[T3] Two Tests

William Jahn willjahn975 at gmail.com
Mon Sep 16 16:58:32 PDT 2019

I ran across the same thing in 2002 and this year because all I could get
were the new regulators. One issue is the base is not square with the top
so one side sits closer to the body with the vinyl . I just made a new hole
to move it out, the new one I just replaced was the same way . I put the
grounds on the rear screw with a star washer . I had the same issue on the
size of that nut forgot what size it is. I used the gen ground and test
plug ground one the rear most mounting screw. I never had an issue with it
shorting anywhere. From what I read long ago the paint on the top is not
conductive  yet I still wouldn't allow it to touch anything.

 Since you tested these 048 ECU's and the one in your car makes it rich
perhaps that's why yours works well with TS1 . If you ever find what goes
wrong in this version that can make it run rich/lean let me know.
 I'm still confused what the real difference is between the 028 and 048.
All I could find was the 028 worked with the 72 dual vacuum can yet both 72
and 73 distributors had the trigger point cam advanced. I was using a 72
dist in my car till this year when it was pinging and looks pretty rusty on
the weights yet it worked well for a good many years. Also the 73 vacuum
can does fit the 72 dist. I never had any issues with the D MPS it worked
fine and the proper one didn't really change anything.

 I noticed on the 028 it has two boards I also read that on the 72 they had
the adjustment pot for the CO Mine does not. For all I know since the tag
is missing both ECU's I have could be 048.

 All I can do is check to see in TS1 is shorted anywhere which from what I
read can cause lean running which would be pin #1 , If it is actually
shorted it might be what causes the ECU to fail in the TS1 circuit. I hope
not. I have not read of any failures because of a TS1 short in rennlist
just if it is it will be lean.  All I can do right now is check for shorts
and if I find none try the 028 to see it it changes anything as long as
it's does not have the same failure then all I can do is trace that circuit
down to see what I find in the 028.

 I also noticed when I see a high RPM 1200 and the engine is warmed up if I
tap the gas pedal a few times it will drop back down and if I see 1000 RPM
idle and push the pedal down it will raise up to 1200 so I think my cable
is sticking . I have a now one I never used . The original broke right at
the pedal years ago so I used the one from the 72 yet never greased it. If
it is this would explain the changes I see in idle speed . I did set it @
1000 hot yet if the cable sticks and I didn't make sure the throttle was
closed fully it could drop to 500 which I did see a few times. I know I set
the TPS holding the throttle closed and I recall in your TSP adjustment you
sent me to have someone press the pedal down to make sure it works at both
ends. I know I used a prop to hold the pedal down to adjust the cable which
is threaded on the end . I need to check it to know it's not sticking .
I've adjusted the idle speed a few times yet forgot to check if the
throttle was closed all the way.

On Mon, Sep 16, 2019 at 3:42 PM Jim Adney <jadney at vwtype3.org> wrote:

> This afternoon I decided to get off my butt and do 2 things that I had
> been
> postponing for way too long.
> First, I needed to replace the voltage regulator on my ratty daily driver,
> the
> beige '73 Square. I've been getting those loud clicks from the old one
> that
> always preceeds their death. Best to change it now, before any harm is
> done. This was my chance to try one of the new Bosch electronic VRs.
> I havn't been too excited about these, because they have a large upper
> shell
> which is entirely at generator output voltage. Seems like an invitation to
> shorts.
> In the process of installing this new VR, I ran across a few other
> problems
> that I think are equally troublesome.
> 1) There's no provision for attaching the ground wire. There is a pair of
> extra
> screws on top that turn out to be grounded. They're not designed or
> intended
> to be used as grounds, but that's what I did.
> 2) The stud where we're supposed to attach the D+ wire, the generator
> output, has a hex nut on top that's larger than 9 mm and smaller than 10
> mm.
> Could it be 3/8"? I don't know, but I managed to tighten it anyway.
> 3) That top shell, which is at generator output (D+) voltage is too close
> to the
> inner side wall of the body. There's a piece of vinyl there on my Square,
> but
> if that cuts thru, I'll have a short. This is all made worse by the
> "flare" at the
> bottom of the shell. I will put some thin insulator there, to keep this
> from
> happening. If I were doing it over, I'd slot the mounting holes so the VR
> could slide 1/4" farther inboard, and maybe see if I could flatten the
> flare a
> bit.
> Once installed, it seems to regulate well, but I'll need more experience
> with it
> to know better.
> The second task was to go thru my stash of FI brains and test a few '73
> 048
> brains, to make sure I had some that seemed good. I think I came up with 5.
> I pulled out the one in the car, that had been working fine for the last 3
> years, and tried each of my others in turn. Those tests were short, but my
> original '73 still seemed to run extremely rich. So I'll set that one
> aside,
> marked as bad. Apparently there is something that can go wrong with that
> version. While testing, I noticed that this last generation has 2 boards,
> an
> upper and lower. If I'd noticed that before, I'd forgotten. I'll have to
> look at
> some earlier versions to see when that started, but I don't think the ABCD
> versions were that way.
> When I was finished, I reinstalled the one that has been working well for
> the
> past 3 years.
> BTW, for those who have been following William's quest, a D pressure
> sensor was for the Euro '72s. Everything else (brain & distributor) that I
> can
> see looks to be the same as what we got here in the US.
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
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