happens but it’ll randomly work without changing anything.

[stew86MCSS396]

Meant to link G2 above post but messed up html and edited too much out...

Rapid flashing cel normally indicates a failed connection at the PROM.

One time while using a ZIF socket, had issues with the locking lever interfering with the ribbon cable. Took a dremel to the ribbon cable plastic housing to clearance the lever. Couldn't get it to connect at all. Rapid cel kept coming up but it was fine with a PROM chip. Took some compressed air to the modified ribbon cable and voila started working again.

Checksum disabled? This won't affect it on initial connection but after you flash your 1st bin edit to the emulator it goes wonky.

This has nothing to do with emulation but when you tried burning a chip, did you use the correct offsets?

Maybe at this point...visit the ^^^Dave W link above and make sure the same 5 pins on the G2 adapter has continuity, too.