Crackle pops during wot

[MCTeeJ]

Start data logging, turn on all cylinder misfire channels, watch AFR

[D-VO]

No answer huh? Same thing just happened to me after popping an intercooler pipe. Limped home at 2000 rpm put the pipe back on, but now it won't go passed 5800-6000 rpm without misfiring. So far only tried reseting ECU because I thought maybe the trims went all out of whack. NOPE! Time to log.

[DarkPira7e]

@D-VO

This is an issue with a coilpack, guaranteed. I had this come up randomly recently. I replaced the top coilpack on the passenger side (following the misfire code it threw) and the problem went away immediately.

[tomm.brz]

log and check for misfire and look at injection DI end to spark, the value in ms at the rpm you get the problem, but I also think it s coilpack(s)

[FRS Justin]

If it was a coil or fuel issue it should throw a misfire cel. This is not happening so I would look at the tune and make sure. If you have a old tune that's for FI try it and see if it changes

[DarkPira7e]

Originally Posted by FRS Justin

If it was a coil or fuel issue it should throw a misfire cel. This is not happening so I would look at the tune and make sure. If you have a old tune that's for FI try it and see if it changes

Just don't forget that the tuner could've disabled the CEL. Not that they should've but you never know.

[steve99]

Check it not an overboost fuel cut set up in tune, if map sensor goes bad it can trip early

[jflogerzi]

Car may not throw a cel but it could still misfire.... Check for dtcs. When I was dealing with a idle lean condition due to tune, I would not always pop a cel but it would log a dtc and car would drive wired till clear. What AFR are you seeing at WOT, but I would get your car checked by your tuner

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[D-VO]

@DarkPira7e I'm getting no misfire codes. Mine are all still enabled except for the rear O2 and MAP sensor SES because I'm using an OMNI 4 BAR MAP sensor.
@steve99 How can I test the MAP sensor? I'm logging the boost level with the MAP and it's still climbing as it did in previous logs. The only datalog line that I see changing is the timing; it drops by 1 - 2 degrees during the misfire and AFR's start going up to a maximum of 12.8. It almost feels like its hitting a rev limiter.

[D-VO]

Also, when the coolant temp is low (not sure the exact number) the misfire happens @4500rpm

[jflogerzi]

Originally Posted by D-VO

Also, when the coolant temp is low (not sure the exact number) the misfire happens @4500rpm

What's your oil temp at that time? It could be a built in safety feature put in by your tuner that under a certain oil temp the car is setup to pull timing and might simulate what you think is a misfire... ( After talking with my tuner I found out he does this) the reason is to protect the engine from seeing to much oil pressure which he has measured during the warmup process. They have seen as high as 100psi during this period which he said no Bueno. It also keeps cylinder temps down during this process.

Also are you logging misfires counts? He showed me a table where in the hire rpms it requires 20ish to long a cell and at low loads it's was near 90!!! Yikes

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[D-VO]

Wow! Well I'm the tuner and I never programmed such a thing. When I get home I have to look at the log again to see the oil temps. Good call!

[steve99]

Originally Posted by D-VO

@DarkPira7e I'm getting no misfire codes. Mine are all still enabled except for the rear O2 and MAP sensor SES because I'm using an OMNI 4 BAR MAP sensor.
@steve99 How can I test the MAP sensor? I'm logging the boost level with the MAP and it's still climbing as it did in previous logs. The only datalog line that I see changing is the timing; it drops by 1 - 2 degrees during the misfire and AFR's start going up to a maximum of 12.8. It almost feels like its hitting a rev limiter.

Maybe test it against another manifold pressure guage.


Also make sure it reads close to 14psi or 1 bar with engine off igniiton on

[D-VO]

Ok. Maybe I can put the stock one back on for testing since the problem does happen right around 8psi