Volvo Turbo Diesel

I have a 1996 1.9 TD 440.

I have noticed recently when I have been driving quite hard that when I
remove my foot from the accelerator there seems to be a boost of power only
for a second or so. You can feel the car lurching forward. I don't know if
this is linked with the following problem but ......

I have also noticed occasionally when the car is sat at idle it is
over-revving and it takes a good couple of depressions of the accelerator to
stabilise. This can be quite embarrassing when sat next a spotty 14 year old
in his Peugeot 1.1 Turbo injection rally sport equip.

The accelerator cable seems free and moves easily on the throttle housing?
There doesn't seem to be any sort of
dump valve or idle valve.

Any help would be appreciated.

Steve

 

Hi, Steve - - -

While not familiar with your car, I've experienced an interesting diesel
problem in the past that might be related . . .

Background: I was living in the San Francisco Bay Area and experiencing
a rather lengthy commute each day. I switched from a Mazda RX-2 (Wankel
rotary) to a '78 Rabbit (Golf) 1.6L diesel banger - going from 14 mpg to
42 mpg in the process. This was right at the lead edge of a major oil
hassle that didn't much affect fuel costs, but raised hell with
availability. Thoroughly pleasant little car that I condemned to a slow
death with the installation of aircon. At that time, I was offered the
job that brought me to move here to Reno.

"The problem:" In the course of a weekly commute from a job and
apartment in Reno to the bosom of my family in California, I was hitting
the freeway hot and heavy. On two occasions, during hard runs on hot
summer days, the car just took off on its own. Cut the ignition and
accomplished nothing. Had to pull over and stop without declutching to
kill the engine. On one occasion, while at idle, the engine began a
very ragged acceleration on its own.

The fix: Not all that comfy with a diesel, so took the car to the VW
Dealer in Reno, who had that very week received a recall notice from the
factory. It seems that there was a problem, only apparent under high
temp operation, where engine oil on its way to recirculation into the
combustion process would condense and "pool" in the plenum chamber.
There was a drain, but too small. Under continued high temp operation,
this pooled oil would vaporize again and flow into the engine, which
treated it as crappy, but burnable, fuel. A simple plumbing change
solved the problem.

Suggestion: You have this possible source. You also have the
possibility of too much oil leaking in the turbo, with similar results.
So, you get to check the plenum for signs of oil collecting (hoping that
this is as far as you need go) and/or looking at the turbo as a source
in need of a rebuild.

Good luck.

bob noble
Reno, NV, USA