Datalog ignition timing not matching commanded timing (i.e. tables)

1120 Views 4 Replies 3 Participants Last post by Cougar5.O, Aug 13, 2021

Blown85GT

Discussion Starter · Jul 28, 2021

I posted this over on eectuning.org, but didn't get any responses, so I figured I'd try here.

I recently disabled the WOT vs rpm functions in BE and adjusted my sea level table (disabled altitude spark table) to accommodate. My peak timing should match what I had for the WOT spark vs rpm (or close to it).

What I see is that the timing in my data log does not match what I have entered in my sea level table. At WOT, it seems like all my actual values are about 2 degrees (or more) less than my sea level table at that same rpm and load.

One example, at WOT, 4000rpm, 90% load, I should be at 32 degrees per my sea level table, but the datalog is saying around 29.8 degrees.

EGR disabled.
Load%=Load

When I had the WOT vs rpm functions active, datalog timing match that spark function.

I looked through all the scalers, functions and tables to see if I could find why, but coming up empty.

Any thoughts for why my data log timing doesn't match my table?

BTW, I don't have my blower belt on, so this is currently NA

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Blown85GT

Discussion Starter · #2 · Aug 4, 2021

Well, no responses here, but I did get a couple over on eectuning.

It appears the ECU/Tune was pulling timing values from the Altitude timing table even though I had it disabled in the tune (per the Z_SPKINT scalar).
When I checked the log and compared to the Alt. table, the timing values seem to match.

I updated the altitude table to match my base and sea level tables. Base and sea level tables were identical before, so I just copied that over to the alt. table so now all 3 are identical.

Datalog from this morning indicates my commanded timing is now what I expect.

The question now is why was/is it pulling from the altitude table even though I have it disabled ?

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FFRCobra

· #3 · Aug 5, 2021

Maybe the creator of your definition mask didn’t map that scaler to the correct part of the binary file or that scaler isn’t doing anything at all. Ask the def maker.

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Blown85GT

Discussion Starter · #4 · Aug 5, 2021

Yeah, that sounds like what is happening.

I confirmed yesterday that updating the altitude table has corrected my timing mismatch.

So, for now, I'm just going to keep the altitude table active and any changes I make will get copied to all 3 tables.

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Cougar5.O

· #5 · Aug 13, 2021

Blown85GT said:
So, for now, I'm just going to keep the altitude table active and any changes I make will get copied to all 3 tables.

Might as well, has the same effect and it's 100% reliable.

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