popping sound when engine is under load

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05-05-2012
USAFquez

popping sound when engine is under load

I just got my 383 SBC up and running again. I'm using Holley's EFI system with computer controlled timing. I think I may have my timing off a bit. I'm getting a loud pinging/popping sound from the engine whenever I try to give it gas when the RPM's are real low or when I gas it in a higher gear. I don't see anything out of the norm with my timing. I feel like I've had this problem before but I can't remember how I fixed it. Any advice?

SPARKhttps://static1.pt-content.com/image...05/spark-1.png

AFRhttps://static1.pt-content.com/image...2/05/AFR-1.png
05-10-2012
loser187

Hard to tell from the maps you provided without a lot more details. I have a 406 running the HP EFI setup myself. First thing I see is the fuel table looks a little lean and also the timing seems to be a little lazy. I have a 250 @ .050 cam with fast burn alum heads on my 406 and it likes about 25 degrees timing at idle and all in of 34 by 2700 rpm. Send me some specs and a data log if you have time and i will help if possible. Once those two maps are set then the fine adjustment of tip in, coolant modifiers and so forth can be adjusted...

Also i use the auto lean table/adjustment to help quickly adjust the map when i change the afr and such. I do not leave that on afterwards because it seems to keep refining when the thing should leave me alone :). If you want to send me ur data files i can look at them. PM me, Chris.
05-10-2012
USAFquez

Quote:

Originally Posted by loser187

Hard to tell from the maps you provided without a lot more details. I have a 406 running the HP EFI setup myself. First thing I see is the fuel table looks a little lean and also the timing seems to be a little lazy. I have a 250 @ .050 cam with fast burn alum heads on my 406 and it likes about 25 degrees timing at idle and all in of 34 by 2700 rpm. Send me some specs and a data log if you have time and i will help if possible. Once those two maps are set then the fine adjustment of tip in, coolant modifiers and so forth can be adjusted...

Also i use the auto lean table/adjustment to help quickly adjust the map when i change the afr and such. I do not leave that on afterwards because it seems to keep refining when the thing should leave me alone :). If you want to send me ur data files i can look at them. PM me, Chris.

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