followup: '81 Scirocco craps < 2800 rpm

Thanks for all the advice, in particular that from "old and brittle" Andrew,
because it looks like old and brittle is the problem.

I replaced most of the vacuum hoses and fittings 2yrs ago, but one presented
a problem: a plastic part connected via a short hose to the front of the
intake manifold. The part supplies vacuum to both the distributor and the
power brake. This part has seriously deteriorated into a crumbly substance,
and the brass tube onto which the hose that goes to the distributor attaches
has fallen out.

The problem is that this part is inserted into a formed plastic pipe that
goes to the power brake, and it appears that the insertion is intended to be
permanent. So, even if the plastic part is still available, what about the
formed pipe?

I'm thinking I should get some plastic 'rebuilder' and try to repair the
plastic part.

The short hose from the plastic part to the manifold is also deteriorated,
but that can almost certainly be replaced.

rgds,
nf

On Wed, 26 Jul 2006 03:18:41 GMT, in rec.autos.makers.vw.watercooled
(message > ), nutso
fasst > wrote:

> The problem is that this part is inserted into a formed plastic pipe that
> goes to the power brake, and it appears that the insertion is intended to be
> permanent. So, even if the plastic part is still available, what about the
> formed pipe?
>
> I'm thinking I should get some plastic 'rebuilder' and try to repair the
> plastic part.

How bad is the place where it's inserted? Maybe you can patch it: cut
downstream of the insertion, put a smaller-diameter brass or whatever
tube in, and clamp both sides of the replaced hose.

Ain't old cars a joy?

A

"Andrew Sullivan" > wrote in message
s.org...
> How bad is the place where it's inserted? Maybe you can patch it: cut
> downstream of the insertion, put a smaller-diameter brass or whatever
> tube in, and clamp both sides of the replaced hose.

I did a fix using Seal-All and it seems there are no leaks. Unfortunately,
this was not the major problem.

The situation prior to the repair had gotten worse, and this fix made no
difference. Now the engine won't idle, and moderate throttle just produces
spits and puffs. Engine won't go above about 1K rpm (can't get the revs up
to where it smoothed out before).

I have been checking other things. I found that the fuel return hose and
another looping hose on the fuel distributor are badly cracked, but there is
no sign of leakage.

The strangest thing I found is that the CO adjustment screw seems to have
disappeared! The plug in the hole over the screw was lost long ago, and I
could look down through the hole and see the allen screw for adjustment. Now
I look down the hole and see a flat surface - no screw head, no threaded
hole!

> Ain't old cars a joy?

For parts sellers, you bet!

nf

On Thu, 27 Jul 2006 19:34:27 GMT, in rec.autos.makers.vw.watercooled
(message > ), nutso
fasst > wrote:

> The situation prior to the repair had gotten worse, and this fix made no
> difference. Now the engine won't idle, and moderate throttle just produces
> spits and puffs. Engine won't go above about 1K rpm (can't get the revs up
> to where it smoothed out before).

You did check the timing already, right? That sure sounds like a
timing issue.

I once had the hold-down clamp bolt on the distributor come loose, and
the engine's timing went all to hell (as one can imagine). So even if
you haven't jumped a cog, don't rule out timing.

> I have been checking other things. I found that the fuel return hose and
> another looping hose on the fuel distributor are badly cracked, but there is
> no sign of leakage.

It's very unlikely to be fuel: you'd smell it if there were a leak.

> The strangest thing I found is that the CO adjustment screw seems to have
> disappeared! The plug in the hole over the screw was lost long ago, and I
> could look down through the hole and see the allen screw for adjustment. Now
> I look down the hole and see a flat surface - no screw head, no threaded
> hole!

I really can't believe it's gone; more likely some crud got in there
and plugged the hex hole. But if it _is_ gone, then you have a leak,
because that screw goes into the fuel distributor IIRC. (Don't quote
me. I don't even have one of those cars any more, so I sure don't have
the manual.)

A

You know, I once ran out of gas in a Mk1 Jetta. The spark plugs were
completely soaked with gasoline from repeated starting efforts. I had
to pull out the spark plugs and dry them with a lighter to get the car
to start and run well again.

Just a thought.

Good luck!
Maxine


nutso fasst wrote:
> Thanks for all the advice, in particular that from "old and brittle" Andrew,
> because it looks like old and brittle is the problem.
>
> I replaced most of the vacuum hoses and fittings 2yrs ago, but one presented
> a problem: a plastic part connected via a short hose to the front of the
> intake manifold. The part supplies vacuum to both the distributor and the
> power brake. This part has seriously deteriorated into a crumbly substance,
> and the brass tube onto which the hose that goes to the distributor attaches
> has fallen out.
>
> The problem is that this part is inserted into a formed plastic pipe that
> goes to the power brake, and it appears that the insertion is intended to be
> permanent. So, even if the plastic part is still available, what about the
> formed pipe?
>
> I'm thinking I should get some plastic 'rebuilder' and try to repair the
> plastic part.
>
> The short hose from the plastic part to the manifold is also deteriorated,
> but that can almost certainly be replaced.
>
> rgds,
> nf

Thanks for suggestions.

Here is the sequence of events:

Wife was driving home. About 7 blocks away the car suddenly started running
jerkily. Wife managed to get it home and into the driveway. She told me of
the problem and I went to check it out. The car started right up. I backed
out of the drive and started down the street. Car ran fine for about a
block, then started running jerkily. If I accelerated above 3K rpm
everything smoothed out. I got home and left the car sit for a while. I
looked for obvious problems, then tried starting again. Car ran as before, I
was able to get rpms above 3K and engine ran smooth. Left it sit again.
Tried to start engine to check timing. This time engine would not idle, and
would not get above about 1K rpm or so. I discovered vacuum leak, fixed it.
No change in the way the engine runs.

Spark plugs lightly carboned, brush em off with a toothbrush and they look
nearly new.

OK, problem sounds like it could be timing. But engine was timed 2 years and
about 5K miles ago. Distributor is clamped tight, cap and rotor near new, no
sign of arcing. And if it was timing, how come it briefly ran good for a
short period, and why did it smooth out at 3K?

Fuel level is very low and - given how few miles it's driven these days - I
wondered if gas was bad and there was water in the tank. But in that case I
don't think there would be carbon on the plugs.

Engine has > 250K miles, but now gets < 5K per year in short trips. Timing
belt was replaced about 40K miles ago (or at least it was supposed to be
replaced).

nf