Re: Momentary power loss

[steveb@newkla.kla.com (Steven Buchholz)]

> I just got my 875KCSTQ back from the shop.  They replaced the exhaust
> manifold, power steering pump, and fuse box. (big $$$).  During the test
> drive we encountered something new that has them stumped.
> 
> When accelerating, the engine will totally shut down for just a second at
> about 3500-4000 rpm. It kicks right back in and is smooth as the revs keep
> climbing.
> 
> It seems electrical rather than mechanical or fuel related.  Current suspect
> is the vacumn selenoid associated with the turbo (please excuse my lack of
> specificity, I'm pretty new at this)
> 
I would suspect that one of the sensors to the ECU is faulty or perhaps
your wastegate is a little sticky and causing a temporary overboost sit-
uation.  Do you notice a higher than normal boost under acceleration?  
One other thing that just came to mind ... grounding.  If the ground from
the ECU to the intake manifold is flaky the ECU can get some faulty sig-
nals and go into limp-home mode for a second.  I've never had the problem
myself with the '88 5kCSTQ, but on the '83 QTC I have had several occur-
rences of bad grounds or sensor inputs that cause the ECU to set the rev 
limit @ 4K.

HTH!
Steve Buchholz
s_buchho@kla.com