random shaking

[larsen101]

every few times i come to a stop in my truck and then give it some gas in first i get this real bas shaking and im not sure if its the engine or the tranny. its a 5spd manual and it just got a new clutch would that be it or could it be something else. ps it only happens in 1st gear nothing else and once the clutch is all the way out it is normally fine??

 

[IMenriched]

1st check for codes

throw out bearing?? clutch??
check for correct oil level in tranny?

clean the AIC (air Idle control)
check FPR (fuel pressure regulator)

 

[larsen101]

ok cool. also would a miss fire cause something like this???

 

[IMenriched]

Lots of things would cause a miss fire. That is why it is a good idea to get codes that have been tripped. To help narrow the field of choices. It might be a just a plugged fuel filter??

you may want to check out the Tech Library....(see above tab)....& dig through it maybe you'll find some useful information there.

Here is a link, (below),to the section on getting codes
http://www.therangerstation.com/tech_library/OBD_I.html

 

[larsen101]

how do i check the codes on my truck its and 87?? and never done that before

 

[Coleosis]

When my motormounts went out in my maxima, it shook when i accel'd hard...mostly during take offs or if I was on the highway over about 75mph...Do you accell in first harder than any other gear? Probably not the problem, but it wouldnt hurt to give them a look.

 

[IMenriched]

how do i check the codes on my truck its and 87?? and never done that before

AGAIN in the tech library
http://www.therangerstation.com/tech_library/OBD_I.html
__________________

 

[larsen101]

ya i dont start off hard in first so i dono about that. the shaking just happenes at randon one time i will be ok and then the next light it will shake for a second of to off the start in first??

 

[Coleosis]

Did you bleed the clutch? My car shakes when I let the clutch out too fast and dont give it enough gas. If the codes dont help, I would suggest bleeding/adjusting the clutch or running some fuel injector cleaner...Its probably because you're not getting enough fuel when you take off.

 

[Rifleman]

Did you replace the flywheel or have the original machined? it could have a slight warp and cause a bad shudder that shakes the truck as the clutch begins to grab from a stop.

 

[larsen101]

i did bleed out the clutch when i replaced it about 3 months ago. i will bleed it out and see and im going to have it taken in and have the codes checked i dont have the stuff to do that. i still have the origional fly wheel and was not machined? wouldnt that cause it to shake on all the starts or just some?

 

[Coleosis]

Just depends on how the clutch catches on that particular take off, how much gas you're giving it, how fast you're letting off the clutch....sometimes when i take off in second it shakes.

 

[Rifleman]

If you were to drop the tranny and inspect your flywheel, I would bet you could see discolored spots throughout the contact patch of the flywheel and if you didn't replace the pressure plate, it as well. The spots can be streaks, blotches, and spots, typically the size of a BIC pen or larger (see image below for example). These heat spots are a sign of guaranteed warping in the flywheel surface and/or pressure plate. Take it to any automotive machine shop and they can resurface and rebalance it. As long as any surface damage to the clutch disc or pressure plate is repaired (the PP will show the same damage as the flywheel and should be either machined or replaced at the same time as a clutch disc as well) it should cure 100% of the shuddering until you overheat the clutch repeatedly over time.

Machining both parts should be less than $50.


Example image of overheat damaged flywheel/pressure plate surface.
Needs resurfaced at autmotive machine shop or replaced.

Thanks to AllFordMustangs.com for the above image.

Image of a fresh surface

Thanks to NorthWestOffRoad.com for the above image.

***HINTS***
Touching the surfaces of the clutch disc, flywheel, or pressure plate during installation can cause hot spot damage like the first picture. All surfaces should be fully clean of any form of contaminant.

The damage naturally occurs most often when you touch the throttle two or three times as you take off, altering the RPMs of the engine up and down irratically. Some think it sounds cool, but it has consequences, overheating the clutch. If you note at the right and left of the first picture, within the contact patch for the clutch disc, you can see two hot spots that "match" each other. Those are marks from the holes in the stock clutch disc. When revving the engine multiple times during a take off, it creates added friction and heat. Then once the clutch is released, the flywheel, clutch disc, and pressure plate are all sandwiched together, not allowing the heat to escape (most likely during long hard accelerations) causing the heat defects and warping the surface.

 

[larsen101]

ok so i ran codes today and everything came up good other than then some egr which i will be fixing. so its not the engine what do you think about engine mounts? would that cause some shaking and how would i check that?

 

[larsen101]

so it ended up being the flywheel. looked real similar to that pic you put up but not that bad and had a bunch of small cracks. thanks for all the help