[tech] Help diagnosing an 8V?

[soltwede@privateI.com (Night Shadow)]

> But I do have A/C, and therefore an ISV, right?  Or is this a different
> critter than the CIS-E ISV?

You have a vavle that will increase idle when the A/C is turned on, but it
is a different beast from the CIS-E ISV.

> > Michael, when you hear the car run rough, does the buzzing of the
> > frequency valve change?  Sounds like the system is adjusting the mixture,
> 
> Dunno, that's a good question.  I'll give it a listen after work tonight.

That will tell us for sure if the Jetronic brain is trying to adjust the
mixture.

> Hm.  That would be unfortunate, since this oxygen sensor has only been on my
> car since March (along with the new TT exhaust & downpipe)...

The other possibility is that your air flow plate has moved, auto-x is
alot of "on-off-on" on the throttle...could have freed up a sticking
airflow plate and you need to re-adjust it....dunno...we really need to
check what the Jetronic brain is doing (leaning the mixture too much is
what I suspect).

> > bad.  Try hitting the full throttle switch while it is idling, let us know
> > how the engine acts when you do that.
> 
> Will do.

Try it when it is acting both ways.  When it starts to stumble, hit the
switch.  If my hunch is right, the motor will smooth back out within a
second, if I am wrong, the motor will stall.  (Full throttle switch
bypasses the oxygen sensor input and puts the computer in "full rich"
mode).

--
Eric
Northglenn, CO

76 Honda CB400F Super Sport (400cc, 4 cyl, OHC 8v, 10k RPM redline *grin*)
80 Scirocco (FOR SALE $500) 
81 Scirocco S (2.0 16v swap and complete restoration in holding pattern)
81 Rabbit Truck LX Diesel (Waiting for BAE Turbo Install) 
87 Suzuki Samurai JX Hardtop (Soon to be VW Turbo Diesel Powered)
91 Cabriolet (2.0 Crossflow 8v swap and mechanical rebuild in progress) 

"For Aquarians, the physics of loopholes is a perfectly valid science."
-Kelli Fox