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Old 02-16-2011, 09:17 PM   #1
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Default Car won't stay running

I can't make sense of this, my car catches and fires fine but dies 1-3 sec after. It's does this with 15 sec fixed ASE and with decaying ASE (both ways previously worked fine).

It will stay running if you feather the gas but gets really lean and will idle on it's own every 20 or so start attempts. I assumed the random stalling and non starting that cropped up in November (out of nowhere) were a result of a bad fuel filter but the new one hasn't corrected it.

The car decided to behave this way just before being put away and the only thing done to it within 6 months was a new soft top.

See logs, one starts with the car running the other is several start attempts.

EDIT: other "clean" msq's behave the same way and with the factory ecu in it runs (poorly due to the 600cc injectors)
Attached Files
File Type: xls datalog201102161717.xls (36.5 KB, 34 views)
File Type: xls datalog201102161722.xls (210.9 KB, 38 views)
File Type: msq megasquirt201102162029.msq (35.2 KB, 74 views)

Last edited by inferno94; 02-17-2011 at 08:46 AM.
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Old 02-16-2011, 09:39 PM   #2
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What is your method of sensing airflow/manifold pressure?
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Old 02-16-2011, 09:41 PM   #3
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Quote:
Originally Posted by fooger03 View Post
What is your method of sensing airflow/manifold pressure?
MAP sensor in the ms, there is a second one for baro and it's ms1 by braineack btw.

You're suggesting vacuum leak? I didn't find any in the short time it ran today.

Last edited by inferno94; 02-17-2011 at 09:29 AM.
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Old 02-16-2011, 09:49 PM   #4
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Wanted to make sure you didn't have a failing MAF - but it's not possible to have a failing MAF if you're not using one.
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Old 02-16-2011, 09:57 PM   #5
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It's just so strange this problem has progressed from the occasional miss at speed to temporary loss of power at speed to occasional non starting to shut down at speed that won't restart.

Now it doesn't want to stay running and if it does it has afr's all over the place then 18-19:1 lean with nasty exhaust.

I think it's some hardware failure but I'm not sure what. On a side note my MS decided not to turn the fans on anymore around the time this started so they are now wired to be on all the time the key is at on. The other day it also changed the cranking cell corresponding to the current outdoor temp to 0.1pw from 4pw on it's own.

Last edited by inferno94; 02-17-2011 at 09:28 AM.
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Old 02-17-2011, 08:08 PM   #6
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Need more info to hazard a guess?
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Old 02-17-2011, 10:23 PM   #7
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18-19:1 lean w/nasty exhaust - both of these are symptoms of the misfire, not causes - a car running pig rich, but misfiring, will show a lean condition on the AFR - nasty exhaust is you blowing unburnt fuel out. Pull the plugs and tell us what they look like. Turn the engine with plugs pulled and tell us if liquid shoots up out of any of the cylinders.

When was your last plug/wire change?
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Old 02-18-2011, 11:23 AM   #8
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Plugs were fairly fouled but I noticed something else, batch #2 injectors are injecting 2x as much fuel as batch #1 all the time (according to megatune) thus my afrs being a wavy line.

Question is how to correct this and why would this happen? Firmware corruption?
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Old 02-18-2011, 11:39 AM   #9
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This is where my brain stops, and someone else chimes in...
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