[s-cars] No start (update) - Testing a CPS

[Stott Hare]

That isn't entirely true.  You should be able to verify a completely dead
cam position sensor without opening up anything more that the weather boot
on its electrical connector.  The sensor will have three leads: power,
ground and signal.  I believe the middle wire is the signal, possibly green
in color.  With the car chocked, transmission in neutral and ignition on
(motor not running) you should be able to back probe the signal wire while
the sensor is still plugged in.  The CPS is a hall sender, looking for a
window in the sensor cage mount to the cam sprocket.  IIRC with a working
CPS you should see 5v at the signal wire until the "open window" passes
through the CPS.  At that point the voltage should drop to near 0.  Now it
has been a while since I did this last, so I could have that backwards, with
it rising to 5v at the window.  Anyhow, with your voltmeter connected to the
back-probed signal wire, rotate the motor slowly.  If you don't see that
change in voltage you CPS is faulty (assuming you have power and ground to
the CPS connector).

This won't necessarily help you if you have an intermittent fault, but it
should identify a bad CPS.

-Stott

-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com] On Behalf Of Vincent Frégeac
Sent: Thursday, December 13, 2007 3:35 AM
To: theringmeister at triad.rr.com; s-car-list at audifans.com
Subject: Re: [s-cars] No start (update)

The cam sensor is not expensive (12$) but take some time (5-6 hours) to
install. There may be a faster way to install it since I decided to do my
T-Belt, T-Stat and coolant flush at the same time ;-)

Beside, IIRC, cam sensor usually doesn't pull any code. The only to know if
it's the problem is to replace it...and, of course, in my case, it wasn't :(



Vincent

-----Message d'origine-----
De : s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com] De la part de
theringmeister at triad.rr.com
Envoyé : 12 décembre 2007 15:41
À : s-car-list at audifans.com
Objet : [s-cars] No start (update)

finally happened to where I had to have it towed home (the 92 Ur).  Have
swapped FP relays and no change.  Jumped wire from "+" post to rear terminal
of fuse 17A per Dave F's instruction and could hear fuel in the line at the
rail, although I didn't pull the line and measure the specific volume of
fuel whilst doing so as I was home for lunch and didn't have time to delve
that far into it.  Also, pulled codes (with engine off for obvious reasons)
and got 2111 (obvious since engine was off, hopefully) and 4431 (idle air
control), which I hope is due to me pulling the plug on the ISV while trying
to start it when I was sitting awaiting a tow.  I performed the output
checks per SJM and all seemed to work fine, including the ISV.

I guess it could still be the fuel pump, but that (expensive) cam sensor is
starting to creep back into my mind, even with no code for it.


  
--
Wylie Bean
TheRingmeister at triad.rr.com
90 cq
91 90q20v sport
92 UrS4
01 allroad

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