1979 Seville fuel injection?
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5.0 and 5.7 Discussion, 1979 Seville fuel injection? in Cadillac Engine Discussion; I am trying to troubleshoot my 79 seville without much luck. The car is flooding at start. The only way ...
  1. #1
    wcwalker is offline Cadillac Owners Member
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    1979 Seville fuel injection?

    I am trying to troubleshoot my 79 seville without much luck. The car is flooding at start. The only way it will run is WOT or with the tank fuel pump unplugged.

    I have changed the fuel pressure regulator and cleaned the injectors. The injectors were fine and fuel pressure is 39psi at idle. The car sat in my garage for 2 years, when I put it away it ran fine. I did not do anything to preserve it. I hate just replacing components and don't know where to go for help.

    Chuck

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  3. #2
    The Ape Man's Avatar
    The Ape Man is offline Cadillac Owners Connoisseur
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    Re: 1979 Seville fuel injection?

    Service manual is a must. Quick check without any manual would be to see if BOTH temp sensors measure the same resistance when stone cold. The 2 sensors are exactly the same part number. Make sure you have a good vacuum signal to the ECU under the dash. A vacuum leak will make the thing dump fuel. Get a spare ECU from ebay and keep it with the car in case....
    Some people swap the 2 temp sensors while looking for replacements. 1 is much more important than the other but I don't know which.

  4. #3
    wcwalker is offline Cadillac Owners Member
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    Re: 1979 Seville fuel injection?

    Thanks for your thoughts Ape man. I got lucky and bought an ECU put it in and end of story.

  5. #4
    Jake072 is offline Cadillac Owners Member
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    Re: 1979 Seville fuel injection?

    Did you have any luck fixing the problem? What did it turn out to be? I am having the exact same issue with my '79 seville.

    Thanks

  6. #5
    Kriegar is offline Cadillac Owners Member
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    Re: 1979 Seville fuel injection?

    wcwalker
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    Re: 1979 Seville fuel injection?
    Thanks for your thoughts Ape man. I got lucky and bought an ECU put it in and end of story.

  7. #6
    Jake072 is offline Cadillac Owners Member
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    I guess I missed that post. Thanks!

  8. #7
    Zachary Smith is offline Cadillac Owners Member
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    Re: 1979 Seville fuel injection?

    I doubt the ECU was the problem. Perhaps some of the connections to it. The coolant temp. sensors has a more dramatic effect than the manifold temperature. The Haynes manual is dead wrong about the sensors, as are the companies selling new manifold sensors. The resistance in the sensors goes up with temperature, NOT down like newer
    ones. I am testing/ slash installing a coolant and a manifold "guitar pot" that can be tuned in the car. This gives you full control of fuel mixtures as you go. Very simple, cheap, and easy to do.

    You are welcome to kick me in the head and correct me if I'm wrong, however, I believe I am accurate.

  9. #8
    marklt is offline Cadillac Owners Member
    Automobile(s): 1976 seville
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    Re: 1979 Seville fuel injection?

    Hey Zachary, how'd that guitar pot deal work out?

  10. #9
    Zachary Smith is offline Cadillac Owners Member
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    Re: 1979 Seville fuel injection?

    I found a good used one for the coolant sensor, however a three or four position switch would be as good. One for real cold winter start, two for 30-40 degree start, three for 80 degree, and four for normal operating temp or 180 degrees. each just needs the appropriate resistor wired in. I currently have the manifold air temp on a guitar pot under the hood set around 1000 ohms. I has run very well at that setting. You can richen it or lean it out to find a happy median.

  11. #10
    Dmobe is offline Cadillac Owners Member
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    Re: 1979 Seville fuel injection?

    wcwalker,
    Make sure that your fuel pump itself is not putting out more than the required amount of fuel by the GPH rating on the pump

  12. #11
    Submariner409's Avatar
    Submariner409 is offline If it won't run, install a sound system
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    Re: 1979 Seville fuel injection?

    wcwalker has not been here for 9.5 years.

    His engine has a Fuel Pressure Regulator that cycles excess fuel back to the tank - ALL these FI engines constantly recycle a LOT of fuel back to the tank.

    PLEASE stop dredging up old, dead threads. Thanks.

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