[T3] loss of power & sputtering . need WOTG

[Dave Hall]

You've just come back from a long hot drive.

When I'd done a long drive touring Germany with my Camper, I suspected
something was wrong, as it behaved as yours .  Turning the engine over by
hand there was a hissing sound on one of the compressions, and not much
compression resistance.  It turned out to be a split exhaust valve in one
cylinder.  As the valve warmed up, the split opened more and the compression
dropped on that cylinder.

It was many years ago, and I've a feeling that when I investigated I also
found the heads cracked between the valve and plug, so replaced them (it was
a carbed engine, so no special heads needed).  I think quite a few heads are
cracked, without giving much trouble apart from plugs being awkward to get
out.


I hope it's not that, but a compression test will check that all's well, and
is probably worth doing first before pulling the FI apart.

Dave
UK VW Type 3&4 Club
===================


-----Original Message-----
From: type3-vwtype3.org-bounces at lists.vwtype3.org
[mailto:type3-vwtype3.org-bounces at lists.vwtype3.org] On Behalf Of Vern
Creamer
Sent: 28 July 2012 21:34
To: type3-vwtype3.org at lists.vwtype3.org
Subject: [T3] loss of power & sputtering . need WOTG

Not too long after I returned from the Invasion, my 72 Fastback MT FI
started stuttering, stumbling, missing once the engine got warm.  Here are
things I've tried; looking for suggestions as to what I have missed.  I am
not an accomplished mechanic by any stretch; no suggestion is too
elementary.  The car runs OK when cold but has less power than normal; when
it gets warmed up, it's a real challenge to drive at all ... barely made it
home when testing.

1.  valve adjustment and oil change 300 miles ago 2.  adjusted points gap 3.
replaced spark plugs gapped at .028" (2 of the old ones were at .040" upon
removal; all 4 were the right light tan/gray color; #4 gap full of dry,
gritty material) ... ran better after this, until it gets hot 4.  readjusted
the Throttle Position Switch 5.  cleaned out the vac line at the intake air
distributor 6.  retimed the engine following the Bentley instructions for
the 72 including idle adjustments with the vac lines plugged and then after
the timing was set and the lines replaced.
7.  tested the battery voltage at mid-range RPMs ... approximately 13.8V 8.
checked to make sure the coil is wired correctly (terminals 15 & 1) 9.
tested the coil output by holding the wire from the coil near the engine
block; spark is orange

I am due for a fuel filter replacement, which I'll do this afternoon.
The distributor was rebuilt approx. 3,000 miles ago by Jim Adney and ran
GREAT for my 2,700 mile Invasion trip at 27.5 mpg.

Some questions:

1.  What other kind of tests can I do to the coil?
2.  Fuel pump issue?
3.  Voltage Regulator replaced 13,000 miles ago, last May, with a
solid-state unit

Vern Creamer
Elkhorn, NE
72 Orange Fastback "Citrus" FI, MT
vccreamer at cox.net



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