[T3] TWO Successful Repairs!!!

[Jim Adney]

TWO Successful Repairs on my old, rusty, '73 FI/AT Square

Problem #1:

Ever since I bought this car in 1990, with about 29,000 miles on it, it has had 
a problem with the second-to-third gear AT upshift. It seemed to work 
perfectly thru all other shifts, but 2-3 it slipped for a second, something 
another mechanic called "flare", which describes it pretty well, because the 
engine RPM would always spin up as the AT slipped.

So, over the last 33 years, I've looked at lots of things, trying to fix this. I 
checked the ATF level; I checked the tightness of the bands; I even pulled 
the valve body out and disassembled it, looking for bad seals or burrs on 
something. Nothing helped.

One thing I noticed about this car was that the vacuum hose to the vacuum 
modulator looped over the #1 air runner before diving down out of the 
engine and to the modulator on the AT. This seemed odd, but the hose 
appeared to be original, so I figured it was done that way at the factory, 
perhaps to creat a trap for oil, to keep it from draining down to the modulator 
end of the hose.

But William has the "same" car, and he recently confirmed that his hose 
didn't have that loop. So I replaced that hose with a shorter, more direct 
hose: no upward loop.

Now that 2-to-3 "flare" is almost completely gone. I can make it happen, just 
a bit, if I do just the wrong thing with the throttle, but most of the time there's 
no noticable flare. Problem #1 fixed, finally, after 33 years.  ;-)

Problem #2:

Within the last year, this car has started to lose "driveability." By that, I mean 
that it would start and run okay at first, but then it would get balky and finally 
I had to stop a few times and just let something cool off before it would drive 
again. It kind of felt like it was running way too rich. Last time I ran an errand 
a couple miles west of home, it took me 3 stops to get home. Totally useless!

I decided to pull out the fuel pressure regulator and drill the small vent hole 
that I've recommended for all our FI cars. That's an easy concept, but not an 
easy thing to do, simply because it's hard to get to. So I did it at the same 
time as I replaced the vacuum modulator hose, above.

Well, the driveability problem is GONE. It seems pretty clear that the 
regulator needs a vent. it's possibe that the adjuster threads were a 
sufficient vent when it was new, but it's also possible that the regulator 
diaphram has a very small leak that lets gasoline into that side, where it 
evaporates/boils and overwhelms whatever venting the adjuster threads 
provide.

I just got home from a test drive, and checked the regulator for any wetness 
there. There was none, but everything there was quite hot, so I wouldn't 
expect to find liquid gas at that temperature. I should check it again, when 
the engine is cool, but I'm not sure if that will tell me anything. It's always 
possible that it leaks more when hot than when cold. AND, it's still possible 
that there's NO gasoline leak; it may simply be that chamber heating up and 
pressurizing as the air inside expands.

And I noticed one more thing: Now, the engine dies within a few seconds 
after shutting off the fuel pump. It used to run for 10s of seconds.

Oh, and at the same time, I replaced the PCV hoses from the two cylinder 
heads. Only '72-3 have those, but the OE red hoses were rock hard and 
cracked. I used some of my yellow fuel proof Tygon; I hope that survives the 
heat. Since those hoses run under slight vacuum and have very flexible 
walls, I'll probably have to put a stretched spring inside to keep them open. I 
need to look for something like a stainless steel doorspring that's the right 
OD.

I should be able to sell kits to do this, if anyone's interested.

One final thing: While I was jacking up the car, I noticed that the plates that 
hold the rear swing arms and torsion bars in place are almost completely 
rusted out. They need to be replaced. I should have some better ones here 
somewhere. The hard part may be getting the 4 bolts out without breaking 
them.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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