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Old 04-04-2010, 07:56 PM   #1
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Default MS-1 Lean idle on warm startup?

Have a turbo 1.8 w/ braineack standalone MS-1. Using LC-1.
Currently using cranking PW's I got from brain and the car starts up fine.
Using a GM open element IAT sensor located right before the throttle body, 460cc RX-7 injectors.

I'm currently on a Tunerstudio generated basemap for 460cc injectors. Had this same problem before I went boost though?

Cold starts the car starts fine, and is obviously rich at idle but nothing out of the ordinary, but after I've driven the car for a while (get up to operating temp) with no difference to ambient temperatures the car starts up and idles around 18-20afr but its not consistently on every startup only an intermittent problem. I've searched the threads in here to try find a similar problem and have found some and tried the solutions recommended but no fix for me? It seems as if I start the car and I get those symptoms above if I rev the car out or start to cruise down the road it will temporarily stay in the lean area 15-17afr until I actually add some throttle then things straighten out for the rest of my drive?

Not too sure what info you more experienced users need to help figure it out so im attaching my MSQ for you to pick apart, along with a log from before the boost setup was installed, as you will be able to see the slightly lean afr starting. For whatever reason I cannot re-create the issue to be able to log it yet.
Attached Files
File Type: msl idle.msl (16.3 KB, 52 views)
File Type: msq turbo460base1.msq (32.8 KB, 45 views)
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Old 04-06-2010, 12:49 PM   #2
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That just looks a little bit lean, not the 18-20 AFR. I'd really like to see if you could reproduce the following:

1. Have it idling very lean.
2. Rev the engine and have it settle back to normal.

Getting at least #1 would be a bit help. Unfortunately, gremlins seem to run and hide every time you pull out a laptop to data log.
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Old 04-06-2010, 01:06 PM   #3
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I'm sure it's heat soak related. Your log shows the sensor sitting at 76*, i bet it got over 90* the time you noticed the problem.

Change the CLT-Based air density table to correct for AIT, and then add in fuel where the temps cause you to go lean on startup.
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Old 04-07-2010, 12:09 AM   #4
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I've noticed the same thing at an auto-x and I was assuming that it is heatsoaked IAT. Clears up by the time I stage and start my run.
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Old 04-07-2010, 01:21 AM   #5
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ive been getting this lately too , only if i run for a while, let it sit and go to start it again, before the iat gets back to around 70ish... so you just mess with the clt based air density? what are some peoples settings?
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Old 04-09-2010, 01:28 AM   #6
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Quote:
Originally Posted by Matt Cramer View Post
That just looks a little bit lean, not the 18-20 AFR. I'd really like to see if you could reproduce the following:

1. Have it idling very lean.
2. Rev the engine and have it settle back to normal.

Getting at least #1 would be a bit help. Unfortunately, gremlins seem to run and hide every time you pull out a laptop to data log.
A little lean as in the whole map?
Seeing 10.5-11.5 under WOT to the redline. About 10.1ish around light load/cruise though, sorta rich eh?
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