Intake backfire with new chip....
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,309
Likes: 20
From: Woodstock Georgia
Intake backfire with new chip....
The car ran good yesterday during my leakdown cruise. I installed the new custom chip for the blower, and now I'm getting a backfire through the intake and have to run at least 10-12 degrees of initial advance just to get it going......I thought maybe the advance was too great, but I get the backfire when I drop it to 6 degrees....Any suggestions?
Burning Brakes
Joined: Apr 2004
Posts: 762
Likes: 2
From: Huntington ma
Sounds like the initial timing setting in the chip (constants table) isn't set right - it should match (or be close to) the physical baseline setting of the distributor in the motor (with no EST advance control). This is something that whoever burned the chip should have asked you for.... That constant setting in the chip baselines or zeroes the timing curve - it is the starting point for everything. Sounds to me like it might be set too high for what you have. I'm guessing.....
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
most engines will backfire if running lean....past experience with blower motors is they are also much more susceptible to induction firing, especially cyls 5-7 and 4-8...''sneezing'' the blower requires immediate attention if its a positive disp type, centrifugals are more tolerant.
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,309
Likes: 20
From: Woodstock Georgia
Greg emailed me this morning indicating that he believed it was a lean condition. The blower is centrifugal, and no backfiring occured over 500 rpm, and was intermitent. The fact that this is an early 86 block, with forged internals, has me breathing a little easier as well.
