7427 Ecm Prom issues

I’ve got a 1995 k1500 with 7427 ecm. I am using a Moates g1 adapter with a 27sf512 eeprom.
I pulled out of my shop last night, and the truck hiccuped, I pulled into my driveway and it died. It would not restart.
I noticed the SES was flickering, so I pulled the chip and swapped a backup 27sf512 in, all was good.

I reburned both chips, and tried them both, and had no issues.
This morning I started it up, and I didn’t have the Prom verify ses flash, and the truck wouldn’t start.
I swapped another Spare 27sf512 and the truck started and ran fine. I drove 2/3 miles down the road and the SES lights flickered, and then went on; the truck went into limp mode, I limped it home and parked it.

The only thing I have changed on the truck; I’ve put led lights in the dash, and swapped back to the original alternator. Alternator charges just fine and no other issues.

thanks- Aaron

gearhead-efi link for information using the 27SF512 chip: http://www.gearhead-efi.com/Fuel-Inj...er-form-Moates

Make sure the Memcal is correctly installed with the G1 adapter.

dave w

Hmm...I ran burned 27f512s with a G1 in my truck for 8 years without a single issue like that. Coincidentally I also put LED bulbs in my cluster and a couple different alternators. I also had a battery ground cable go bad that caused a ton of starting issues before I found it...but never anything with the tune.

I'd go back over every piece closely. Could be something like a frayed wire in the harness that gets repositioned in the process of replacing the chip. I never screwed my ECM back in during those 8 years, if you haven't either, maybe a wire has rubbed or fractured?