[T3] Getting Ready for the Gathering

[William Jahn]

I replaced my fuel regulator , mine was working but making this loud noise
and getting worse. It was a nightmare to do.

On Thu, Jun 8, 2023 at 10:10 PM <jadney at vwtype3.org> wrote:

> My '71 Square has been parked in our garage since last year's trip to
> Cincy, so last weekend
> it was time to get it out and get it ready for the Gilmore Aircooled
> Gathering in western
> Michigan.
>
> A month or so ago, I'd been driving the rusty '73 back from a friend's
> shop about 20 miles
> south of here. I was just over a mile from home when it started to buck,
> backfire, and
> generally not want to go any farther. Well, I managed to nurse it home,
> and later I discovered
> that the vacuum hose had fallen off the Pressure (MAP) Sensor. I figured
> it had just fallen off,
> so the fix was easy.
>
> Unfortunately, a couple weeks later, I drove it again for some local
> errands, and had to stop a
> few times to let it recover (cool?) so it would drive another half mile.
> Checked that same
> hose, but it was okay this time. Now I'm thinking the hose just blew off
> when the car
> backfired, but the root problem must be something else.
>
> So this got me thinking about other possibilities, and could any of them
> be things I should
> check/fix on the '71 before the trip to Michigan. I figure there are three
> possibile problems
> with the '73 that could cause these symptoms, which appear to be excessive
> richness or bad
> injection timing: FI trigger point gaps, Pressure (MAP) Sensor drifted out
> of cal, or that weird
> non-venting problem with the fuel pressure regulator that causes fuel
> over-pressure.
>
> Well, I went thru the '71 distributor last year, so I can cross that off
> the '71 list.
>
> I had a couple '71 MAP sensors here to check their calibration, so I
> pulled the sensor out of
> my '71 to check it while I was set up to do it. Well, it was running a bit
> rich, so mine got
> adjusted at the same time. Unfortunately, by the time this happened, the
> '73 was put away in
> the garage and filled with all the crap that gets stored in whatever car
> is stored there. So that
> will have to wait for another day.
>
> Finally, I decided to pull the fuel pressure regulator out of the '71 and
> drill the tiny vent hole
> that will prevent the over-pressure problem from ever happening. Drilling
> that little hole is
> easy, but getting that regulator out of the car took most of a day. In the
> end, I had to put the
> car up on jackstands unbolt the rear engine supports, and lower the engine
> a couple of
> inches. This was all due to the fact that the factory installed hose clamp
> was in such a
> position that it was unreachable from any direction with the engine fully
> in place.
>
> What an unnecessarily nasty job!!!
>
> The problem with the fuel pressure regulators is that the only vent for
> the air side of the
> internal diaphram is via the helical path around the threads of the
> adjusting bolt. After a few
> decades, corrosion seals this path and the air chamber becomes a sealed
> volume. Once that
> happens, the pressure regulator can't respond to changes in pressure due
> to altitude and it
> starts to respond to a warm engine compartment by increasing the fuel
> pressure. I wanted to
> fix this potential problem on my '71 before this trip.
>
> If you want, I can do the same mod on anyone else's regulator very
> cheaply. If you want to do
> it yourself, use a 0.051" carbide drill to make a very small, but
> reliable, hole on the bottom of
> the regulator body. Be sure to drill the hole in the AIR side of the
> regulator!
>
> If you don't touch the adjusting screw, the regulating pressure won't be
> altered.
>
> I'll do the same fix on the '73 after we get back from Michigan. I figure
> that's the most likely
> cause of it's problem, since it seems to show up only as the engine
> compartment gets hot.
>
> I'll add the regulator mod to my price list. I figure $5 would do it, or
> $10 if it needs to be
> cleaned. So most of the cost will be shipping, unless you have other
> things for me to do at
> the same time.
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
> _______________________________________________
> VWType3.Org mailing list - type3 at vwtype3.org
> To unsubscribe or change subscription options, visit:
> http://lists.vwtype3.org/listinfo.cgi/type3-vwtype3.org
> If you need more help, contact: gregm at vwtype3.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.vwtype3.org/pipermail/type3-vwtype3.org/attachments/20230609/a4b39a5d/attachment.htm>