Timing problems on carburated 86
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Joined: Oct 2002
Posts: 57
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From: Wichita Falls TX
Timing problems on carburated 86
I am running a small block 406. Have removed all TPI and am running a Holley doublepumper. I am still using the computer to control the timing. I was using this same setup when I had the less powerful 350 in the car and didn't notice many problems. With the 406, I am getting a misfire that I believe is due to the timing. Have checked the timing with the car under some load and under no load. Under no load it seems to act as I would expect (about 35 degrees at 3500 RPM), but under load, as soon as I bring the RPMs up the car jumps to over 45 degrees advance. I would like to keep the computer controlled timing for the safety of the knock sensor. I do not have any of the other sensors (MAF,TPS,O2,etc.) hooked up. If anyone can help shed some light on how I might fix this problem, it would be greatly appreciated.
Melting Slicks
Joined: Apr 2001
Posts: 2,122
Likes: 224
From: Ca.
Re: Timing problems on carburated 86 (ncccracer1986)
Being as the ecm uses the maf etc. to calculate load...and the timing tables are rpm vs load....I don't see how you're making it work???? Sounds like the ecm is assuming no load and then increasing the timing vs rpm only.....
Drifting
Joined: Mar 2001
Posts: 1,636
Likes: 3
From: Lafayette IN
Re: Timing problems on carburated 86 (drive it)
I agree with the previuosly mentioned comment.
A better bet would be to use a vacuum advance HEI usit out of a mid-70's Chevy. Of course you lose the knock sensor, but taking care of preignition is a lot easier with a carb. Well, I take that back...you take care of it the same ways, but you don't need a laptop to take care of it. Good luck, -Matt-
A better bet would be to use a vacuum advance HEI usit out of a mid-70's Chevy. Of course you lose the knock sensor, but taking care of preignition is a lot easier with a carb. Well, I take that back...you take care of it the same ways, but you don't need a laptop to take care of it. Good luck, -Matt-
