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Old 01-29-2011, 03:08 PM   #1
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Default MSPNP Startup RPM Overshoot

I have a little refining to do on my cold and warm starts, but I have a question about after the engine cranks. Once the engine starts, it runs up to roughly 3000rpm for a few seconds prior to settling to the anticipated warm-up or warm rpm. It may be that I haven't driven the car for a little while, but does this rpm sound normal, or do I need to adjust my tuning to keep it down a little lower?
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Old 01-29-2011, 04:07 PM   #2
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There are a couple of things that immediately spring to mind, alghouth 3,000 RPM doesn't strike me as terribly excessive. More than stock, yes.

The first is the idle "Cranking(dc)" parameter. This sets the IAC valve to fixed duty cycle while RPM is below cranking RPM. I honestly can't recall whether this value decays out or merely hard-switches once RPM is > CrankingRPM.




Then, under ASE, you have a bunch of parameters that affect engine operation immediately after cranking ends. (This is another fun screen where the "default" values aren't the defaults.) Specifically, the whole "Fixed MAP" section comes to mind. This is where we sort of lie to the system and tell it "For x number of seconds after startup, I want you to ignore what the MAP sensor is telling you and just pretend that the MAP value is xx." If the fixed time period is too long, or the fixed value is too high, it might cause the sort of thing you're describing.

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Old 02-02-2011, 12:17 PM   #3
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It may be the cranking dc. For my 1.8l, I kept the cranking dc at MSPNP defualt of 12, whereas I have adjusted the min/closed dc down to 5/6. I'll see if lowering that does the trick. Thanks for the help, Joe.
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Old 03-16-2011, 08:59 PM   #4
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I want to follow-up quick with the success I had with your suggestions.

The ASE I left unchanged and ended up lowering the cranking (dc) settings. Overall, I reduced the cranking, minimum and closed a value of 2. It's almost warm enough to be able to do some testing to pinpoint the actual closed value, but the car starts and runs much better after adjusting all three.

More good news:
I installed a Westco battery and recalculated the ASE Table for fuel. I reduced the fuel an average of 10-15% from my original values. The combination of these two changes helped cold starts go from from 7-10 seconds worth of cranking (essentially draining the old battery) down to 2-3 seconds to crank.

In the third run of good news:
I was pissed when I went to do the software changes three weeks ago. I found that my Windows XP full version of TunerStudio cannot locate the correct registration/configuration file on my VMWare virtual drive. As most know, the full version is more or less essential to review and send/burn my new changes to the MS (without ripping your hair out to do it manually). This past weekend, I uninstalled everything, redownloaded the Mac files, and found that it works perfect now on my Mac OSX 10.6.6. I was absolutely ecstatic about that! I can now run and tune for hours on the Mac, whereas I was limited to about 1.5 hours total battery life running TS in VMWare.

Last edited by Enginerd; 03-16-2011 at 09:10 PM.
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