[T3] Mystery Miss

[Jim Adney]

On 17 May 2016 at 9:48, Daniel Nohejl wrote:

> This is what´s making me think Sean is right and we´re going to have
> to cut open the heat shrink/sleeving so we can get better and more
> thorough access to individual wires at multiple points. Is that a bad
> idea? 

In general, I would avoid trying this, partly because I don't think 
you're likely to find anything there, and partly because if the fact, 
as you said, that it would be royal PITA to recover from.

OTOH, a second possible explanation for your problem would be 
Teflon's propensity to "cold flow" under heat and pressure. I never 
thought Teflon was a good choice here. I don't know to what extent 
this might effect the wire Joe used, but I can imagine a situation 
where 2 wires, pressed together in a bundle, could eventually squeeze 
out their insulation and short together. If this happened, it could 
be intermittent, but I'd expect it to be something that, for the 
wrong 2 wires, would bring the car to a permanent halt.

For that last reason, I doubt if this is your problem. Connections 
are always the weak point in any electrical system.

I'd also be really surprised if Joe had included a splice somewhere 
in the middle of a harness. And if he did, I think you'd be able to 
feel a lump there.

I suggest continuing to look at the crimp connectors around the area 
that you've found to be sensitive. Try to narrow it down first, then 
take apart the suspect connectors so you can visually check the 
crimps and also check each individual F connector to make sure it's 
tight on ITS mating M pin.

I don't THINK a problem with the #3 or 4 injector connectors would 
stop the engine. If all 4 cylinders are firing, you should be able to 
disconnect any one injector connector and only notice a reduction in 
the idle speed  

> I was also thinking that with the motor off we could hook the DVOM up
> to each wire at the MPS plug and to each corresponding wire at the ECU
> plug end and look for continuity. In flexing the wires, we might find
> a break in continuity in one of them and that´ll tell us which one is
> bad. Couldn't that work? 

It might, but it would take a lot of steady hands in a tight space. 
AND, it's a lot of work. At least the weather's better now.  ;-)

> I also wonder if there´s something else with connectivity....For
> example, when first connecting the female ends of our adapters for
> wires 16 and 24 to the long male connectors, we managed to wedge them
> between the connector and the plastic rather than slide them onto the
> connector. I suppose this could also be happening at the MPS¦.the
> metal connectors m?ght not be fitting correctly and t?e pins on the
> MPS are resting between one metal side of the wire end and the plastic
> connector. 

The mis-connection you've seen is common in those connectors, but I 
don't think it's possible in the MPS connector. A quick look in the 
end of the connector would make this obvious if it had been 
happening.  

> If it comes to it, what´s a good source for those small silver female
> connector ends? I´m not even sure what size they are. 3mm? 

They are locking F 1/8" spade (quick connect) pins. Keith Park bought 
1000 of them from AMP a few years ago and I have a few of his, but he 
didn't pay the extra that they wanted for the tin plating. His are 
plain brass, which should be fine.

> Also, Jim, the B brain you repaired has been running perfectly fine
> for over a week. I can now definitely send you back your B brain if
> you want it. 

Feel free to get as much test time into the repaired brain as you 
want. I sent you TWO tested B brains, which should have my check 
marks and monogram on them. I'd like at least 1 back before I leave 
for the Invasion. If you want to buy 1, in addition to the 1 I 
repaired, that's your choice.

Speaking of the Invasion, are you still planning to join the NE 
caravan and drive there with us? If so, any parts you have that you 
want to return, could be hand delivered when we meet up outside St. 
Louis, saving you some shipping and hassle. Melissa and I look 
forward to meeting the two of you, along with Sarah, John, Jill, and 
others (?).

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