[camaro-69ss]

Fisnished up my install tonight, and I've got some weird things going on. First, I'm having a real hard time getting it to idle smoothly. It fluctuates all over.... very rich, then very lean, back and forth. But here's the real kicker - I can no longer shut my engine off with the key!!! AND it runs WAY better with the key in the off position!!! When wiring up the Holley harness, I took the power right from the battery and the switched source from the same lead i was switching my MSD 6AL with. It's hot when the key is on and cranking, off when the key is off. But after it's started the only way I can shut it down is by pulling the main wiring plug out of the ECU. I shut it down and retested the switched source and it goes on and off with the key. WHAT THE???? Any ideas on that one? So anyway, I start it and it runs crappy, then I turn the key off and it smooths out the idle and leans it down. Turn the key on and it runs rough and gets really rich. Or maybe I have those terms backwards..... with the key on when it runs terrible, the A/F ratio is 10. When i turn the key off and it smooths out the A/F ratio goes to 18.

I know I have a long way to go with the tuning, but I first have to figure out this key thing - there is something very obvious happening with the key on that the system doesn't like!

[JimM]

The "key thing" is common with the msd 6. They tend to backfeed the "turn-on" wire, everything on the ignition circuit stays hot.

Msd has a diode kit to fix it.

Then time to start tuning. First step is to check for fuel pressure in the return line, you did that, right? Must be near zero. Then set the fuel pressure, then start typing. 10 @ idle is rich, what basemap are you using?

[camaro-69ss]

Hmm.. never had a problem with the MSD before. Do you think if I remove the C950 switch feed from that source and find another I might fix the issue? I started with the TBI7503 map. Although I found some pretty strange values in some of the fields. I just stepped through the manual page by page and changed a few things that didn't look right. I checked the return line fuel pressure, there was none at all. On the feed side it's at 21-22.

[camaro-69ss]

But I still wonder why it runs so much better with the key off. It must be shutting off something in the system...

[whytry]

Do you have a kink in the line somewhere causing the pressure to build up then release?

[CarlC]

What is your timing measured with a timing light vs. the computer indicated timing?

[camaro-69ss]

I'm not using the ECU controlled timing. I don't have a distributor that works with it

I've got the key thing fixed and it's running pretty good. Now it's time to work out all the bugs with the fine tuning i guess.

[ProdigyCustoms]

Sounds like the iac is going crazy is why it is surging. The key off thing, is weird!