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Old 04-10-2007, 01:03 AM   #1
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Default Intermittent stumbling from 2800 rpm

So I have the car running on megasquirt, but i'm currently trying to tune for fuel with the stock injectors with the PWM valve still being controlled by to stock ECU. I've gone through and set my reqfuel to get my idle AFR to stay around ~14.8-15.2 or close to it. I've ran about 10 different datalogs going through different shifting patterns, running to redline and things of that sort then entering them into megalogviewer. I let MLV adjust my fuel VE table and import it into Megatune. I ended up with a decent fuel map, but the car continues to stumble above 2800 at random RPM. It'll do it under acceleration or under cruise.
I have a relatively short datalog and my current MSQ attached. Anyone mind checking it out for me to see where these spikes or stumbles are coming from.
The stumbles are the engine bogging for a second. Do i need a MAP line restrictor?
Running 029v MSnSE
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Old 04-10-2007, 01:25 AM   #2
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Im also getting an intermittent stumble between 2-3krpm on moderate load (like 60-90kpa), usually while taking off in first gear for whatever reason. Ill go ahead and give your stuff a look.
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Old 04-10-2007, 01:37 AM   #3
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it looks like poor connections, poor ground or 12v. all those red lines are resets, and at other places all the sensor inputs spike at the same time.
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Old 04-10-2007, 01:40 AM   #4
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I was just about to say something to that effect. Many of your sensors are fluctuating well beyond what they should be. Rpm signal is rough, and you had a pressure sensor spike to 220kpa.
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Old 04-10-2007, 01:41 AM   #5
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Yeah it resets like that when MS is controlling fuel because it bogs down or misfires but if i drive around with the stock ECU controlling fuel i don't have any spikes or dips that way in my datalogs.
Is my train of thought about that wrong? The only bad connection i can think of might be the ground for the CAS but like I said it's constant when the stocker controls fuel.
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Old 04-10-2007, 01:44 AM   #6
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you mean with the stock controlling fuel and MS controlling timing or what?
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Old 04-10-2007, 01:46 AM   #7
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it wouldn't be resetting because it isn't running well, it's the other way around...

your injector pwm settings are wrong, assuming stock injectors are high impedance
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Old 04-10-2007, 01:47 AM   #8
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No if I switch everything back to stock ECU fuel and spark. So that MS is just reading all the sensors. MS gets all the same inputs as the stock ECU except the CAS signals only go to MS stock ECU gets the CrankPS.
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Old 04-10-2007, 01:54 AM   #9
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Thanks Al I figured it would be something stupid like that. I'll go reflash and see what that changes.
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Old 04-10-2007, 02:19 AM   #10
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well its more than that, if your tach signal is unstable, it will mess up how it runs no matter what.

I did also notice some things you might want to adjust with your settings. I have an innovative LC1 and the EGO switchpoint is 2.33ish, its something to look into. Also, EGO correction is a very nice thing. When you get your map tuned pretty close set the target AFRs, open the ve tuning window, turn on Autotune, and go for a drive. It will automatically adjust your map slowly.
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Old 04-10-2007, 02:24 AM   #11
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HOLY **** THAT FIXED IT ALL
And the car runs awesome in boost and out of boost the power delivery is soooo much better i can't believe it.
Akarye, i'll set the voltage value for my AEM in the EG settings in a minute from their documentation. Jerry at DIY and the Megamanual both said for initial tuning to turn off EGO correction until you have a good fuel map established. I'll turn EGO back on later as well.
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Old 04-10-2007, 02:50 AM   #12
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ossum.
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Old 04-10-2007, 02:52 AM   #13
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Old 04-10-2007, 02:52 AM   #14
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hey we got quite a few peeps running megasquirt now eh?
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Old 04-10-2007, 02:55 AM   #15
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Hell yes we do. To bad most of us are spread out all over the place.
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