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Thread: rich start up problem with 3bar OS

  1. #1
    Tuner in Training
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    Mar 2008
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    rich start up problem with 3bar OS

    I have been running my car on 2bar speed density for a long time now without any real problems at all. Decided its time to run more then 15psi of boost so I went and upgraded the OS to the 3bar OS. (I converted back to the original tune file first, then converted over to the 3 bar OS.) And yes I did a write entire when switching things over. The problem is, when I go to crank it over for the first time, it goes pig rich. So rich in fact that black smoke puffs out of the exhaust. I've tried re-converting it to 3 bar with the same results. When using the scanner, I notice that the PCM is commanding a huge amount of fuel, (as seen in the pic.) I converted the car back to a 2 bar and everything works fine with that. (yes I switched the map sensor over from a 2 bar to a 3 bar.) Any idea's? suggestions? Thanks

    securedownload.jpg

  2. #2
    did you try to pull any fuel from startup enrichment or from the VE table to see if it helped?

  3. #3
    Tuner in Training
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    As silly as it sounds, I have not tried this yet. I thought that what was good for the 2bar map, would be good for the 3bar map. Its always the little things that you forget to try. I'll give this a try tomorrow night, Thanks for the suggestion!

  4. #4
    report back when you try it

  5. #5
    Tuner in Training
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    Mar 2008
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    All of the ECT tables are at 0, and I took the VE table and changed all the cells in the area where the car starts up and idles to 50% of what their original values were. crank it over and get the same results, instead of a value of 43.7 in he INJB1/2, I get a value of 35.1 instead. Still way too rich to start up. So I go in the VE table again and remove 25% more fuel. At this point the numbers in the VE table are in damn near single digits. And I get the same results when attempting to crank it over. Switched everything back to the 2bar OS and it starts up no problem. INJB1/2 values with the 2 bar OS, are about 12-15 while cranking, and drop down to 5-6 after it starts up, then they level off around 1.5-2 while idling.

  6. #6
    someone with a little more experience is going to have to help you i had a similar issue with a lsx turbo s10, except it did it in 2 bar and 3 bar, 1 bar was the only thing that made it okay it pegged the gauge rich i never figured it out so i have the truck posted for sale just needs a tune and a few small ods and ins lol

    i was hoping it was something easy

  7. #7
    Tuner in Training
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    Have you tried using another PCM? I've got another one in another turbo 5.3 vehicle that I've got. Maybe I'll try it out on there and see if it makes any difference.

  8. #8
    well I swapped the s10 pcm into my lsx mustang and copied the tune from the mustang pcm to the s10 pcm, fired it up pig rich , so I just put the old pcm back on I think the computer is bad or something

  9. #9
    Tuner in Training
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    Oct 2009
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    I was haveing the same problem, I turned off my short term fuel trims along with the long term fuel trims and no more rich start up.

  10. #10
    Tuner in Training
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    Just tried converting my other car to a 3bar SD, and get very similar results. Car is way too rich to start up due to the PCM giving too much injector PW. ugh...

    Wildside - If you turned off all your fuel trims, do you just run the car in open loop all the time then? Sounds like it might not be the correct fix.