8v mechanical injector testing & cleaning question

[jdbubb at verizon.net (Dan Bubb)]

The only way to test is to pull all four injectors out and pointing into containers, jumper the fuel pump and lift the metering plate. Best to measure for equal flow both at low plate lift and at full plate lift.

Both Cathy and Marc have pictures in this thread of injector testing although Cathy's are solenoid type at this point.
http://forums.vwvortex.com/zerothread?id=3322625

If the spray pattern is poor I don't think carb cleaner will do the trick. I had luck just one time cleaning any deposits from around the pintle with an exacto knife but this procedure has not worked at other times. OTOH, my POS 2.0L 16V runs pretty well and makes 126wHp with injectors with a pretty crappy spray pattern.

I doubt if your distributor diaphragm is a problem since it's not doing anything at WOT. The vacuum advance only adds advance at part throttle, but since there is virtually no vacuum in the intake manifold at WOT it's not doing anything then. 
Might help to make sure that the vacuum advance is not getting any vacuum at idle (since it's ported vacuum blocked off by the closed throttle plate) when you set the ignition timing by simply removing the vacuum hose and plugging it while setting the timing.
I know it's not intuitive, but once engine speed is above 3000 RPM or so, the engine needs LESS advance the higher the load and more advance at lower load. e.g. 45? at 30% throttle and 32? at WOT or thereabouts. 
HTH
Dan 

 From: "Foxx (in a box)" <foxxinabox@xxxxxxxxxxxxxxxx>
To: "scirocco list" <scirocco-l@xxxxxxxxxxxx>
Sent: Monday, July 09, 2007 7:42 PM
Subject: 8v mechanical injector testing & cleaning question
 
 
>   in my never ending question to find out why my '85 runs like crap, 
> especially in hot weather, i'm wondering if the injectors are going bad. 
> is there a way to test them other than yanking one out of the car while 
> it's still attached and running the fuel pump relay? also, if the spray is 
> bad, can they be cleaned simply by throwing them in a can of carb cleaner 
> or are there parts inside that will be damaged?
>   also, reading cathy's thread, i'm wondering if my vacuum diaphragm on 
> the distributor is going bad as the problem really seems to multiply at 
> WOT, stumbling like a drunk man walking down hill. any way to test this as 
> well? my bentley is buried and the list archives seem to be down for the 
> moment. thanx for any help.
>
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