Where is all this spark advance coming from at startup and in open loop. My spark curve has nothing close to what the scanner is telling me. In closed loop it runs from the spark table and after running in closed loop then jumps to open loop it continues to use the spark table. The problem is only during initial startup. What the hell is causing this. Pe spark advance is 0, egr spark 0, and egr is programmed out. Spark bias at 9.8, I even tried zeroing out this and still got the same during startup. Yesterday I tried starting my truck after removing a normal chip with a chip that locks the blm to 128 and the dam thing wouldn’t start. I then looked at the spark advance and seen it at 71deg. I then put the old chip back in and I still got the same thing. After screwing around and reseting all the ecm mal. Codes it started.

This is what I got during startup:
1100rpm 28.8kpa 45.4deg

this is what the spark table is showing for that rpm:
1100rpm 28.8kpa 25deg.

Where the hell is all this spark coming from initially. It does go away but for the first several minutes its way up there. I am lost with this man.

383 stroker, 64cc 23deg trickflow heads c/w edlebrock performer intake and adapter, cam is an extreme 4x4 comp. Cam. 12-235-2 grind ( .447/.462 lift, duration 210 218 lift @50, 111 lobe separation) . unit has hypr. Flattop floating pistons, eagle cast crank, 5.7eagle rods. 10.2:1 comp. Headers c/w 2.5” flowmaster exhaust. 16147060 pcm, $85def
454tbi 80lbinjectors

 

In the TPI bins, there are tables for start-up spark advance and for coolant temp compensation. The first one adds a few to several degrees to the base timing (computer isn't using the main spark advance table during start-up), although I've zero'd mine out to make it easier to start my >11:1 compression engine. The second table adds up to 10 degrees of timing when the coolant temperature is lower, and also subtracts some timing when it's hot (240 degrees and above).

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Greg Westphal
'87 IROC 355TPI/A4

 

my 85def. has no such table in tuner cat for startup spark, now what? did tunner cat forget to put this in? by the way my base timing is set at 0. it sure runs like crap when i first start a cold engine with 46-42deg! once this goes away it runs fine.

 

TUNERCAT came through again. sent email and they edited the def file which gave me the cold compensation spark, startup spark, and all the tranny mods for performance shifting and kickdowns. great guys to deal with.