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First Drive With MS3, Tune/Turbo Trouble

Old 04-15-2012, 11:43 PM
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Default First Drive With MS3, Tune/Turbo Trouble

Went for the first drive under the MegaSquirt III. I was going to do this a few weeks ago, but it would die every time I hit the throttle. I solved this by raising the RPM via the idle adjustment (blowthrough?) screw, bringing it up from 700 to 950rpm. That solved the crankyness and the stumble at sudden acceleration.

It drove ok, but I seem to get an occasional misfire. It only happens at low rpm, it seems, and once in a while. I did not see anything on the logs, so did not change any settings. I then plugged in the last piece of the turbo plumbing, and gingerly started it. Nothing different. Runs pretty much the same, but no noticable boost.

I attached my log from a short run, with two few-second stomps on the pedal. I also attached my current setup.

I'm pretty much at the limit of my understanding on this. My dad is better than I am on this, but neither of us have much knowledge about turbocharging. I understand the basics, but do not know what I need to modify/adjust with the MS3.

Also, I have the wastegate plumbed to the EBC, then to the intake manifold. I have a hunch that's why I was not passing 0.8psi, and constantly showing vacuum. I need to install a fitting before the intercooler once I can find one. The BOV is also plumbed directly to the intake manifold behind the TB, but that should be fine.

Any ideas here?

BTW, information on the build is in the build subforum somewhere.

1996 BP05 on a 1994 harness, MS3 with EBC, 38" equal length primary turbo manifold, SR20DET intercooler and BOV, 305cc injectors (yes, I know, I know).
Attached Files
File Type: msq
CurrentTune.msq (139.1 KB, 84 views)
File Type: msl
2012-04-15_21.35.11.msl (1.08 MB, 86 views)
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Old 04-15-2012, 11:55 PM
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what wideband are you using or are you using a narrowband?
also for intial tuning you should disable any and all corrections, IAT correction, baro correction, acceleration enrichments, and if you don't have a tuned idle control scheme disable any type of idle and just the idle screw to manage your idle for now until you have a tuned in fuel table.
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Old 04-16-2012, 12:57 AM
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BOV is behind the throttle body? How is this possible? I assume you're talking about the signal hose.

WG signal needs to be un-throttled.

The tune looks like it should drive but that's all dependent upon ReqFuel and things like that. Get it idling, go from there.
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Old 04-16-2012, 02:15 AM
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I used the idle screw to adjust it to a functional idle. We haven't changed anything much from the base Miata tune from DIYAutoTune, other than delete the IAC.

Oh, BTW, I deleted the IAC and EGR.

As for the BOV, it's located before the intercooler, and the vacuum line is plumbed right behind the throttle body, on the manifold. The WG is plumbed right next to the BOV line.
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