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308 turbo wont start

Discussion in 'Technical Q&A' started by 4returbo, Dec 18, 2003.

  1. 4returbo

    4returbo Karting

    Oct 14, 2003
    60
    Indiana
    Full Name:
    Rick Oliver
    I've been having turbo problems (another thread another time). Right now with the turbo removed I can't start the car. It turns over fires a a few times and will not fire again. It was running before I removed the turbo. I have the oil lines for the turbo capped off, no muffler and no air filter (I am using a clean oil soaked sock over the air in tube). Am I missing something obvious? Why won't this thing start? If you have a car set up for turbo will it start n/a without changing timing or fuel mixture?
     
  2. Verell

    Verell F1 Veteran
    Owner Consultant

    May 5, 2001
    6,951
    Groton, MA
    Full Name:
    Verell Boaen
    In principle yes, however, all the sensors have to still be in the airflow path. My best guess is that some sensor is being omitted & the ECU is deciding something's seriously wrong & shutting off the injectors and/or fuel pump after a couple of seconds.

    I've run an '87 Rx7 TurboII NA just fine while I had the turbo out being rebuilt. Had to run a tube from the airflow sensor to the intercooler input, thus the airflow sensor was in the air intake path. Otherwise the symptoms are very similar to those you describe.

    Can't help much more w/o knowing a lot more about what was being done for the turbo conversion.
     
  3. 348 Turbo

    348 Turbo Formula 3

    Jul 17, 2002
    1,837
    OK,
    Back to the air, fuel, and spark issue.
    I'd guess it's getting spark, since it is sputtering. I'd also guess it is getting fuel since the sputter. Have you tried removing the sock long enough to see if it starts? It is possible it is too rich without enough air flow. If al you did was to remove the turbo that shouldn't matter in and of itself. The turbo makes no boost at idle. I'd check all sensors and the mixture first. If your car is using MOTEC, i'd see if I could download and error. From the little you've told us, I'd guess it has notihing to do with the turbo removal. Let us know what happens.
     
  4. atlantaman

    atlantaman Formula 3
    Rossa Subscribed

    Mar 31, 2002
    1,726
    Roswell, Georgia
    Full Name:
    Charles
    To run without the turbos----

    what kind of ECU are you running? Likely it will have to be reprogrammed with a new fuel/air curve

    my electromotive has a seperate program for 1 bar, 2 bar, and 3 bar as well as different sensors to use.

    you will need a new MAP sensor to read vaccuum instead of positive pressure, a new program fuel/air curve, and I have to wonder----do you have low compression pistons wo go with the turbos???

    this might require a lot of tuning
     
  5. atlantaman

    atlantaman Formula 3
    Rossa Subscribed

    Mar 31, 2002
    1,726
    Roswell, Georgia
    Full Name:
    Charles
    your old map sensor is looking for + prseeure and now you have a vaccuum to it- i believe the only reason for the initial fireing is due to the cold enrichment feature that adds a little gas to get started
     
  6. mk e

    mk e F1 World Champ

    Oct 31, 2003
    11,384
    The twilight zone
    Full Name:
    The Butcher
    Some more details about the set-up would help. I like both Verell and Jeff's answers. An oil soaked sock is not an air filter, take it off and buy a filter, pep boys stocks a lot of K&N stuff. Check that all the sensor connections are correct. It shouldn't have anything to do with the map (unless it's gotten unplugged) or the ECU, going from a boost system to NA is fine, going the other way is where you would see a problem.
     

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