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slight knock at cruising speed

488 Views 7 Replies 5 Participants Last post by  KWIKR 1
In OD cruising at 65 I'll sometimes get into the gas slowly up to 80 mph and see some knock like 0.2 to 0.8 and not being in boost. Then It will go away. Should I just raise the FP a little?

87 GN Hardtop~Stock motor, Mease stock intercooler w/Duttweiler big neck,stock intake, stock tb and plenum, TE51 w/.63 housing, stock D5, MSD 50's, THDP, ATR 3" dual exhaust, big mouth cold air inducition, SMC alchy injection and egt gauge, MM boost command, PTE remote oiling system, Walboro 340 hotwired, 10 mm Magnecor wires, AC R43 plugs @.035 Adjustable regulator, ATR 3" maf pipe, B&M tranny cooler, Deep aluminum tranny pan, Dynotech shift kit, scanmaster 2.1, Testa alchy chip, dual airbags, vdo gauges, autometer boost gauge, front braces and rear seat brace, Bilstein shocks, more mods to come
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is the car kicking out of lockup or or OD? if so it may be transitional knock. If its staying in Lockup it could be just because of the load on the engine.
I usually get knock at highway speeds when the car downshifts.


1986 Buick Grand National
TA-49 Turbo, 009's, Hooker cat back, CAS V4, Art Carr 3000 stall, BGC 3'' Downpipe, ported elbow and all the other usual stuff.
Buick, Go fast with class
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yeah it was in OD at lockup the whole time.
is your egr working correctly?

well i tested the egr by pushing up on the diaphragm while engine was idling and then engine stumbled as I pushed up on it.
Does your scanmaster show spark advance? Maybe there's a hair too much timing. I don't think fuel pressure would help because the computer will correct for it.
There is a lot of load when the tcc is locked and in od.


Eric Marshall
'87 GN, 4.1 Stage 1, PT70-1, GN1's, ATR Single Shot, 52lb. injectors, TH350 tranny, FAST fuel management
'87 GN, Mostly Stock, Hooker exhaust
chip i'm running right now is a Testa chip at 21* for alchy injection
I'm getting the exact same thing with a JC VT chip set up for alchy . and I'm running a N/L .

[This message has been edited by KWIKR 1 (edited April 18, 2002).]
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