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Engine Specific Info and Questions => IDI Engine => Topic started by: Mikeyworks on January 21, 2005, 10:52:02 am

Title: Shaking my teeth loose....at idle
Post by: Mikeyworks on January 21, 2005, 10:52:02 am

My '85 Jetta TD is shaking the whole car when at idle. I think it's hitting the resonance frequency of the car and causing the whole thing to just start vibrating!!!!

Is there any way to up the idle maybe 50-100 rpm to get it to idle a little smoother?  I have done some testing with my foot and if you get it up anywhere past normal idle, it smooths out.

Any suggestions?

Mike

Title: Shaking my teeth loose....at idle
Post by: jtanguay on January 21, 2005, 11:08:56 am

you can definitely change the idle speed at the pump.  I'm not sure where.
My mechanic told me to just leave it for better fuel econo.  This car wouldn't rattle itself to death would it??? (i'm hoping not..)

Title: Shaking my teeth loose....at idle
Post by: Mikeyworks on January 21, 2005, 11:48:43 am

It won't rattle itself to death, but I am afraid it may hurt some of the 20 yr old electronics in the dash as that shakes!!!!

Mikey

Title: Shaking my teeth loose....at idle
Post by: jtanguay on January 21, 2005, 12:00:46 pm

All the electronics in my car, are the radio lol (stock hiedelberg). on another post someone changed the motor mounts, and it got rid of the rattle and worked fine.  I might try that when the weather gets better :D

Title: Shaking my teeth loose....at idle
Post by: MayorDJQ on January 21, 2005, 01:49:32 pm

You may have worn motor mounts, but adjusting the idle speed is pretty easy.

At idle, if you look at where the throttle cable attaches to the pump, you'll see a threaded rod the the throttle lever is resting against, with a lock nut.  Loosen the lock nut and twist the rod a little bit at a time so that it inceases the idle speed.  Depending on how bad the shakes are, you may only need an extra 50 or 100 RPMs, which shouldn't affect fuel mileage that much.  Once you have it at a speed that smooths out, tighten the locknut.

Title: Shaking my teeth loose....at idle
Post by: Mikeyworks on January 21, 2005, 02:57:20 pm

Thanks for the suggestion. I will try that!!!

Also, when the temp goes up again and we get rid of some of the snow (another 12-15" coming in the AM) I will check the integrity of the motor mounts.

Which ones usually go first?  I have an extra front hydraulic mount from a donor engine...so I can use that one too.

Mikey

Title: Shaking my teeth loose....at idle
Post by: lord_verminaard on January 21, 2005, 05:27:22 pm

Quick easy test- get a floor jack under the oil pan near the passenger side, and jack up the engine just a tad- like an inch or less.  Then start the car and check vibration.  If it's mostly gone, then your passenger side mount (the biggest pain in the arse) is probably due for replacement.  The only other mount that really transmits a lot of vibration is the rear one, and they dont fail as frequently.  (just a big solid chunk of rubber in a sandwitch)

Hey Mikey, how did the rear wheel bearing situation go with the Caddy?

Brendan
84 Scirocco 8v
00 Camaro L36 M49

Title: Shaking my teeth loose....at idle
Post by: Mikeyworks on January 21, 2005, 07:05:37 pm

Well, we are supposed to get about 15" of snow tomorrow, so I don't think I will be working on the car this weekend....maybe after it melts a bit!!!!

Then I will try the jack trick!!!

Quote

how did the rear wheel bearing situation go with the Caddy?

The rear wheel bearing situation was on the Jetta as the Caddy now has two engines in it...neither of which works...and is in the garage for the winter!!!!

I ended up taking an acetylene torch to the bearing to get it out and it was sooooo stuck on the stub axle that the only way to get it off was to replace the stub axle, bearings, etc.  I figured if I cut it off, I would have done more damage to the stub axle than would be safe. I now have all new stuff on the rear.

Thanks for the concern!!!

Mikey

Title: Shaking my teeth loose....at idle
Post by: lord_verminaard on January 22, 2005, 07:32:37 am

Well, bummer about the bearings.  I was lucky enough that my bearings were good, the 20 year old grease just turned into paste and they were "vacuumed" to the spindle.  I have found out why this car is so rust-free, the ENTIRE THING is coated with a nice smelley grimy layer of grease.  The transmission itself was completely BLACK when I pulled it out- not even a hint of pretty magnesium alloy to be seen.  Ech.

Good luck with the snow. We had about 8 or 9" last night, and it's still coming down.  Round two is on it's way!
http://www.intellicast.com/Local/USNationalWide.asp?loc=usa&seg=LocalWeather&prodgrp=RadarImagery&product=RadarLoop&prodnav=none

Was your garage heated?  I dont remember.  Mine is- good day to work on a greasy VW.   :roll:


Brendan
84 Scirocco 8v
00 Camaro L36 M49  <-- may as well be a unicycle in this snow...

Title: Shaking my teeth loose....at idle
Post by: Mikeyworks on January 22, 2005, 09:05:28 am

the heat comes in the form of a Kero-Sun Kerosene heater!!! Crank that puppy up and the garage is nice and warm....but the concrete is still COLD!!!!

Mikey

Title: Shaking my teeth loose....at idle
Post by: jtanguay on January 23, 2005, 10:40:04 pm

ah the wonders of heated flooring... :D