[T3] On my 73 square

Sun Sep 15 19:57:35 PDT 2019

I suppose. Once if it ever does cool  off here I will check all the FI
wires , it's possible TS1 to the ECU pin 1 might be shorted somewhere ,
read if it is it will run lean. I can't run the engine no matter what the
temp is for more than 5 minutes with TS1 connected before it acts up. It
seems in that 5 minutes all that works is the head temp , it seems to warm
up pretty quick and TS1 has not even begun to change.    I really need to
check that wire to make certain it's not just shorted to ground it might be
crossed with another wire in the loom. The loom still has it's cover all
across the the front of the engine by the metal IAD cover . I looked at it
when I had the IAD and runners off it has all the original covering yet
some like TS1 the covering is cranked . I've had the engine out twice and
unplugged the harness from the engine and just laid it out of the way. I
marked where they all went , most all of the boots are gone now. I checked
what I could in 2009 mainly to each component I didn't check if either TS1
wire was crossed somewhere I can't see or nicked where it might short. It
has a long way to go before it reaches the ECU . All the grounds to the
case half trees run on both sides of the IAD , I fixed most of those
because some were brittle , others were not held well in the 1/4" spade
crimps . I  just have to check wire to wire on both TS1 leads not just to
ground but to all the other leads to the ECU from the engine .

  Since TS1 is not even close to warm and plugged in it causes this issue
it makes sense to me even though everything might look fine it could be
crossed with any ground to the injectors or TPS the CSV , trigger points.
All of these wires run near and all the way to the FBI.

On Sun, Sep 15, 2019 at 6:45 PM Keith Park <topnotch at nycap.rr.com> wrote:

> you really need to have a wideband on there to know what the AFR is in
> order
> to adjust the MPS anyway, otherwise you really are shooting in the dark.
>
> Keith
>
>
> -----Original Message-----
> From: type3-vwtype3.org [mailto:
> type3-vwtype3.org-bounces at lists.vwtype3.org]
> On Behalf Of Jim Adney
> Sent: Sunday, September 15, 2019 5:07 PM
> To: type3 at vwtype3.org
> Subject: Re: [T3] On my 73 square
>
> Bob,
>
> Clearly I'm aware of the long history of this. The problem, as I see it, is
> that
> it's pretty clear that this is NOT a pressure sensor problem. That's
> because
> it
> happened suddely, and it happens with different pressure sensors. I'm here
> in the midwest with the very same car, '73 AT/FI, running the same FI
> system
>
> without his symptoms.
>
> To me, it makes no sense to mess with the pressure sensor unless we're
> pretty sure it's a pressure sensor problem.
>
> Or, as Gene Berg would put it, "Don't put a Band-Aid on your elbow for a
> scrape on your knee."
>
> I understand that there are people out there who jump at the chance to
> "adjust" the pressure sensor. Those same people would probably suggest
> adjusting the brain, too, if it also had a simple, one-knob, adjustment
> somewhere.
>
> People tend to look at problems like this as one dimensional problems: You
> either need more or less of something. Unfortunately, even carbs are not
> one dimensional, with their interplay of main jets, idle jets, emulsion
> tubes,
> and throttle pumps. FI is even more complicated.
>
> I have a friend who refers to things like this as, "wandering around in a
> multi-dimensional parameter space." That may seem complicated, but it
> really puts it in a nutshell. Which are you going to adjust, U, V, W, X, Y,
> or
> Z? Any one of them can make things richer, but each has different effects,
> under different loads, and at different speeds, and their effects all
> overlap.
>
> It's possible that he needs another brain to swap in, as it's always
> possible
> that something really has gone wrong in there. That's just about the only
> thing he hasn't tried. That's an unlikely failure, but anything's possible.
>
> I thought we had it fixed when he found the bad relay, but that didn't
> help.
> It's
> possible, however, that the fix on the relay didn't last for long. There's
> also
> the fuel pump relay, and he hasn't monitored the fuel pressure while
> driving.
>
> Then there are the trigger point contacts, although those should make for
> poor operation at speed as well as at idle, which he doesn't see. Still,
> I'd
> like
> to see those get adjusted, because it's a common problem and is something
> simple I can do here, but it's not a DIY project.
>
> There are so many trivial mistakes that can happen that will make things
> bad. Daniel mixed up #21 with #12 in the trigger point connector, which
> made some brains work and others not (how could that be?) That wasn't
> found until we put the Bosch tester on it. Someone else found 2 wires
> swapped on their pressure sensor connector. That kept the engine from
> running at all, but I'm amazed that he was able to find this at all. I've
> seen
> the head sensor wire connected to the ground lug on the pressure sensor,
> and that car still ran, but poorly.
>
> So, my recommendations: try a different 048 brain, monitor the fuel
> pressure
>
> and the voltage to the fuel pump while driving, monitor the output voltage
> from the power relay while driving. Also see if the problem goes away if
> the
>
> TPS is disconnected. Then get this car to a Bosch tester and someone who
> knows how to use it. A second set of eyes is often able to pick up a
> problem.
>
> Jim
>
> On 15 Sep 2019 at 19:30, bobsnotch at aol.com wrote:
>
> > That's the thing Jim, that "miss at idle" started him down this road of
> going thru everything.
> > He's had a couple of threads about this on the Samba, chasing it. So far,
> the big consensus
> > has been to adjust the MPS, so he can at least plug in the IAD sensor.
> > The miss has been bugging him since 2016 or maybe 2017, as he can't get
> rid of it. He
> > ended up unplugging the IAD TS to help a running issue back then, after
> he
> got the correct
> > MPS on the engine (had been running a "D" unit).
> > He originally blamed it on the 10% ethanol being added, but we know
> better. That's not it.
>
>
> --
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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