[T3] [Non-DoD Source] Re: Fuel Pump relay not energizing

[Jim Adney]

On 24 Feb 2017 at 13:56, Dorough, Don CIV, NPPSC N3/PSD Pensacola 
wrote:

> Do you happen to know what color that wire is in the engine compartment
> (coming off pin 19 in the ECU). Mine is blue with a white dot tracer at
> the fuel pump relay - pin 85. But as you know, wires "magically" change
> colors sometimes when they go through connectors. 

I don't think there's any connection/color change between the dash 
and the engine compartment. The #19 wire coming from the FI harness 
will be white and I assume the wire from the relay will still be 
blue/white. 

> The power relay under the back seat clicks when the key is turned on,
> and I figured the ECU was getting power because the car does run if I
> manually energize the fuel pump relay.  

That's good news. I gather that you just jumpered the relay to get 
the pump to run, and then the engine would start. That's a good test, 
but you don't want to drive it that way, because an accident might 
sever a gas line and leave the pump running. Not good.

The inline connector back there is just 1:1 and it's the only such 
thing in that area. There's a 1:2 connector nearby, but that's for 
the backup lights; ignore it.

> If I suspect the transistor in the ECU I will ask for more info later.
>  I was an ET in the Navy with micro-miniature soldering training so I
> would be able to replace it. 

Okay, you're set on replacing the transistor, if necessary. In that 
case the only challenge will be getting the box opened and closed 
back up. That's actually the hard part.

> Thanks for explaining how the trigger points keep the fuel pump
> energized, makes perfect sense!!   None of that is explained in the
> Bently or the Clymer's.  Is there a detailed guide somewhere? 

None that I know of, but you might watch ebay for one of these 
Elfrink FI guides:

Volkswagen Fuel Injection Technical Manual
(covers 68-9 Type III only)
published by Henry Elfrink, Los Angeles, 1969

Volkswagen Fuel Injection Technical Manual, second edition
(covers VW Type IIIs only)
published by Henry Elfrink, Los Angeles, 1970

Volkswagen Fuel Injection Technical Manual, forth edition
(covers D-Jetronic VW Type IIIs, IVs, & Porsche 914/4s)
published by Henry Elfrink, Los Angeles, 1972

Note that the first edition only covers '68-9. That would be helpful, 
but any of the later editions would be better. I don't own a third 
edition, so I don't know what's different about it.

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