[ANTHONYL79]

2016 Camaro SS A8 at about 5100 RMP at WOT gets a weird lean spike on Bank 2. Motor is fresh with forged piston and rods, cam 235/250 LSA 114 32% fuel lobe. Has LT4 HPFP, LT4 injectors, AEM aux pump on a 2psi Hobbs switch. Procharged makes about 12psi. Anyone have some instight on what to look at? Plugs are NGK 6510 gapped at .028. with MSD wires. Replaced plugs and didn't see anything out of the ordinary.

The car made 750 RWHP, there is a strange dip in the dyno curve at about 5100 RPM that correlates with the dip on the HPT log. The dip causes about 80HP drop.

Attached are the current tune, channels list and a test drive.

Thanks for any input.

[KingLT1]

I don't see a lean spike in your log. What I do see is you low side is a bit low and it's too rich. It's rich because your LTFT are positive and the ECM takes the last read positive number before entering PE and adds it to the PE fueling. Need to tune MAF down in the closed loop region so you have negative values this way no fuel is added when you go WOT. Also getting random KR which could be causing power to drop.

I would adjust MAF so LTFT are in the negative 3-5% range, raise low side pressure to 70, and fix KR.

Also, your wideband reads really erratic. Never seen one do that.

[cjperformance]

I found life much simpler after turning off LTFT. Had mine enabled for the longest time and it always messed with WOT. Saw a tune that had it disabled, and my life has been simpler since. STFT still running. Maybe not what you want on a daily??? But it works well for me.

[cjperformance]

I see the dip right at the 5:34:40 PM mark. RPMS come up then go back down slightly.

It's right before the KR starts kicking in and right before the timing starts coming back up, but not sure of the root cause.

[KingLT1]

Yeah you can turn them off. I prefer to leave it on...it's not hard to tune properly.

Is that the dip others have posted about and some mentioned it being oil pump related?

[ANTHONYL79]

Well decided to step back from the laptop and pulled out the Snapon Scanner. Found injector 6 was stuck wide open. Definitely runs and idels better, next to throw the laptop back on it and guve it a test run.

Injectors are only 7ish months old. Contacted supplier and they are going to replace it.

[KingLT1]

Be curious to see if that smooths out your wideband reading in the chart plotter.

[ANTHONYL79]

Originally Posted by KingLT1

Be curious to see if that smooths out your wideband reading in the chart plotter.

I will take a log tomorrow on the way to work and post it up.

[Kerry]

Originally Posted by KingLT1

I don't see a lean spike in your log. What I do see is you low side is a bit low and it's too rich. It's rich because your LTFT are positive and the ECM takes the last read positive number before entering PE and adds it to the PE fueling. Need to tune MAF down in the closed loop region so you have negative values this way no fuel is added when you go WOT. Also getting random KR which could be causing power to drop.

I would adjust MAF so LTFT are in the negative 3-5% range, raise low side pressure to 70, and fix KR.

Also, your wideband reads really erratic. Never seen one do that.

This post is very helpful to me thanks King

[KingLT1]

Originally Posted by Kerry

This post is very helpful to me thanks King

[ANTHONYL79]

So found the issue. This build had new injectors 8 months ago. For some reason injector for cylinder 6 decided to take a dump. Got new injectors in and installed a ZL1 low side pump. Car is running way better, but new issue with cylinder #5 and bank 1 LTFT. During the pull pulse width on injector 5 goes to zero. I am wondering if I have another bad injector again. Didn't have the channel log on the last setup to show that.

[toohighpsi]

Are these stock GM injectors? That left to right bank trim scares me.

You need to log less useless channels, you've overloaded the CAN bus with requested data that the data rate is too slow to see what's going on. If it's a channel that doesn't have (SAE) in the name, then it's being requested, remove some of them (without SAE) that are not being used from your list so you can get a faster data rate.

[ANTHONYL79]

Originally Posted by toohighpsi

Are these stock GM injectors? That left to right bank trim scares me.

You need to log less useless channels, you've overloaded the CAN bus with requested data that the data rate is too slow to see what's going on. If it's a channel that doesn't have (SAE) in the name, then it's being requested, remove some of them (without SAE) that are not being used from your list so you can get a faster data rate.

Stock LT4 injectors, just got them back from getting 1 warrantied and the rest of them checked out. All new seals.

I updated the channels list. Let me know what you think.