Hi All. I'm new to this site, but have been a long time member of LS1Tech.com. I've been working on cars for most of my youth and all of my adult life. I've built two LS1/6 speed swapped cars so far that also had full restorations. A 1976 Trans Am and my current car a 1968 Camaro. I'm actually in the process of selling off my factory ECUs and have the intentions of buying the latest Terminator X Kit for my Camaro.

Anyway, the issue that I'm hoping to get a little assistance with is getting my Dad's 1971 Chevelle running properly. So a little background on his setup, he is running a 496 BBC with aluminum heads, moderate sized roller cam, roller rockers, dual-plane Edelbrock intake and etc. When he first built the car he had a 850 DP and could never quite get the engine running right. The RPM would break up around 4K. Then I had a friend who was selling a complete Terminator EFI Throttle Body Kit and he jumped on it. After troubleshooting on a few things, eventually we got it running really well with the GM large cap HEI. Eventually I suggested that it would be better to run the GM small cap HEI to allow the computer to fully control the engine, and he agreed and bought the parts. One thing that I should mention is that for some reason when we set it up initially, the EFI didn't like it when the fuel pressure was at 43 psi, but as soon as it was at 55-58 psi it would run beautifully. We updated the tune to accommodate the added fuel pressure.

Now at the same time he swapped out to the small cap HEI, we swapped the dual-plane for a single-plane Edelbrock intake. We followed the instructions just the same as before, but this time, we got the car running good by ear at around 2K RPM, but when we put the timing light on to sync up the actual timing with the commanded timing, we were way off. The timing light was showing 45°-50° and the commanded was around 27°. The closer that we got the commanded to actual, the worse that it was running? Initially it ran pretty good, but the close we got to sync the timing it would idle higher, so at the same time we were trying to get the IAC to between 2-10%. The closer it would get to commanded idle, it would stumble & die.

I was puzzled so I asked my dad to confirm that the timing was accurate, so he pulled the front cover off and it is definitely lined up dot to dot. I recently made piston stop in order to confirm TDC, but in the meantime I'm wondering if there is something we missed? We bought the correct 558-304 harness that goes from the HEI to the Terminator Harness, and the coil is hooked up correctly. We followed the instructions again to a "T" and confirmed all sensors are working correctly and reading accurately. We followed the Wizard for setup and for TPS set each time we messed with the idle screw. Any help would be appreciated. Thank you, Ryan