Runs worse as it learns....

[Fast355]

well you did kinda patch it up by dropping 8 degrees at the distributor. perhaps in that case dropping 8 degrees across the map, putting it back to normal at the distributor, then slowly bringing it back up would be a good starting point...

but without a knock sensor, kinda hard to do any decent knock logging; so perhaps you should consider installing one?

If he is running the 7747 without a knock sensor and has not turned off the forced knock test there is a good chance its the test itself not the spark map causing the knock.

[billygraves]

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[steveo]

definitely good info, especially about the plug wires and shielding the pickup wires. i've gone through the exact same shit another car before, and now you reminded me to check mine out.

but yeah it does sound like it needs a retune

AFTER you resolve all other possible issues.

[EagleMark]

If he is running the 7747 without a knock sensor and has not turned off the forced knock test there is a good chance its the test itself not the spark map causing the knock.

If he is running with no knock sensor and it is not turned off properly in 1227747 then the knock count just keep counting and pulling knock retard timing.

The forced Knock test is run during PE, WOT... just when you need forced knock right? D'oh!

If you have some high pixel size pictures of under hood EFI install I can usually spot any issues like high voltage RFI noise interfering!

It's time for you to get a ALDL cable and TunerPro RT to do some data logging! We'll find the issue.

AFI used to have great customer service... when I worked there!

[billygraves]

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[EagleMark]

I'm going to take the truck over to a local place in Vancouver (WA) called Wong's Performance Tuning. I'm told they are very well versed in GM tuning. I hope I can afford what they have to offer.
I like to do things myself, but I only have so much time to figure it all out.

PM Dave W on this forum, he hangs out in that area Vancouver WA. and is super helpful in getting tunes straightened out. I am sure you will be pleased with his efforts. He can be found at http://www.gearhead-efi.com/Fuel-Inj...Old-School-EFi

Even if Dave W from Old School does not have time I'm sure he will help you get TunerPro RT setup and working on your Laptop! Then we have something to look at and see what's going wrong.

It sounds like your fuel maps are pretty good if it runs well after a ECM reset. Sometimes these old engines don't like to run at Stoich which is what the O2 sensor and BLM learn is what they do. The way to tune an engine that needs to run Open Loop is with a Wide Band and take the O2 sensor out!

This still leaves your timing issue! As you've been recommended get a GM ICM, it is an important part and aftermarket ICM have been proven to be in-accurate with timing. There could still be other installation/conversion issues. If you were closer to Coeur d'Alene Idaho I fix these conversions all the time.

You say the injectors flow at 180? 180 what? These TBI injectors are usually pound per hr. If you look on the top there are some numbers, write them down and let us know what they are and we can tell what size. Running at 26 PSI is very high pressure...

Wish you the best! Good Luck!