[T3] '73 Idle Test

Jim Adney jadney at vwtype3.org
Thu Aug 29 05:30:50 PDT 2019

On 28 Aug 2019 at 18:18, William Jahn wrote:

>  I looked at the FI diagram page 19 FI section then looked at the color
> diagram . I see a difference. On the color diagram I see a black wire on
> #86 on the power relay coil to fuse 11 unfused side then to the ign coil
> which is hot all the time which might be the two black leads going back
> into the car. Then on page 19 it shows two wires off the starter into the
> same connector yet it's not hot. Seems they use that for the hot side of
> the power relay coil yet it's not hot all the time. What am I missing
> here?

The diagram on page 19 does not show the test connector wires. The 2 
wires coming off the starter on that page are from a single connector that 
attaches to solenoid terminal #50 that's hot only while starting. One of those 
wires goes to the CSV and the other is #18 to the brain.

The connector you sent me several photos of, with 2 black wires in one end 
and 1 black wire in the other end, is the wiring for the back up lights: one 
wire from the backup switch on the nose of the MT, 2 wires to the backup 
lights on each side.

The black wire coming off the ignition coil in the colored diagrams is the wire 
leading to the backup light switch. This is shown as done on MT cars; I 
believe it's slightly different on AT cars, where the backup light switch is built 
into the shift lever mechanism. At any rate, it has nothing to do with the FI.

On the colored diagrams, you'll see diagnostic wires (orange dots) #50 (hot 
while starting) and + (hot all the time) coming from the starter in '72, but only 
+ (hot all the time) in '73.  

Your other FI power wires look like they are probably fine, but it would make 
sense to check for some voltage drop across the FI main power relay.

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

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