MSnS leaning out ~4000 RPM

[tolerate]

attachments.zip

Hi All,

I've posted this before, but i've tested this out on the dyno. the tuner had no idea what the problem could be.

Problem: No matter how much fuel we put in the VE table, the AFR keeps leaning out around 3500 rpm.

Can you MSnS Yodas figure out what's going on?

Things we've checked:
- Fuel pressure during dyno run: correct
- Fuel line/filters cleaned/exchanged
- Spark advance timing: checked with light
- AFR calibraiton (its a dyno)

I've put the dyno run datalogs and the latest tune. the last tune corresponds with the latest datalog.

Car Specs-
- 440cc/min low z supra injectors
- L28ET from 1982 ZXT
- MSnS 1 v3.0 (reflashed, problems still persist)
- LC-2 wideband
-1982 280zxt dizzy
- MSD blaster 2 igntion coil w/ inline resistor (getting hot blue spark)

Car extras:
- manual boost controller
- front mounted intercooler
- garrett turbo thing, i think 57 trim
Attached Files

[Matt Cramer]

Would it be possible to get the AFR data in the MegaSquirt as well as the dyno? That would make the logs easier to read.

You're already at 90% duty cycle at 4200 RPM - I hope you don't plan to rev it higher...

[dontz125]

Agreed. It's difficult to diagnose why a lean condition has occurred when we can't see it happening.

I don't see any obvious signs of it, but a rich misfire will cause a lean reading as unconsumed O2 rushes past the sensor. This often causes confusion as the tuner reacts to the lean reading by adding fuel, baffled as the situation only worsens.

[tolerate]

Would it be possible to get the AFR data in the MegaSquirt as well as the dyno? That would make the logs easier to read.

You're already at 90% duty cycle at 4200 RPM - I hope you don't plan to rev it higher...

Hi Matt,
Thanks for taking a look at my post, I'm not sure how to get the AFR data in the datalog, I thought you had to open the calculated fields drop down menu --> select wideband O2 AFR --> and LC-1 default. The AFR information should popout then. Is that a megalog settings thing?

SInce this post, I've taken the car to the auto electrical shop to fix a charging issue, then I took it to another dynoshop. They've had it for a month and haven't heard back from them.

edit: figured out how you calculated duty cycle % http://www.stealth316.com/2-calc-idc.htm[url][/url]
edit2: also figured out that the earliest two data logs have similar RPM limits of 4k, but lower duty cycles (11-13% vs 90-95%) the early logs were my initial logs before taking it into the tuning shop, and the last three are the ones that he tuned with. sounds like he messed up my car and took my money.

[Matt Cramer]

This should answer the question on getting the LC-2 data into the logs.

http://www.msextra.com/doc/ms1extra/MS_ ... tm#lambdas