94 gt motor vibration

Discussion in '1994 - 1995 Specific Tech' started by texmirage, Apr 19, 2011.

  1. Sorry about this repost.... put it in the wrong section.
    Background on me:
    Had this mustang for about 6 years. Never had to work on it cuz nothing ever broke, so I have limited knowledge about mustangs. Was into DSM's then motorcycles. Now I decided to start modding the mustang with some basic mods. .
    Back ground on the car:

    5.0 5 speed. 270k on the original motor. x pipe,flow, msd blaster. Car was running fine. The other day I go it alittle comming out of a parking lot. Car sounded like a pop out of the exhaust. Looked back and alot of black smoke, like a 18wheeler. It is not smoking or lossing water now. Any way now the motor vibrates hard under accelleration idles ruff. Plug spark is good. They look like they are burning good.

    Do these motors jump timming?

    In all honesty, it feels like something is out of balance. but not sure what to look for.

    one more thing I forgot to mention....
    if I rev it hard I hear whinning or draggin noise as the RPM's fall. it coming from right behind the curve going into the intake.
    then I ran across this on you tube
    "does it want to stutter when its first started or when u put it in the gear those are common symptoms of your idle air controller going bad"

    I Sorry for not discribing this very well. and thanks any help up front
  2. check your balancer to make sure it is good. make sure there is no rubber pushing out. i doubt the IAC would contribute to the black smoke. you could also do a compression check to make sure nothing internal went pop.
  3. Check the timing.
    If it is not where you last put it, the outer ring of the balancer spun.

    The timing chain is a possible culprit, but if they jump, it's usually enough to keep the engine from running.

    The IAC symptoms you mention are not as severe as what you describe.

    I am with killer and think your balancer ring spun.
    If so, it's time for a balancer.

    My 94 did it when I hit a bump, and began shaking the engine a bit.
    Then everytime I hit a fair size bump after that, it would spin more.
    So, sometimes it spun into balance and would run well, sometime it would spin 90* out and shake your fillings from your teeth. It just depended. Drove it like that for a month.

    Other thing you might try is clean the MAF.
    They are supposed to make nasty things happen if they get cruddy.

    I'd also like to say that the black smoke symptom is probably different than the shaking.
    My opinion would be that the pop from the exhaust and shock to the engine from the pop caused the balancer to spin. In other words: The balancer spun is not what caused the first symptom.
  4. For the original backfire that in theory caused your balancer to spin (assuming this is true)...
    That could have been caused by a bad o2 sensor.
    They say a bad o2 sensor causes the car to run rich.
    The build up of rich exhaust in the exhaust is what causes an exhaust backfire.
  5. balancer or not 270k miles is running on borrowed time. If you like your car I'd suggest you start looking for an engine replacement sooner than later. If you get a backup motor yours will probably last forever.. if you're luck is anything like mine anyway..lol
  6. My balancer came loose and even after replacement, the connecting rods imploded about a week later.
  7. thanks for all the input guys... I figure 17 years is pretty good out of a motor, and thats not to say this one is done yet.

    I think you guys have hit it dead on. As I said in the OP it seems out of balance or loose. I'll look into it tonight.

    Just to be clear(for me), you guys do mean the harmonic balancer right?
    I do have another motor at home. :) gt 40 heads,Intake, just picked up an e cam and trying to find some springs and RR. for it. Its a used motor but less then 100 on the clock. basically H/I/C with exhaust. and im done. modding it.
  8. Well that sounds like the route you should go. A nice fresh motor and you're all set!
  9. yes the harmonic balancer.
  10. turning the car over to wifey as her daily driver. I'm looking at builing a 5.0 ford splash. have a wrecked 96 5.0 explorer as a donor. :)
  11. any tricks to getting the H-balancer bolt off?
  12. You can check it on the car... reach behind and look for the rubber.... HAHA.

    if you feel rubber hanging out.... It slipped... and your timing went off... There is your vibration and backfire.
  13. i found the answer i was looking for on line.
  14. B.I.NGO !!!!!!! did a quickstart up. smooth runner. now for a test drive..
    Thanks for everything guys....
  15. If it was the balancer thats great. Check the timing again to be sure.
  16. I'll do that over the weekend. I needed to get it on the road for tomorrow. But I do think there is a timming issue. Car feels sloooooooow. I'll probably put a new t-chain set and water pump on it. it has run at the half way point for a good while.
  17. If it's been a balancer problem I'd be more worried about a warped crank.
  18. I didn't drive on it very much when it started vibrating. We'll see how it plays out. I can always put the parts on the other motor, if it breaks in a couple of weeks.
  19. When my balancer slipped, I wasn't able to change it for about a month...
    Nothing ever broke in the bottom end, this was about 2 years ago.
  20. good to here :)

    Update went ahead put a timing chain and water pump on the car. My plan was to change the T-chain but i was curious to see if the timing was off. didn't jump a tooth or anything but the chain had a TON of slack in it.PUmp seemed to be fine I just changed it cuz it was off already

    I set the timing to 14 and it was SLOOOOOOOW. did some adjusting on he test drive. car runs awesome. but still runs hot.
    thats enought for one day.