Gen1 start is weak and car has lost a lot of power. Please help.

Discussion in 'Gen 1 & 2 - Emergency Issues - Help & Maintenance' started by Craig, Feb 4, 2019.

  1. Craig

    Craig New Member

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    I have an 89' sho. I got it in 1990 with about 10000 miles on it. It has about 150K now. I work out of my home and am sort of local in my driving. I drive the car daily at least a little and drive easy. I'm 68 years old.

    I have 2 problems that may have been there for awhile, but have gotten worse. Problem 1 is a weak start. I turn the key and it starts weak and stutters a little in the low RPM range and then recovers to the normal tack (8900) setpoint. If I try to go before the car warms up, it will die and require that I push the accelerator to floor to start it, but it does start. When the car has warmed up, it runs OK. Problem 2 is that while it runs OK, there has been a major loss in power. The top speed is maybe 80MPH down hill with a tail wind. When I go up a hill in 4th, I can lose 10 MPH. The gas mileage is also real bad.

    Any help will be appreciated. The car is in good shape in and out. I do a little restoring about every 5 years and this is a 5th year. I'm hoping to get another 50K out of this car. Please help.

    Thanks,
    craig tussey
     
  2. Craig

    Craig New Member

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    MAF, plugs and wires, and O2 sensors are new.
     
  3. luigisho

    luigisho SHO Member

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    that's the early obvious stuff. have you checked the computer for stored codes? I would do that next, make a note of what pops up, clear them, and then run it for a bit and see if anything reappears. And you should recheck the firing order/plug wire routing to make sure there is no error. The firing order was incorrect in a manual way back if memory serves. also check the spark plugs for oil fouling if the valve covers are leaking really bad around the spark plug tubes. After that, time to look at less usual failures.
     
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  4. Craig

    Craig New Member

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    I began by looking at the codes. The code said thee MAF needed to be replaced. I haven't run diags again.
     
  5. sperold

    sperold Last to Know Supporting Member

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    Follow the advice from Luigisho.

    If the timing belt has skipped 2 teeth, you will get the dismal performance that you describe, but exhaust all the easier remedies first.
     
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  6. luigisho

    luigisho SHO Member

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    Have you also cleared the pcm codes and also cleared the adaptive tables that get stored in it? That might help. Timing and exhaust are also things to consider.
     
  7. SHOMON

    SHOMON 95 MTX Supporting Member

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    Fuel pump?
     
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  8. SHOdded

    SHOdded SHO Member Supporting Member

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    Three other common, and easily checked, problems are IAC, TPS and clogged EGR nostrils. Not even sure your car has EGR.

    But bad mileage could easily be a bad fuel regulator as well. Have not heard of leaky injectors, tho they do gum up if the car has been sitting awhile with E-blended fuel in the tank. Fuel filter could need servicing ...

    So clear codes, let new codes set, and check off the items from there.
     
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  9. luigisho

    luigisho SHO Member

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    That's true although there have been some bad injectors although rare along with failing pcm injector driver. Could be alot of things. just have to eliminate possibilities.
     
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  10. BaySHO Performance

    BaySHO Performance SHO Member

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    Starter weak: Cold start as well as hot start? Have the battery load tested, and make sure that the battery and starter connections are tight.

    Loss of power: Does the engine run rough, misfire or stumble at all? Is there a difference between gentle and strong acceleration? Is the loss of power across all revs? Might be caused by a vacuum leak somewhere, or a bad plug or wire if no codes.

    If the engine runs smoothly, but is just down on power, you might want to check for a bad catalytic converter. If one has disintegrated, a piece of cat material could have got lodged in the exhaust somewhere, causing excessive back pressure and robbing the engine of power.
     
  11. Dale Leonard

    Dale Leonard New Member

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    On my 89SHO I had the cats to come apart and it cost me power. I removed the cat pipes and cut the top of them open and gutted them and welded them back up and got my power back. Ran good till I got rid of it. Have found many 89's that have had bad cats.
     
  12. BaySHO Performance

    BaySHO Performance SHO Member

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    Problem is that cat material can get stuck in the cat back. I've used a drain snake before to locate the blockage. Had to get a muffler shop to open it up to remove it.
     
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