Throttle stuck causes engine knocks
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Cadillac Seville / Cadillac Eldorado Forum Discussion, Throttle stuck causes engine knocks in Past Cadillac Vehicle Discussion; I have an '88 Seville. Throttle got stuck after I put foot to the pedal last week and I couldn't ...
  1. #1
    kvouty is offline Cadillac Owners Member
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    Throttle stuck causes engine knocks

    I have an '88 Seville. Throttle got stuck after I put foot to the pedal last week and I couldn't get it unstuck. Finally pulled over, got under the hood and unstuck the throttle. When I started the engine, it began knocking depending on how you put your foot on the gas. It would knock a little bit then stop as the engine was idling. I was afraid I wouldn't be able to stop the car if the throttle got stuck again, so I had it towed. The tow driver said I blew the head gasket. I had my mechanic come over and listen to the knocking and he thought the rod or piston got out of whack. I was set on towing the car to a yard, cause I can't afford to have engine rebuilt. At the moment I'm second guessing myself cause when when I started it up the knocking noise went away for a few minutes then came back. Any suggestions?

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    Submariner409's Avatar
    Submariner409 is offline If it won't run, slap in a big stereo
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    Re: Throttle stuck causes engine knocks

    This question has nothing to do with Site news or registration problems. Please read the descriptive text in each forum title to find out what is supposed to be posted there.

    Moved to Seville.

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    stoveguyy is offline Cadillac Owners Connoisseur
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    Rod knock is not good. Was car your daily driver or occasional car? Am always interested when I hear of folks driving 25yr old cars. Do they use the car every day or only on weekends? You would think after 25 yrs miles would be high. Or maybe not.

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    Ranger's Avatar
    Ranger is offline Cadillac Owners Member
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    Re: Throttle stuck causes engine knocks

    I think you can safely rule out HG's. The tow truck driver had better stick to driving trucks.

    A loose rod is quite possible. How long was it stuck at WOT? I assume this knock is RPM related?

  6. #5
    amunderdog is online now Cadillac Owners Connoisseur
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    Re: Throttle stuck causes engine knocks

    http://www.carsforsale.com/used_cars...dillac_Seville
    Looks like around 1,400 for a rebuilt motor.

  7. #6
    kvouty is offline Cadillac Owners Member
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    Re: Throttle stuck causes engine knocks

    thanks everyone for comments. After starting the engine a few more times, the knocking went away. I had the throttle fixed and got some new wires, plugs and points. One wire was bad as well as a plug that had gasoline soaked into it apparently, which apparently was what caused the engine to miss. The knocking is still unaccounted for.
    Running great at the moment, but after I stopped the engine today I heard a small thud, twice - hard to describe the noise. Different from a knock , much softer, a little clunky. I went back to my mechanic who had previously told me the rod was loose & to get rid of the car. He was shocked that it was running. I'm going to get him to jack up the car and see what else might be going on next week. He thought maybe the "lifter" got stuck and unstuck? I don't know what this is, so I haven't got a clue what he means.

    In answer to the question , how long was it stuck with the throttle open about one long block til I got it stopped. And it was running at a very very high rpm. As for how often I drive, maybe once a daym not very far, I live in San Francisco so I don't have to go far. It's got 95k on the engine and after the little tuneup the engine sounds pretty good and definitely hitting on all cylinders. Could a rod go back into place after it gets loose?? I don't know if this is a dumb question, sorry.
    What kind of thug could occur after you turn off the engine completely? Probably another dumb question. But thanks for all your thoughts.

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    rodnok01's Avatar
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    Re: Throttle stuck causes engine knocks

    Not a good thunk that's for sure. What ever was knocking will rear it's head again. Drive it until it does.

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    Re: Throttle stuck causes engine knocks

    Quote Originally Posted by kvouty View Post
    He thought maybe the "lifter" got stuck and unstuck? I don't know what this is, so I haven't got a clue what he means.
    http://www.youtube.com/watch?v=lorANZ1Tptw


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    kvouty is offline Cadillac Owners Member
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    Re: Throttle stuck causes engine knocks

    thanks again. now I know what a lifter is. And I guess I will just drive it. I really appreciate all the input from everyone. I love this car and was planning on giving it to an 18 year old in a few months, who loves it too. Its just I don't know if it will last that long.

  11. #10
    kvouty is offline Cadillac Owners Member
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    Re: Throttle stuck causes engine knocks

    Same car, different problem. Have had a bit of work done since this problem above, now I have another new issue. The computer in the car keeps going off and on. It's been doing this for a long time but never went completely dead before. I thought it was because the shocks were so bad that there was a wire getting loose or something. I got the front struts replaced and the car is not bouncing anymore. However now the computer going off and on suddenly has resulted in the engine light coming on then whole dashboard going black. The engine dies too, and this makes the car unsafe unfortunately. Obviously this is some kind of electrical problem I realize. Does anyone know who works on electrical in SF Bay Area for less money than the Caddy Dealer? I've heard that the computers run upwards of $1000, I hope thats incorrect. The radio has a short in it too and I pulled the fuse awhile back.
    Any other suggestions from anyone? Thanks .

  12. #11
    STS_Seville_Hunter is online now Cadillac Owners Enthusiast
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    Re: Throttle stuck causes engine knocks

    The dash/info center goes black?
    While its on pull the the codes for the engine light, should be a sticky thread in this forum.

  13. #12
    carnut is offline Cadillac Owners Master
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    Re: Throttle stuck causes engine knocks

    Just above the gas pedal under the dash, mounted vertically is a silver box about the size of a pack of cigarettes. Its the main power supply for dash illumination. If a solder joint cracks within it, it will be intermittent or quit altogether. Remove it but leave it plugged in and dangling. Hit it with your hand while the car's running to see if the dash lights flicker on. If they do, replace it. if I recall it says constant power supply on the box. The knock noise could be your flex plate that joins the engine to your transmission. If a bolt hole cracks on it, it will knock like a rod noise. Have a trans shop pull the flywheel inspection cover and look for rust streaks ( indicates a cracked hole) on the flex plate surface. If its cracked, the trans must be removed to replace it. This constant power supply was shared with Eldo,s and Sevilles and Allante's. Ck www.allantesource.com for the newer part number that had better solder connections.

  14. #13
    kvouty is offline Cadillac Owners Member
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    Re: Throttle stuck causes engine knocks

    Thanks so much for the tip. I'm going to try this.

  15. #14
    kvouty is offline Cadillac Owners Member
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    Re: Throttle stuck causes engine knocks

    Hi Folks,
    thanks again, this forum is so helpful. I haven't pulled out the Power Supply yet, but I've found out the codes on the ECM. The error codes which are "current" are B120 and B122 which are Twilight Sentinel and Panel Lamp Dimming Circuit problems. One last code is "ECM?" - Do you think this refers to the issue of the ECM power supply itself?

  16. #15
    carnut is offline Cadillac Owners Master
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    Re: Throttle stuck causes engine knocks

    No, Its asking you if you want to display the ECM codes. Press hi fan means yes, pressing low fan means no!

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