E38 PE Issue. Lean 2.1 Seconds. Can we solve this?

[Montecarlodrag]

On the 2 logs I opened the worst lean condition is on different bank, however they are split by the same amount. There is a correlation here.
You are logging a lot of useless PIDs, try to make your datalog more useful deleting everything you don't need and focus on useful PIDs and increase polling frequency.

In both logs I can see a negative fluctuation in the air entering the engine, the MAF picked it on 1 log and the dynamic airflow on the other log. This suggests me that something mechanical or electrical is acting up.
Since PE remains active, injector pulsewidth isn't falling, fuel pressure doesn't drop and the ECM doesn't change commanded AFR I think it's possible that the lean spike is caused by a misfire or spark blowout.
The only obvious thing I can see in the log is that the voltage is very low, like you are running on battery only. In one log voltage is low until you go wot and the rpms rise it goes to 14.7X Volts, then it goes low again just before the lean spike. On the other log voltage is just fluctuating. It seems that you have an electrical problem. Voltage shouldn't fluctuate that much and anything below 13.5 V at wot is a problem.

I'd first check grounds, alternator and battery, then put new spark plugs with a smaller gap to rule out spark blowout.

[BigDaddyCool]

Well I've had it. The problem is PE full stop. I've been testing this for 3 months now.

I did both an OL EQ Test, Airgain and Stoich. Worked fine.

Using PE or even Boost Enrichment to get in in OL from CL and using a airgain to command the AFR didn't work.

Basically using anything in the PE tab has this problem. God forbid I had a supercharger or turbo I'd be stuffed......

HPTuners is clearly missing something from PE!!!! It's absolutely crazy. It's like PE disengages and then reengages without showing on the scanner.

I recon I have a partial solution to this...... PE when it disengages converts back to stoich at the same speed as the enrichment rate. Therefore if I slow down enrichment if it's doing what I think it should greatly diminish the issue. The downside being I cant put power down as fast.

[BigDaddyCool]

Alright so the solution is DAMN SIMPLE to sort this out - possible? Upto the HPTuner guys.

It needs what the 2015 Corvette has. Enrichment Ramp In and Enrichment Ramp Out. That way I can set in to 1.0 or 2.0 etc and out to 0.0100 to stop this from happening.

Guess what EFI Live has? ........ everything that could be effecting my PE including a ramp out option.....

[Chris@HPTuners]

Alright so the solution is DAMN SIMPLE to sort this out - possible? Upto the HPTuner guys.

It needs what the 2015 Corvette has. Enrichment Ramp In and Enrichment Ramp Out. That way I can set in to 1.0 or 2.0 etc and out to 0.0100 to stop this from happening.

Guess what EFI Live has? ........ everything that could be effecting my PE including a ramp out option.....

Changing the ramp rates is not a good solution, we'll work this out, i just sent you some things to try.

Chris...

[Niemer]

Please read from post #156 on in this thread, there is an actual measured (with a 'scope on a dyno) injector pw drop when this occurs. For some reason the OS is cutting fuel.

https://www.hptuners.com/forum/showt...l=1#post462627

[Chris@HPTuners]

I have added PIDs to log the PE EQ Ratio and also all 8 Injector PW values just before they are written to the hardware driver, so we will hopefully find some more clues soon. If you have the 12633016 OS you can download 3.5.625 or later and try it yourself.

[Niemer]

Once I get beta access I'll get some logs.

[GHuggins]

Changing the ramp rates is not a good solution, we'll work this out, i just sent you some things to try.

Chris...

Chris, would it be possible to have the ramp in and ramp out rates added too I'm pretty sure thinking back that I've had this issue on two other E38 equipped vehicles - one I'm fixing to retune this next week - OS -

12635863 -> 1250230 I always just figured it was the turbos starting to spoil... Don't have time to experiment on it, but might be able to get a log or two if you like... Then the other was actually doing the opposite - going richer than commanded after entering PE causing a rich stumble - was able to fix with transients and PE settings, but...

[Chris@HPTuners]

Chris, would it be possible to have the ramp in and ramp out rates added too I'm pretty sure thinking back that I've had this issue on two other E38 equipped vehicles - one I'm fixing to retune this next week - OS -

12635863 -> 1250230 I always just figured it was the turbos starting to spoil... Don't have time to experiment on it, but might be able to get a log or two if you like... Then the other was actually doing the opposite - going richer than commanded after entering PE causing a rich stumble - was able to fix with transients and PE settings, but...

I added the PE ramp out rate and the PIDs: Equivalence Ratio PE, Inj PW Cyl 1 ...8

3.5.626 or later

[FASSTRUK]

Did you try increasing manifold volume in the transient tab? Like .05 percent,

[GHuggins]

Did you try increasing manifold volume in the transient tab? Like .05 percent,

He's tried everything that I can think of... I even made some tables for him for the tq model and everything else - nothing works except for killing PE or rather taking it out of the picture...

What about ramp in rate Chris? Think that might possibly be more important here???

[Chris@HPTuners]

He's tried everything that I can think of... I even made some tables for him for the tq model and everything else - nothing works except for killing PE or rather taking it out of the picture...

What about ramp in rate Chris? Think that might possibly be more important here???

Its already there

[GHuggins]

I thought it might have been a different kind of timed ramp in or something My bad... Just downloaded the latest - only benefit I can see with the ramp out would be one of two - either have it slowed down in which you might run into a different problem where the leanout is possibly made worse or speed it up where the leanout would possibly be shorter lived? Correct assumption here Chris?

[Chris@HPTuners]

I thought it might have been a different kind of timed ramp in or something My bad... Just downloaded the latest - only benefit I can see with the ramp out would be one of two - either have it slowed down in which you might run into a different problem where the leanout is possibly made worse or speed it up where the leanout would possibly be shorter lived? Correct assumption here Chris?

Well the issue is that the ramp out rate applies when you exit PE so if you set it very small it will take a long time to return to stoich. The PE code runs at 50ms rate so if PE is dropping you will see it in the scanner for sure, either the PE status or the PE EQ ratio, commanded Afr etc. I think something weird is going on here. I have owned two E38 LS vehicles both supercharged and never seen this problem. One was an 09.

[BigDaddyCool]

Ran the suggestions this morning on a 10ms rate........ still spikes but nothing out of place. I will do it again this arvo on my way home....... and have a closer look tonight. But so far everything looks like it's fine. PE doesn't drop, all the injectors show the same PW virtually... PE EQ Ratio is fine.... if I was to pick anything, it would be timing and or a bunch of trickle knock... rather small but.... I'll post up a few logs tonight.

If the engine reports everything as OK, maybe the exhaust both sides are leaking at the engine?.... I'm at work at the moment. I'll post some logs when I get home.

[BigDaddyCool]

Here's some logs. I cant see anything. Two of the three log all the o2's, one only logs bank 1.

I'm absolutely stumped. The only three things I notice:

1. Manifold vacuum constantly is 0 and 1.
2. Sometimes there's KR.
3. The injectors can vary by .1 across 2 to 4 of them which might be normal I think.......

PE and everything else stays flat on.......... this is 10ms resolution.

When it does lean out, depending on the log it could be either side of the exhaust that goes first..... so I don't think it's a lean on any side either etc. Like I said it doesn't do it when commanding it in OL without using PE.

[GHuggins]

Any self test going on entering PE Chris?

[Chris@HPTuners]

I think i have found the issue, hopefully testing confirms it

[Niemer]

[GHuggins]

I can test it to if you need me to Got one on the dyno right now doing the same thing - E38 twin turbo 2010 vette... I was able to manipulate a lot of things and get it to where it only leans out to 13.5ish though...