1.9L NA diesel engine shakes when letting off pedal quickly

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astroboy
Glow Plug
Posts: 15
Joined: Mon Jan 04, 2010 6:57 pm
Location: Sunnyvale, CA

1.9L NA diesel engine shakes when letting off pedal quickly

Post by astroboy »

If I let off the fuel quickly the engine shutters a bit driving me nuts. I don't remember it doing this in the distant past. I thought maybe the oil pressure was dropping too low. I changed the oil and filter and bought an oil pressure gage that screwed into one of the extra pressure switches on the top of the oil filter mount (there are 3 for some reason - none hooked up). The oil gage leaked a bit where it screw in, but at idle it had 14 or 16 psi and as I reved it up, it went up corresponding to the RPM and I stopped at 70 PSI (not reved up to the max. When I let off the throttle, the psi dropped to say 14 and did not budge even when it shuttered. I had the transmission worked on a few months ago, and the people who pulled it and sent it out for fixing work on Vanagons, and I would think if it was the rear motor mount on the tranny they would have said something. It was shuttering before I had the tranny worked on.

If I push the engine sideways, it does not move very much (like 1/8 inch pretty stiff). I guess I could have my wife rev it up and hold and then let off quickly while I gaze at the engine mounts. Any ideas?

Thanks for any help in advance - John
John

VW Vanagon bought new in 1982
Had 1.6L NA Diesel ~90k miles
Now has 1.9L NA Diesel ~50K miles
bscutt
Turbo Charger
Posts: 1720
Joined: Mon Mar 10, 2003 4:49 pm
Location: Springfield, VA

Re: 1.9L NA diesel engine shakes when letting off pedal quic

Post by bscutt »

Don't know much about the vans but I would suspect a CV joint or a motor mount. Check for any play in the axles.
Bob

'06 Jetta TDI
'82 Rabbit 1.6NA
Honda, 99 GMC Suburban, '41 Chevy Coupe
astroboy
Glow Plug
Posts: 15
Joined: Mon Jan 04, 2010 6:57 pm
Location: Sunnyvale, CA

Re: 1.9L NA diesel engine shakes when letting off pedal quic

Post by astroboy »

The engine is in my Vanagon. I actually repacked the CV joints a few months ago. The shuttering happens when I am not moving or moving. It is kind of shaking sideways as if I am running the engine at to low RPM for a second or two.
John

VW Vanagon bought new in 1982
Had 1.6L NA Diesel ~90k miles
Now has 1.9L NA Diesel ~50K miles
bscutt
Turbo Charger
Posts: 1720
Joined: Mon Mar 10, 2003 4:49 pm
Location: Springfield, VA

Re: 1.9L NA diesel engine shakes when letting off pedal quic

Post by bscutt »

Ok, I guess I assumed it was when decelerating in gear. Could be a number of things including a leaky injector, low compression in one cylinder, motor mounts, loose pump mounting bolts. This could be interesting to find and fix.
Bob

'06 Jetta TDI
'82 Rabbit 1.6NA
Honda, 99 GMC Suburban, '41 Chevy Coupe
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