Hello I'm new to tuning V3 so for now I've just been tuning it like you would in V2 using the sliders. Yes I will be using the tables when I resolve this issue. Basically its been leaning itself out at around 1900Hz and only getting worse and worse. Ive tuned around it so that it can progress to the point where something might be obviously wrong. Around that frequency at 30 psi the car misfires now as well. That symptom is new. It gets worse as the air gets colder. I have new BR7ES plugs in the car. NGK plug wires that are a year old and the car is on E85. If I turn the boost down at all it doesn't miss. The car leaning itself out consistently and only in one RPM range is very weird to me. Compression was 165 across the board. Heres 2 logs I took with the issue happening. I let out right after it happened but if I keep in it it clears up. Happens around 6300RPM and 1900Hz-2100Hz or around there.

Thanks to all who chime in!

1). No boost, vac, or exhaust leaks.

All Good Here.


2). Verify mechanical timing.

Done

3). Verify base timing

Done

4). Ignition system

Tried .022-.018 with no difference what so ever.


5). Motor health

165 164 166 166

6). Basic throttle body adjustments.

5V at WOT.

7). Compression ratio

8.3:1

8). Wiring and sensors

No issues I'm aware of

9). No DTC/CEL codes

For the Speedo cable. It broke and I'm waiting on a new one.

10). Electrical system

According to link, it drops into the 12v range at WOT otherwise is 13-14v

11). Base fuel pressure and injector values

42.5 psi and FIC 1250cc

12). Properly calibrated and configured wideband sensor

Yes, AEM UEGO set up under linear WB with the ECMLINK buffer soldered in

13). Type of fuel

E85

14). ECMlink how-to videos

nothing that helped solve my issues

Im at work so I can't look at your log right now. But try gaping your plugs tighter. like 0.016. You might be getting spark blow out. Worth seeing if it goes away.

jakk220 said:

Im at work so I can't look at your log right now. But try gaping your plugs tighter. like 0.016. You might be getting spark blow out. Worth seeing if it goes away.

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That's what I thought to but when you open the log you'll see under maf comp I've slowly had to add this weird hump at that MAF freq. if you get past that hump the car usually clears up. Going from .022 down to .018 made absolutely no difference at all. I'm gunna try swapping plug wires with other ones but that's still doesn't explain the leaning out issue.

It certainly doesn't help that the battery voltage is so low.

Vegas smith said:

It certainly doesn't help that the battery voltage is so low.

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I'll do a peak to peak min voltage test during a pull and see what it really is

Ok voltage test came back showing 13.6 volts was the lowest it dropped. Beefed up the ground on the intake manifold too just cuz.

Unplugged the plug wires from coil and cleaned and regreased them. Definitely helped out but still an issue especially when cold outside. Tried new NGK and then ACCELL wires with no change at all from mine.

Did a leak down test too with really strange results.

Cyl#1- 4-6%
Cyl#2- 3-4%
Cyl#3- 2-2.5%
Cyl#4- 2.5-3% with some bubbles occasionally in coolant

Tested 3 times at 75psi inlet, 3 times at 90psi inlet, and 3 times at 100psi inlet. Made sure the compressor was pumped up fully before each test and regulator was set 10psi above what the leak down tester was set at.

Don't understand how there could be bubbles and still such a small percentage of leakdown in Cyl#4 tho.

Richness it up through misfire zone and AFRs read 11-11.5 through there.

Funny story, I actually had a misfire that I could not diagnose for over a year. Turns out that I had a tiny (and I mean tiny) head gasket leak that was going into the coolant system. It was so small that it would push coolant, but not to a point that I ever lost any out of the reservoir. It eventually got bad enough to manifest itself, and once it did and I replaced it the misfire went away.

If you are getting bubbles in the coolant when doing a leak down, even a tiny amount of them, it is a good possibility that this is your issue. I thought about this when I first read the post, because I had the exact symptoms (got worse in the cold, cleared up in high rpm, etc.) and my logs looked identical. I just did not want to jump to the blown head gasket conclusion as it was kind of a long shot.

Are you noticing a loss of coolant at all? Take the coolant cap off on an ice cold start and look at the coolant, are there bubbles?

It's a cometic MLS I did when I did the timing job. I'm gunna try retorqing it just for fun but I'll go through like a gallon every few days.

On a cold start I don't see any bubbles.

And no mixing in the oil is there Chump? Was the head nice and flat for that Cometic MLS?

Chumpaumpalumpa said:

It's a cometic MLS I did when I did the timing job. I'm gunna try retorqing it just for fun but I'll go through like a gallon every few days.

