stalling V6

[Pottree@xxxxxxx]

In a message dated 6/11/2003 7:24:41 PM Pacific Daylight Time, 
owner-alfa-digest@domain.elided writes:

> I've got a strange malfunction on my '89 Verde which, due to it's
> intermittent nature is proving rather tough to diagnose:
> 
> While driving, in gear, the car will suddenly loose power for only an
> instant, and then just as quickly restore everything back to normal.  This
> results in a big lurch of course as power fails, and then another one as it
> resumes.
> Further it happens so quickly that i actually don't know if the engine cuts
> out entirely, or if it merely drops down to idle.  Logic tells me that if it
> cut alltogether i would have to hit the starter to get the engine running
> again, which i do not, yet the tach drops down to the peg at 500 rpm, thus
> indicating an engine speed below idle??  Of course, if the issue was a
> system wide power loss, it could account for dead gauges.
> 
> In general it happens at a point where the coolant has just reached
> operating temperature, but the engine has not completely warmed up.
> 
> This cycle repeated itself 3 times this morning, on the way in to work, but
> once the engine was fully warmed up it ran just fine and showed no other
> signs of a problem.  Overall the engine is well maintained, and does not
> show any other signs of poor running or starting.
> 
> I'm hoping someone else out there has experienced the same thing at some
> point and could comment on possible causes for this behavior since i doubt i
> could get the power loss to repeat itself under testing conditions.
> 
Here at two things you could look at:

There is a water temp sensor on the Christmas tree of plumbing behind the 
radiator; without checking I think it is about at 8 o'clock.  If the spade 
connection to this sensor is corroded it won't send the right info to the computer 
and the result is temp related problems including stalling out or not starting 
when hot.

Another possibility is that there is wear or dirt or something causing a 
discontinuity in your AFM vane, which is quit delicate.  When the car moves 
forward, air passes into the front of the AFM's housing and this wind's speed causes 
the vane to blow over 5 (I think it is) contact points on a circuit board.  
This in turn sends the info to the computer which controls the fuel delivery 
rate.  If the contact is not just right, you get symptoms including mystery 
cutting out, sometimes on the straight and sometimes more likely when turning so 
that the sway of the turn makes a weak contact worse.

Of course, you should also check your fuel filter and fuel line to make sure 
you have no obstructions.  But if the car runs normally most of the time with 
occasional hiccups, I would guess 1) temp sensor connector spade is cruddy (I 
got this one from Fred di) or B) there is something fishy in your AFM's vane 
connections.

Good luck!

Charlie
LA, CA, USA

NOTICE: I may soon be in the market for a very good to excellent 95 164 of 
any trim level, and possibly even an automatic.  Leads appreciated by email!
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