Misfire data log

boost88

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Ok so I got new coil packs for testing. Car seemed better than on the oem coils. But still broke up kind of like originally now. Just a few sputters and it's back to full power.

So coil packs not it. Maybe plug wires I've heard the Ford racing 9mm ones can be junk. Also a note I hooked up a fuel pressure gauge to check and it holds perfect around the 45 psi mark where it should.

Question: since it's only wot it's most likely not o2 sensor related because they don't control fuel at wot correct?

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2003RedfireVert

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Ok so I got new coil packs for testing. Car seemed better than on the oem coils. But still broke up kind of like originally now. Just a few sputters and it's back to full power.

So coil packs not it. Maybe plug wires I've heard the Ford racing 9mm ones can be junk. Also a note I hooked up a fuel pressure gauge to check and it holds perfect around the 45 psi mark where it should.

Question: since it's only wot it's most likely not o2 sensor related because they don't control fuel at wot correct?

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WOT fueling does not use O2 data, correct.
 

boost88

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Data log show good battery voltage. I ordered a crank position sensor and cam position sensor with new o2s as well. The dip in rpm seems like it might be an issue so I'll throw 100 bucks in parts at it

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BigPoppa

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Just a wild guess here, but try cleaning the MAF. Costs one can of cleaner.

Also, there is no possible way there was 54k misfires on a single cylinder in that short amount of time. Your rpm would have to be way over 135000(est.) to see that much misfire for a split second. The computer isn't capable of those processing speeds that is most likely a signal glitch for the logger.

The breakup is real, but it may not be due to misfire if the computer is cutting fuel due to the MAF from being dirty and signaling a drop in injector duty time.
 
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boost88

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This is one thing I haven't done. But you're right it's a cheap check. I might even have some at home. One thing that deterred me from doing it was the maf counts in my data log looked correct. It was a nice steady upscale like it should have been

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boost88

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Just a wild guess here, but try cleaning the MAF. Costs one can of cleaner.

Also, there is no possible way there was 54k misfires on a single cylinder in that short amount of time. Your rpm would have to be 13500 and way more than that to see that much misfire for a split second. The computer isn't capable of those processing speeds that is most likely a signal glitch for the logger.

The breakup is real, but it may not be due to misfire if the computer is cutting fuel due to the MAF from being dirty and signaling a drop in injector duty time.
So you had me curious.... I took a look at my maf counts again on my data log and it looks normal. Only if you focus on the misfire itself but if you check before the misfire a few cells roughly .1 seconds prior you see this.

I double checked my other logs of known good runs. No more than a single cell dip in maf counts through out a full wot pull
misfire.jpeg


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