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What is retarding my timing?

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Old 08-14-2004, 12:43 PM
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Unfortunately, all the scanners tell you is what your timing and KR are. None of them list what tables in the computer are contributing to the timing. EFILive may have some feature like this in a upcoming version that isn't out yet but, I don't know if it'll be that powerful or not.

Sorry I don't have a definate answer, Jim will chime in again I'm sure later. He has alot of experience tuning a whipple setup and can probably help figure it out. Having your own tuner(like edit, or hp tuners) would help as you could make changes quickly and test them out without shipping your PCM back and forth.
Old 08-14-2004, 12:47 PM
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i have seen the delta burst knock tables but have never messed with them before. i think it is a knock issue, maybe a knock learn issue, or even just a lack of programing for the high load low rpm timing tables. my stock 4.8 file shows as little as 4deg of timing at 1800rpm and .7gm/cyl. he is likely seeing that load value or higher at part throttle right before the down shift.
Old 08-14-2004, 12:55 PM
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Wow, .7gm/cyl is pretty high for such a low rpm. The timing values are low in that area.

He could also be getting timing pulled from the IAT vs. Load table. It starts pulling timing as low as 95 degrees on the IAT.
Old 08-14-2004, 01:00 PM
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yeah, your right, that is probably too high of a number for load but the timing does drop is the load goes up, then factor in the warmer IAT's, not sure what all programing is normaly done.

edit, i just looked up some turbo logs, i see over 50gm/cyl at 2000rpm just by loading it on the line. i only get about 2psi at that point. .70 might be close.
Old 08-14-2004, 01:03 PM
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It'd be nice to see a Edit file of his computer along with a EFILive log file. It'd be easier to help track down the problem.
Old 08-14-2004, 04:01 PM
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Ok, hope this helps.

Long term fuel trim -4
Long term fuel trim -6.25
IAT 89
Spark 0.3
Knock retard 0
Boost 5
Fuel pressure 60
rpm 2000

The spark was up around 40. I hit 55mph, felt the torque converter lockup, lightly pressed the gas, these were the results. I'm hoping a lightbulb will go off in someone's head. Fingers are crossed. I sent a link to this page to Allen also. Thanks guys.
Old 08-14-2004, 05:04 PM
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thats not so good, it would be nice to look at the programing to see where the timing is set.
Old 08-14-2004, 08:50 PM
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This is what I've mentally gathered when looking into Burst Knock:

Burst Knock pulls timing when the throttle is "tipped in", if the Burst Knock value is exceeded. From what I understand, it's there to simulate what an accelerator pump does in a carbureted engine, but just on the "engine side" of things.

Burst Knock isnt really a kind of knock, and it's not supposed to be logged as KR. It seems as though it should be called "Burst Anti-Knock".

Sooooo.... Personally, I think DHD is seeing Burst Knock.

EDIT: Sorry, just re-read and noticed that KR and advance can't be logged at the same time. I thought no KR was being recorded.

I think it could go either way. Either of the three ways, actually.
Old 08-14-2004, 08:57 PM
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with only adjusting my low and high octane tables and my IAT vs load table i have prety good control of my timing. same goes for my 99 with a whipple. without seeing his edit file it is kind of hard to eliminate posiable problems.
Old 08-15-2004, 07:14 AM
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Is there a way to disconnect the knock sensor or "burst" knock sensors? just long enough to see if that's the problem?


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