I had something happen to my 87 16V Scirocco that has me stumped. I
pulled out in front of a truck (a little too close) and wound it out in
the first three gears, It was at third gear doing 7,000 rpm that my
engine almost died, seemed to start running on two cylinders, and an
absolutely huge cloud of smoke erupted out the tail pipe. It was so
thick that the truck stopped, fearing a dead car in the middle of it all.
I just knew I had blown it up, but in a face saving effort, kept on
going. It gradually cleared up, and was running just fine in a mile or
so. Funny thing is, that was 6 months ago, and it’s still just fine,
with excellent compression. I used to be a VW mechanic at a dealership,
specializing in rebuilding engines,and am now a mechanical engineer who
at least thinks he knows about such things, and I have absolutely no idea
what could have caused this behavior. Any ideas from the gurus?
Mark
grif…@traveller.com
In article <4a88o2$…@tsunami.traveller.com> grif…@traveller.com (Mark Langford) writes:
>From: grif…@traveller.com (Mark Langford)
>Subject: 16V super smoker…any expert opinions?
>Date: 8 Dec 1995 02:43:14 GMT
>I had something happen to my 87 16V Scirocco that has me stumped. I
>pulled out in front of a truck (a little too close) and wound it out in
>the first three gears, It was at third gear doing 7,000 rpm that my
>engine almost died, seemed to start running on two cylinders, and an
>absolutely huge cloud of smoke erupted out the tail pipe. It was so
The engine almost dying at 7,000 RPM is probably because you hit the
rev limiter. The Scirocco is electronically limited at ~7200 RPM. The
knock control unit controls this, and I think it does it solely through
cutting the spark to the engine. If this were the case, you would have
a situation where the throttle body is wide open causing the air flow
sensor to continue dumping fuel into an engine with no spark, then
when it cut back on there would have been a flooded condition. However
you are describing a case that you believe to be caused by oil.
This explanation could be slightly far fetched, but tell me what you think.
The 16V vents the crankase by a hose on the lower front of the block instead
of the typical PVC setup. The sudden jolt from the deceleration of the
engine cutting off could have caused the oil to be feed into this tube
where it was sucked into the airbox and on into the intake manifold.
Also VW warns against overfilling the oil that it could cause damage to
the catalytic converter. With the oil sloshing around when the engine cuttoff,
this could cause similiar conditions present when the crankase is overfilled.
As far a expert opinions, this isn’t one of them.
Jim Bauer
jmba…@eos.ncsu.edu
86 16V Scirocco
My explanation, it that for a brief second you had valve float. I think
it would be fairly impossible on an OHC setup, but possibly the hydraulic
lifters pumped up, causing the valves to stick slightly open. Your lucky
no engine damage occurred, and as for the smoke, I would assume it would have
been fuel, that wasn’t burnt. This has happen to me once when, we were
checking boost on a Corrado G60. It ran on 2 cylinder for a few second,
and then was normal again.
–
John V. Cianci
1991 Jetta GTX 2.8L VR6