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Re: K24 and boost - more on WGFV

In a message dated 12/2/99 12:03:41 PM Central Standard Time, 
wallace@remdesign.com writes:

> Hmm, I'm not sure I understand that. Are you saying that it's better to
>  test the switch itself, which you can only do while the car's not
>  running, than to test that the switch is having the intended effect,
>  which you can do with the car running?
>  I tested my WOT switch with a Fluke and found that it had less than an
>  ohm of resistance, every time I closed it, and thought that I didn't
>  need a new one. But at Phil's and others' suggestion, I hooked up the
>  WGFV test light, to see if the switch was really doing its job. Sure
>  enough, the WGFV was getting cycled _most_ of the time, but sometimes
>  I'd open the throttle and got no light at all.

Ok, look at my scenario.  Customer comes into the shop with low boost 
readings, some known mods (which might have included a 2.0 spring on a real 
2.0bar chipped box).   I could plug in the LED light, go for a drive, the LED 
never lights.  Bad WOT?  Couldn't it indeed just be a too stiff spring?  
Couldn't it indeed by another sensor doing it's job?  OR, I could pull the 
car in, plug in the female/Fluke adapter to the WOT, and whack the throttle a 
bunch of times.  Looking at the above, it appears you did it once, found a 
reading and thought it was good.   A couple dozen will replicate the failure 
(I get an actual reading for each activation), it's the faster and same way 
as going for a 10minute WOT test drive (and no tickets:).  What makes a WOT 
switch fail, doesn't need a test drive to replicate, IME.

>  I replaced the switch and continued to use the test light, just to make
>  sure that that was the problem. And indeed, the WGFV always gets cycled
>  now when I hit WOT.
>  Using a WGFV light may not test _only_ the WOT switch, but I think it's
>  an excellent test of it and the rest of the wastegate control system.

Not sure at all what you mean by the "rest of the wastegate control system".  
Again, I'm not sure we really disagree here.  The LED is an excellent 
addition for the serious modder, I just don't know that many that are.  IME 
most want the mods, and want them to work, a bunch of annoying flashing 
lights isn't the object.  However, my only point is that saying that the WGFV 
LED as a 100% test of WOT function (the original post), really is not 
correct, and a rather misleading diagnostic advisory, IMO.  I don't buy it, 
neither will most of my customers.

My .02

Scott Justusson
QSHIPQ Performance Tuning
'87 5ktqwRS2 -10vt
'84 RS2URQ -20vt
'87 4Runner turbo