When having a negative spark advance while scanningwhat dose it means?
Provided that my VE table is fine and the low octane table pretty much stock (Running SD mode)?This happened in part throttle.
Is that a tuning or mechanical problem?
Any suggestions.
it means that timing is set to fire ATDC (after top dead cente). this is when the piston is traveling down the cylinder
Check that your not commanding negative timing is you hi/low spark tables, if not then look at your adder tables (IAT, AFR etc) these may be taking away your timing
Also check that your not getting knock when your getting negative timing cause knock will also pull timing
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Full Castle Hill Exhaust with 2 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and 3.73 diff gears
post a tune and scan.....................
Sulski Performance Tuning
2000 WS6 M6 - LS6 (long block, refreshed top end), 10.8:1 CR, 90 mm ported FAST, Exo-Skel, 227/232 cam, QTP HVMC, EWP, GMMG, 9" w/4.11s
2018 Sierra SLT 5.3L A8 - Airaid intake tube, GM Borla catback, L86 Intake/Ported TB
negative timing can be very normal on a cammed car at anything below 2500rpm and upper side of the cylinder air in the spark table
-Scott -
Thanx guys but I solve the problemmy stock timing table was from 0 to 10 in the area am having the negative timing in so I change it to 15 and above and WALLA the problem solved
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