[s-cars] Fault code 2113

[Mike Fitton]

The CPS will definitely throw a code and turn on the light when it has 
failed.  But I don't think the ECU uses it for anything except during 
start.  I'm only a few sips into my coffee this morning, but I'm pretty 
sure I unplugged the harness from a running engine when I was diagnosing 
that several months ago.  Didn't take it for a drive, but it had no 
apparent effect on the idle, and it threw the code right away.

Lately I've been wondering if the ECU isn't very sensitive to a failing 
oxygen sensor.  I haven't replaced mine in the almost 50k miles I've had 
the car and who knows how long it was in service before that.  I've 
never had a code for it, but I'm having trouble believing that it's 
still in spec and doing its job correctly.

You might also try an ohmmeter on the coolant temp sensor on the back of 
the head.  Should be in the low kiloohm range, rising as temp falls.  
Stick it on a warm engine and it'll go up about 1 ohm every few 
seconds.  Think SJM also has exact numbers on that somewhere.

Another thing that's been on my mind is the fuel pump.  I saw some 
interesting results on a dyno where they measured voltage at the pump 
throughout the run.  At idle it read around 13.5v, right about where it 
should, but as load and engine speed went up it dropped to like 11.5v.  
Don't think it was an Audi, but still scary stuff.  One doesn't normally 
check that voltage with a loaded engine so it's not easily diagnosed.  
I've also observed that, at least in my car, the fuel pump isn't 
energized until the key goes to start, even after replacing the fuel 
lines and I know there was no pressure in the rail.  Incidentally, 
before that my old lines had a slow leak and the engine would take a few 
more turns to start.

So many wonderful options!

-Cheers!
Mike


On 6/27/2010 8:41 PM, Wylie Bean wrote:
> Patient - 92 S4
> Have had the random "hiccup" for a few months, but not much else in the way of poor running.
> Friday, a weird hard start, which I thought was because I let go of the key too early then tried to re-start too quickly and washed the cylinder walls. Took 3 tries to start, without any wait in between, but 5+ seconds of cranking each time.
>
> Today, no hard-starting issues, but an episode of hard running (sluggish, like an O2 sensor going bad, and a check engine light (I was betting it was the O2 sensor code) twice on a 15 min ride home from the pool. Got home and pulled codes, and it's for the CPS. Didn't think that would affect a running engine but apparently it can, according to SJM's site?  Can also mean engine timing is off, which I hope not, considering it's been nearly 25K miles since the TB job, where a new crank gear was installed.
> I have a BBA CPS from Ed's GB last year, and there's a BBA CPS on there now that was installed by the PO 4 years ago.  Guess I should start making plans now to R&R that?
> Am I risking much by not doing a visual on the keyway in the crank gear?
> Wylie Bean
> TheRingmeister at triad.rr.com
> 90 cq
> 91 90q20v
> 92 UrS4
> 08 Q7 3.6
> Sent on the Sprint® Now Network from my BlackBerry®
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