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Fully built SR20det VVL on AEM V2 going wicked lean

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Hey forum! First time posting and glad to be here.

I have a fully built SR20det with a P11 head being ran by an AEM V2 Nissan ECU. The engine just got a full rebuild and has been switched over to E85.

During dyno tuning she feels great until after a couple pulls and then she goes crazy lean across the board. We have added fuel system parts and checked over everything we could think of mechanically and still can't figure out what's going on. Fuel pressure to the rail is good.

Would anyone be willing to take a look at the calibration file and a couple logs to see if we have possibly missed something in the tune?

The build specs (fuel pump and a couple other parts have been updated since the list was made) can be found here: https://www.containedchaos180.com/rides

You can see pics on my Instagram at @Contained_chaos180

Calibration and log files here: https://drive.google.com/folderview?id=1rPXURTKfRnJpJUzFF3u1rcCK2MWl5H2T

Thanks in advance!

Are you logging fuel pressure during runs or just checking a gauge with pumps on? It sounds like pumps cavitating with heat or temperature sensitive gas (As in actual gas state of matter as you are US) injector issues. Do coolant and intake temp compensation look ok? I'm not familiar with the AEM fuel model, does itself compensate for inlet temp and the corrections are minor trims?

Yes, monitoring fuel pressure with a sensor at the regulator. Fuel is straight e85 with a new AEM pump that should run cool. Still happens even with a full tank. Not sure about compensation as I'm not a tuner yet (still learning) but the logs should show that.

Anyone look at the logs?

Hey Nick,

I tried to take a look at your logs, but I can't access it as your google drive access seems restricted.

Thanks for the heads up Frank. I went ahead and made the folder public. You should be able to access the files now.

Anyone have a chance to look at those logs?

I took a look at the logs. A couple point :

1. Your IAT values are fluctuating a lot, I don't know if it's because you have a fast reacting sensor (never logged one personaly), but from 66F to 93F in 0.7sec at idle. This shows on both logs. (just curious about this) Also, your 2nd log shows higher IAT level, which could lean out your values for sure.

2. The coolant temp are a bit different on both log, the lean one being cooler, which should have shown about 3% richer according to your fuel coolant trim.

3. At the beginning of your first log, you were already rich at idle.

4. Have you changed anything between the 2 logs? Any parameter, or anything physically on the engine? They are only 5 min apart. What did you do during this time?

5. Where these logs done on the dyno or on the road? Did you load the dyno the same way both time? Used same gear?

6. Fuel inj1 Pulse looks pretty much the same for the same load and throttle opening. Do you feel the car hesitating or could you feel some misfire?

7. Were the car running for the same amount of time before you started the logs (for afterstart enrichment compensation).

I'm still learning and I hope someone else will chime in to discuss about this! But for me, it's hard to find something wrong looking at your logs.


Hey Frank, thanks for the reply. The AEM software keeps stopping my life and opening the "save as" window. We're not sure what's causing it but it has done it on multiple computers. So I just try and get whatever logs I can without driving it too much in this condition.

Nothing was changed between logs. Both were on the street fitting the same short drive. I'll be uploading another more recent log to the drive tonight.

3 more files have been uploaded. These logs are during a remote tuning session via team viewer with my tuner. He was making adjustments the entire time.

Anyone have a chance to look over these logs?

We usually reply within 12hrs (often sooner)

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