I have been doing some readind about PE (power enrichment) mode. Basically I would like to pull a little timing and add some fuel at the higher RPM's. I see the spark adder for PE mode, but dont quite understand the PE enrichment vs RPM. The values in the tables are all negative, which to me would mean less fuel, but I hardly doubt it. So I do not know which way to change it more or less negative or even positive for more fuel.

Thanks,
Craig

You must have a problem in your xdf or ecu file (or whatever software you're using).

Which ecu are you using? I'm going to guess you're using 32B for the 165, since that's probably what came in your 86 vette.

With that car and ecu, you can disconnect your cold start injector, and run ARAP & $6E directly (may have to disable VATS, not sure about 86 vettes, and put the injector constants to match your injectors). I have made a thorough xdf for $6E. If you want it, PM me, and I'll email it to you.

ARAP is about as aggressive as it gets from the factory. Lots of spark advance and about 12.2:1 A/F at high RPM. Can lean it out a little, but spark is big enough as is, usually, as long as your base timing is set right.

Most engines will make most power with 12.5-12.8:1 Air Fuel ratio (using 14-18% in PE), but, if you're between 12.2 and 13, there's only a very little to gain by making it perfect. Timing can make or break power more easily. Get it within 2 degrees of MBT, and you'll be fine. 4 degrees too low, and you'll be missing a few percent. Too much, and you'll be riding the knock sensor (and it usually over-retards the timing).

I am using tunerpro and I downloaded the arap bin and 6E xdf file from moates.net. Is there anything else that could be wrong.

At 1200 RPMs enrichment is 11.72% and at 3600 RPM's it is at -7.82% and stays that way the remaining RPM curve.

So I take it this doesn't sound correct at all?

That xdf does have a problem. The 11.72 is actually 22.6%, and the -7.82% is about right. I sent you an email. Hope your email doesn't block the attachments. If so, PM me again, and I'll zip them. I sent it a minute ago.

My xdf shows PE vs RPM in A/F, and PE vs Temp as %. Sooo, you'll see 15.3 or something at high RPMs, but the PE vs Temp is 22.66%.

I prefer to make PE vs Temp small at warm engine, and make the PE vs RPM follow what the engine needs (plus any fudge for MAF maxxing out).

Thanks again, I appreciate the help. In my reading I think of PE like the accelerator pump in a carb, that gives that extra shot of fuel. Is this correct. If so what do the values correspond to percentage wise. Is it percent fuel over the norm.

PE is the power valve and secondary jets in the carb's. The accelerator pump is AE (acceleration enrichment) in EFI.

IIRC the PE AFR is based on both an RPM and a coolant table. They need to be taken together then applied to the stoich term for the PE commanded AFR.

RBob.