Need help on a vibration in a 81 turbo wagon - PeachParts Mercedes-Benz Forum

mbonly2 · #1 03-19-2008, 02:16 AM

I just picked up a 81 turbo wagon with 97k from the original family. I have a vibration when I press the accelerator both in park and driving. I feel it mostly in the seat and center of the car by my leg

I did a valve adjustment
Ran diesel purge through the system
Motor mounts
Inspected the flywheel and Y plate in the back (and changed the tranny while I was there.
Checked the front pulley and harmonic balancer.
Checked the timing from the crankshaft to the cam tower.
Checked the pump timing but may have done it wrong.

The previous owner says that they didn't replace anything major and I think they are being honest but not 100%

Nothing looks like it has been removed IE.. crank front pulley.

Any advice would be appreciated. I'm thinking pump again but just not sure.

karsten

mobetta · #2 03-19-2008, 03:10 AM

it's a diesel- it's supposed to shake........

rack dampner??

zeke · #3 03-19-2008, 08:17 AM

Have you checked the driveline?

Flex disks and center support bearing?
From your description it seems like it is coming from that area.

t walgamuth · #4 03-19-2008, 08:55 AM

It may be time for a compression test.

YOu probably should crack fuel lines to isolate the miss and then swap injectors to see if it follows the injector first.

Tom W

Dee8go · #5 03-19-2008, 09:32 AM

Wouldn't the motor mounts be a good thing to check about now, too?

mbonly2 · #6 03-19-2008, 09:51 AM

Thanks for the replys so far.

I forgot to add that the compression was 400+ on each cyl.
Motor mounts are new already.
The flex disc and center support wouldn't cause the vibration at a stand still.
Also its not a shake its a vibration.

Any other ideas??

mbonly2 · #7 03-19-2008, 09:55 AM

I have cracked eash injector line and it changed the way the engine ran.
Also swaped the injectors the other day and still had the result.

When I pulled the trans I started it without the trans in place and I swear it felt better. No I am doubting myself on that one. The only thing I can figure is that the trans exasterbated the problem when its in, but not sure.

vstech · #8 03-19-2008, 10:12 AM

the torque converter will load up the motor and exacerbate any vibration/power loss/balance issue the motor has, so that is not surprising.
97K is nothing on this motor. you may have a lot of soot on the crown/prechamber, try a REALLLLLLY good italian tune up.

mbonly2 · #9 03-19-2008, 10:15 AM

I hate to ask what an italian tune up is??

mbonly2 · #10 03-19-2008, 10:35 AM

After reading some other posts I realize that I replaced the rack dampner but didn't know what it was called. I am going to adjust it some more but I don't think it will help this other problem because it hasn't changed it yet when I replaced it and adjusted it. the precombustion idea sounds feasable and I think i'll try that one next unless any one has a better idea.

vstech · #11 03-19-2008, 11:57 AM

Quote:

Originally Posted by mbonly2

I hate to ask what an italian tune up is??

either climb a reallllllllly long hill, or hold the car in 2nd and floor it for as long as you can stand it... motor revvs really high, and burns off all the carbon and junk from the injectors/pistons/prechambers... has been known to really smooth out and improve the running condition of a diesel.

tobybul · #12 03-19-2008, 12:55 PM

Quote:

Originally Posted by mbonly2

Thanks for the replys so far.

I forgot to add that the compression was 400+ on each cyl.
Motor mounts are new already.
The flex disc and center support wouldn't cause the vibration at a stand still.
Also its not a shake its a vibration.

Any other ideas??

Is it in gear when your in a stand-still? Does it stop vibrating when put on neutral or park? If vibrating in gear, it may be tranny related. What is the condition of the tranny oil? Burn smell? Brownish color?

If so, try replacing tranny oil and filter.

rrgrassi · #13 03-19-2008, 01:16 PM

Engine shocks and tranny mount still good? I saw the engine mounts were changed, and no mention of the engine shocks or tranny mount.

Dee8go · #14 03-19-2008, 01:18 PM

Doh! Sorry. I missed the fact that you already changed the motor mounts.

JimFreeh · #15 03-19-2008, 03:20 PM

Quote:

Originally Posted by rrgrassi

Engine shocks and tranny mount still good? I saw the engine mounts were changed, and no mention of the engine shocks or tranny mount.

Transmission mount failure on the rear crossmember can cause a vibration, I've cured similar problems by replacing it.

Mount is often subject to lots of oil, and when it collapses, the tailshaft can come into contact with the crossmember, passing vibration through the floorboard.

Jim