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Author Topic: 1991 jetta eco diesel shaking bad  (Read 6993 times)

March 18, 2016, 09:25:15 pm

derrickd95

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1991 jetta eco diesel shaking bad
« on: March 18, 2016, 09:25:15 pm »
I just bought a 1991 eco diesel turbo jetta. 1.6 turbo with a 5 speed. Lets start with what I have done so far, so I drove it home 100 miles and the next morning the alt belt snapped. So I replaced it, everything was good. I drove to work and on the way home when idling it was shaking but I kind of expect that with a diesel. so I turn the heater on and the whole car started shaking violently like nothing i have ever experienced before, turn the heater off and it goes away. So the guy I bought it from stated that when you get on and off the accelerator the car pitches side to side which I noticed, he said it was the control arms that needed replacement and there are new ones in the trunk. So Im undecided between motor mounts or a bum injector, I can push up on the alternator with a jack handle and get a 1" to 2" movement if that helps. thank you in advance.



Reply #1March 19, 2016, 05:07:13 pm

ORCoaster

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Re: 1991 jetta eco diesel shaking bad
« Reply #1 on: March 19, 2016, 05:07:13 pm »
It sounds to me like you are rocking the engine front to back when you push up on the Alternator.  I would be looking at the front motor mount and the one back at the transmission.  I would also look at the one under the transmission and on the other side in front of the timing belt cover.  Might be time to try adjusting the transmission one or just buy all new and replace em all.

I also would try placing my foot on the accelerator and giving it a little bit of extra idle and try flipping the heater fan on high and see if that stops it for now.  A little higher idle might get you out of the shakes until your new mounts arrive.  And it is fairly cheap fix.


Reply #2March 20, 2016, 10:52:07 pm

derrickd95

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Re: 1991 jetta eco diesel shaking bad
« Reply #2 on: March 20, 2016, 10:52:07 pm »
yeah it seems like the shakes have went away on their own but the idle still get rougher with the heater on. I will start with the front motor mount and work my way around. I was hoping it wasn't an injector going bad. when I have more time I will check the injection pump timing and see where thats at. I also need to find a gauge so I can tell what my rpm's are.

Reply #3March 20, 2016, 11:51:54 pm

ORCoaster

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Re: 1991 jetta eco diesel shaking bad
« Reply #3 on: March 20, 2016, 11:51:54 pm »
A gauge to tell you what the RPM's are?????   You lost us.  Gauge as in to measure timing?  RPM's done with a Tach and unless you have one on the dash there are a few options but most are not normal clamp on type devices.  It is a diesel, which means its special in more ways than one.

Reply #4March 21, 2016, 02:01:21 pm

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #4 on: March 21, 2016, 02:01:21 pm »
yea, the so called gauge you speak of reads a mark you can make on crankshaft pulley, something like scotch brite can be 1 thing that will read to the timer, theres no spark so a common gas tach will leave you scratching your head, duh what do i do now?
there is a thread here somewhere about setting up your own crank tach set-up.

Reply #5March 21, 2016, 07:35:32 pm

derrickd95

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Re: 1991 jetta eco diesel shaking bad
« Reply #5 on: March 21, 2016, 07:35:32 pm »
i saw a tach adapter in the bently manual. I have the dial for reading the timing. I will swap out the two easier motor mounts first and report back with how everything went.

Reply #6March 23, 2016, 11:12:01 am

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #6 on: March 23, 2016, 11:12:01 am »
when i did mine (mk2) i found i have to take down oil pan, and get a couple of blocks of wood, (2x4s), and jack on either side of motor, and the trans too. i found the front mount to be the most difficult to get out/in, and the trans has 2 nuts that are hard to get to, and you have to get good torque on them using something like a 13mm open-end. dont forget, with all mounting nuts/bolts, loose(not very,), shake motor 2-3 times, and get good torque on them then.

Reply #7April 03, 2016, 10:13:47 pm

derrickd95

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Re: 1991 jetta eco diesel shaking bad
« Reply #7 on: April 03, 2016, 10:13:47 pm »
Well I installed the rear passengers side mount today, vibration quieted down. Took it for a longer drive about a hour later and the whole thing started shaking like crazy and it seems to always start while there is a load on the engine...i.e. Turning the steering wheel or the heater on high. I get the front engine mount tomorrow and hopefully it clears up the shakes for good. I hate seeing the dash shake so bad I can't read the gauges. Yes it has power steering and ac

Reply #8April 04, 2016, 09:42:15 am

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #8 on: April 04, 2016, 09:42:15 am »
try raising the idle rpm,

Reply #9April 04, 2016, 10:34:13 am

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #9 on: April 04, 2016, 10:34:13 am »
you have a kind of difficult problem there, if its not motor mounts, or idle speed being low. it could be a bad battery, or a bad alt. check batt voltage, although a load test is more definitive. batt voltage should hold steady at about 12.5v or soo,. with motor idleing all accessories off, alt voltage should read Above 13.7v up to 14.3v for a really good alternator. it could be bad wiring/or grounds, or a bad circuit(s). check battery terminals, and the red wires and then the grounds. it may be you need new/more grounding. try run a ground from trans/or motor to body, i thought it smart to run a ground from the main trans ground to alt top, then a ground from alt top to body. check also the battery terminal ground to body, should be 2 -1/2sized wires(black)to body.

Reply #10April 04, 2016, 10:35:44 am

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #10 on: April 04, 2016, 10:35:44 am »
maybe get under there and check condition of fuse box, &relay box, check for corrosion, or water damage

Reply #11April 04, 2016, 09:09:31 pm

derrickd95

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Re: 1991 jetta eco diesel shaking bad
« Reply #11 on: April 04, 2016, 09:09:31 pm »
Just cleaned up all the wiring, grounds and all and it starts noticeably better and no dash shaking vibration. I will keep everyone posted if something changes.

Reply #12April 05, 2016, 09:20:04 am

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #12 on: April 05, 2016, 09:20:04 am »
if that worked, my suggestion of running a ground wire or two. the main one is the trans/motor ground(to body), run a new 1!, i ran one from the alt top to the meaty fuel filter mount stud(clean it up). the other to run can be from the trans ground to the alt top, that also helps to ground alt. i like to use new nuts/bolts, and things like new washers. use things like electronic cleaner, w/sandpaper, to clean stuff up^. oh and also a tap/or die can help too.

Reply #13April 05, 2016, 09:34:15 am

derrickd95

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Re: 1991 jetta eco diesel shaking bad
« Reply #13 on: April 05, 2016, 09:34:15 am »
Charged the batt, it was at 75% and drove it to work today and by the time I got to work the alternator light was faintly flickering. I tested the alt last night and it was exactly on the low end of the figures you gave me. So I'm thinking I'm due for a alternator. It was nice to drive before it started doing that again.

Reply #14April 05, 2016, 10:14:10 am

air-cooled or diesel

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Re: 1991 jetta eco diesel shaking bad
« Reply #14 on: April 05, 2016, 10:14:10 am »
the bad grounding can kill an alt & battery. i prefer to shell out de extra bucks for a bosch rebuilt alt.

 

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