On a cold start I don't see any bubbles.

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You can give it a shot. When you do a MLS not only do you need to mill the head and deck the block, but there is also a RA spec that must be met. And that gallon every few days I am willing to bet is coming out of the overflow.

Mine at first would not show bubbles on a cold start either. It was only pushing the coolant at high boost levels. Other than that it was not noticeable, which was why it took so long to diagnose. The leakdown test pretty much confirms that there is an issue with the headgasket though. Which sucks.

It's not. The overflow tank is always at the same level.

This morning when I started it the #3 injector wouldn't fire. Fixed itself after starting it a few times......

The head came off 2 years ago for a timing job and didn't drink any coolant for 2 years. The head was decked and RA50 and the block was flat with less than 1 thou variance.

And no water in oil or vise versa.

Maybe more than one thing going on.

Were you making adjustments during 1.28.01 log?

tk106 said:

Were you making adjustments during 1.28.01 log?

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Nope they're back to back pulls too

RPMs are all over the place at idle while coolant temp is steady. Is your wideband on the 02 housing?

You hit almost 30psi at 4700 and only 13psi towards the end of the pull. Are you sure there's no boost and or exhaust leaks?

Wideband and AFratioEst are way off also.

tk106 said:

RPMs are all over the place at idle while coolant temp is steady. Is your wideband on the 02 housing?

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Throttle body does not close right all the time. It's also cammed so that doesn't help. WB is in downpipe, still have front O2 in stock location.

tk106 said:

You hit almost 30psi at 4700 and only 13psi towards the end of the pull. Are you sure there's no boost and or exhaust leaks?

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That's not right. The gauge touches 30 and tapers to 25-27 by redline. I can check for exhaust leaks more thoroughly and boost leak testing it holds 35 psi and if I cut the pressure it tapers down nice and slow.

tk106 said:

Wideband and AFratioEst are way off also.

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I'm tuning using the sliders and MAFComp for now until this gets fixed so I'm ignoring whatever the tables are at so they're going to be off. I don't want to put all this work into making the tables all smooth and perfect then have to change them again when the issue is resolved.

Think I'd start with fixing the sticky throttle.
You have 1200cc injectors, but this might be a problem on the site and not your fuel settings. Something you can double check.



Just curious. Why did you pull timing?

If the car is mechanically up to par, I'd start with dialing in MAF and see if that corrects leaning out issue.

Injector duty at 6k is 78% and starts dropping after that also.

Does anyone know if he need a bigger fuel pump??? He has wally 255 & 1250's

tk106 said:

Think I'd start with fixing the sticky throttle.
You have 1200cc injectors, but this might be a problem on the site and not your fuel settings. Something you can double check.

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Just curious. Why did you pull timing?

If the car is mechanically up to par, I'd start with dialing in MAF and see if that corrects leaning out issue.

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I've seen it do that a couple times after after telling it what size injectors I have. When you put the right size injectors in the global fuel scale doesn't change though so I think it's just a fluke. Definitely will check again though. The car is no longer leaning out because I've been tuning around it but that weird bump in maf comp around 1900 Hz was not there it was flat and smooth like the rest of the graph after it. It started leaning itself out around that area and I've had to raise maf comp, more and more and more. Seems to have stopped doing that tho.

Pulled timing because I'm using the sliders ONLY to tune for right now. Haven't touched the Maps yet.

tk106 said:

Injector duty at 6k is 78% and starts dropping after that also.

Does anyone know if he need a bigger fuel pump??? He has wally 255 & 1250's

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All I know about fuel pressure is base fuel pressure. Maybe something to look into

Glad she’s running better.

You’re fine if the global calculation is correct. I had a log posted and for some reason other members saw a different inj size then what I actually had in link.

Now that I think about I wonder if your injduty decreasing is bc your boost was tapering down. Really curious as to why it’s doing that

tk106 said:

Now that I think about I wonder if your injduty decreasing is bc your boost was tapering down. Really curious as to why it’s doing that

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It's been running fine just the misfire and something caused it to start leaning out all by itself and get progressively worse and worse. That's what I'm trying to find.

Chumpaumpalumpa said:

It's been running fine just the misfire and something caused it to start leaning out all by itself and get progressively worse and worse. That's what I'm trying to find.

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If that leak down test shows bubbles in the coolant, then I am almost positive that you already have your answer. Your log looks almost identical to what mine did when I had the same issue. If you are not losing coolant in the overflow yet, it could just be because the leak is currently so small. Also you may be losing your coolant by burning it. Just in a very small amount.

Even some people that do the head gasket 100% by the book have issues getting MLS gaskets to seal.