What are the symptoms of a timing belt off a tooth or two?

Discussion in 'Gen 1 & 2 - Engine, Exhaust, Drive Line & AC syste' started by jimtash, Dec 16, 2008.

  1. jimtash

    jimtash SHO Member

    Joined:
    Dec 18, 2001
    Messages:
    1,237
    Likes Received:
    176
    Location:
    nc
    Home Page:
    I'm asking because the motor in my '89 has this harshness and viration to it. Everything checks out fine as far as cylinder firing and such. No codes. Replaced the injectors with refurbished one's, plugs are good as are the wires.

    I installed it as a replacement motor several years back and it's nowhere near the level of the original motor in terms of smoothness. At idle, the motor literally shakes back and forth and I can feel a vibration coming from it. I have been completely baffled as to why it does it but now I'm thinking that the timing belt is off a tooth or two. What symptoms would be present if say the timing belt was installed incorrectly.

    Thanks.
     
  2. SHO_DOODmorrris

    SHO_DOODmorrris Owner & Fanatic

    Joined:
    Sep 19, 2005
    Messages:
    1,062
    Likes Received:
    110
    Location:
    Alberta
    that could be it but check your crank pully. i owuld think a bent/separating pully could cause that
     
  3. 93rev2sev

    93rev2sev SHO Member

    Joined:
    Nov 1, 2004
    Messages:
    6,459
    Likes Received:
    1,819
    Occupation:
    Network Eng.
    Location:
    Hockeytown
    Agreed. Could be timing belt. Does it run hot?
     
  4. itwonder

    itwonder SHO Member

    Joined:
    Dec 17, 2005
    Messages:
    1,679
    Likes Received:
    351
    Location:
    VA
    Set to TDC using the white notch in the edge of the crank pulley (may need to clean to find it, and don't use the orange notch by mistake) matched to the zero mark on the lower timing cover. Remove the upper timing cover and see if the dots on the front of the pulleys match the reference marks on the shield.
     
  5. jimtash

    jimtash SHO Member

    Joined:
    Dec 18, 2001
    Messages:
    1,237
    Likes Received:
    176
    Location:
    nc
    Home Page:
    It doesn't run hot but I did have to replace the radiator twice in it since installing this engine due to leaks.

    I just remember what the original engine was like. Quiet, smooth and could feel the torque. This engine is noisy, vibrates, is harsh and doesn't have the seat of the pants torque in it like the other. That's why I think the cam or crank timing is off because if it was mechanical, the engine would have self destructed a long time ago.

    Wierd thing is that I was using a larger throttle body and because the butterfly would constantly stick in it, I put the original back on. This in itself cut down on the vibrations about 50%. The rotational vibration was so bad that it would cause the steering wheel to shake.

    The only way I can describe it is the engine behaves as if it has a high performance cam in it.
     
    Last edited: Dec 17, 2008
  6. 93rev2sev

    93rev2sev SHO Member

    Joined:
    Nov 1, 2004
    Messages:
    6,459
    Likes Received:
    1,819
    Occupation:
    Network Eng.
    Location:
    Hockeytown
    have you double checked your firing order? I would.
     
  7. jimtash

    jimtash SHO Member

    Joined:
    Dec 18, 2001
    Messages:
    1,237
    Likes Received:
    176
    Location:
    nc
    Home Page:
    I've done it all. New plugs, new wires, checked the codes and nothing changed. Everything is where it's supposed to be as far as I can tell. This problem has plagued the engine from the get go.
     
  8. hawkeye18

    hawkeye18 Sorta cares

    Joined:
    May 18, 2004
    Messages:
    5,631
    Likes Received:
    2,712
    Occupation:
    Avionics Technician
    Location:
    Norfolk, VA
    no, he means the plug wire order. The Chilton manual (and the Haynes too IIRC) have the order of the plugs wrong, and will cause you to reverse 5 and 4, causing all sorts of driveability issues.
     
  9. NCTaurusSHO

    NCTaurusSHO Guest

    Joined:
    Jul 8, 2005
    Messages:
    1,243
    Likes Received:
    57
    Location:
    Elizabeth City, NC
    may be who ever installed the motor mixed up the injecor harness plugs with the one ones that go for the interior harnes plugs and the pcm harnes plugs located under the thermostat housing they can be mis matched
     
  10. jimtash

    jimtash SHO Member

    Joined:
    Dec 18, 2001
    Messages:
    1,237
    Likes Received:
    176
    Location:
    nc
    Home Page:
    Plug order is correct.

    Everything is as it should be that's visible and easy to access.

    I replaced the fuel injectors myself and the harness is correct. The car runs and drives fine. No missing at all. The engine just has this nasty vibration in it and is harsh.
     
    Last edited: Dec 17, 2008
  11. AREA 91

    AREA 91 SHO Member

    Joined:
    Jul 17, 2002
    Messages:
    5,065
    Likes Received:
    801
    Occupation:
    ecentric nut
    Location:
    Area 91
    Having the T belt off a tooth or two can cause a rough running engine. Does the engine feel like it has power up top, but is lacking down low? Or vice versa.

    Double check your timing. It's fairly easy.;)
     
  12. jimtash

    jimtash SHO Member

    Joined:
    Dec 18, 2001
    Messages:
    1,237
    Likes Received:
    176
    Location:
    nc
    Home Page:
    Power up top. When the secondaries kick in, they are un-noticable and yes, they are working.

    The old engine was totally the opposite and when the secondaries kicked in, I felt it.
     
  13. kevinspann

    kevinspann 87 Octane

    Joined:
    Sep 30, 2007
    Messages:
    2,964
    Likes Received:
    1,771
    Occupation:
    As little as possible
    Location:
    Richmond VA
    Was your timing off? My car seems the same way.
     
  14. rubydist

    rubydist SHO Member

    Joined:
    Jun 25, 2007
    Messages:
    5,067
    Likes Received:
    1,316
    Location:
    Denver
    one of the cars I bought had the rear head timing off 2 teeth (late, iirc) and it ran hot, would not pass emissions due to high nox (due to running hot) and was significantly down on power.
     

Share This Page

If you wish to help keep SHOforum running, please click the donation button below