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poor running 1990 TR

Discussion in 'Technical Q&A' started by mjcdc, Aug 31, 2004.

  1. mjcdc

    mjcdc Rookie

    Jun 8, 2004
    5
    colfax california
    Full Name:
    mark
    I posted awhile back about a gradual loss of power (it seems, it's been so long since i drove it). The vehicle seems to have slowly loss power and seemed to run a bit warmer than usual. I first checked the exhaust for equal heat. The 1 - 6 bank does not warm up at all! I have spark, I swapped fuel pumps, new fuel filters, swapped ECUs for electronic ignition, checked distributor cap and swapped coils with no change. Now pulled out O2 sensors and pressure out of 1- 6 is definitely weaker (about 80%, by pressure to hand). Although seemed to run smoother. Dropped pre - cat on 1 -6, found nothing in there, like it was already cleaned out and ran car with pre - cat disconnected and made no difference. Now noticed about 50% heat in forward header (cyl 1 -3) compared to header on 7 -12 bank, while 4 - 6 header stays room temperature, no heating up at all (not sure if just never noticed this or never checked it before or do to removing O2 sensor). Checked cam timing and it is fine. Checked vacuum at rear of intake plenum, cyl 1 - 6 (cold side) has a bit more vacuum than 7 - 12 bank.
    HELP, if anyone has any ideas?

    mark
     
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  3. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,086
    Austin TX
    Full Name:
    Brian Crall
    There are only three thing required for a motor to run, Compression, Fuel, and Ignition. There are no shortcuts in diagnosing a poor or non running motor. Take a compression check, all twelve cylinders. Hook a timing light to all twelve, one at a time (easiest way if you don't have a lot of equipment). And then the fastest way to check for fuel is to test the cylinders with an exhaust analyzer. You probably don't have one of these at your disposal, but by process of elimination if you have compression and ignition you can figure that one out. Any other process is just guess work. Try that and get back.
     
  4. Boxer12

    Boxer12 Formula 3

    Jun 1, 2003
    1,672
    So, you can have an entire bank out and no idiot lights to warn you? geez
     

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