[s-cars] I'm broke but my car is filthy rich (update)

[Darin Nederhoff]

Well, I've done a bit more prodding on my non-uber S4.  Pulled the plugs
and O2 sensor that had been in there since last November and they were all
dark as the night with soot on all cylinders.  When I start the car and
initially start driving things seem OK until it gets up to full operating
temp - then it starts running like horse$h!t.  Putting in clean (lightly
used) plugs and a new O2 sensor did noting.  Did a test for boost leaks and
she's as tight as can be at least up to the 18 psi I was able to put into
the system with my little compressor.  The car does still make full boost
albeit with a cloud of black smoke out the back.

Tonight I swapped in my other RS2 fuel pressure regulator and there was no
change.  I haven't been able to test the fuel pressure otherwise since the
034 fuel pressure gauge leaks no matter what I seem to do (grrr) and
honestly it's been so hot here in Minneapolis I haven't been able to bring
myself to mess with it.

This video clip shows how the car runs once it gets warm... things just get
lumpy and it stinks up the neighborhood.  I need to change my clothes after
a few minutes exposure to the overly rich exhaust.  Nasty.
http://youtu.be/ENUIXHJ5J4g

The car does have a Bosch 040 fuel pump from 034 as well as their fuel pump
wiring harness kit.  At times it has been crazy loud (
http://youtu.be/O3Tkn8VDos4 ) after longer drives.  Would fuel TANK
pressure have any potential effect on things here?  I suspect I do have a
leak brewing at the fuel tank or on a line somewhere up by the tank
connections.  Haven't been able to diagnose the location yet but I only
really noticed wetness or a drip if the tank is full or near full.
http://youtu.be/b7o3MK3Uc4I
Anyone ever replaced a tank?  How fun is it?  ;-)   (I actually have a new
tank for mine... but one thing at a time here.)

Anyhow, any other ideas gents?  ECU issue perhaps?





On Wed, Jun 27, 2012 at 6:14 PM, Paul Gailus <gailus at mindspring.com> wrote:

> Darin,
>
> The suggestions about the fuel pressure regulator and MAF connections
> sound like good things to check out.
> Just for diagnostics have you pulled the plugs to see if they look about
> the same. I'd expect all of them to be "sooty" if all of the cylinders are
> running rich. If only one plug looks darker then the injector on that
> cylinder is probably at fault.
>
> Does your added FP relay get activated through the original FP relay
> contacts? If not then the new relay won't respond to a pump shutdown from
> the ECU if it detects excess airflow through the MAF due to a boost leak.
> But if there's a boost leak then more air will flow through the MAF causing
> a rich mixture --but you already knew that :-)
>
> Regards,
> Paul
>
> ---------------
>
> Darin Nederhoff scarsgo at gmail.com
> Mon Jun 18 14:26:05 PDT 2012
>
> Previous message: [s-cars] Pikes Peak Urq Car #5 almost ready for 25th
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>
>
> --------------------------------------------------------------------------------
>
> Gents,
>
> After many years of reliable service my full RS2'd UrS4 has starting
> driving me slightly insane.  Last year it developed an issue with a
> high boost cut out problem which seemed very much like a weak coil.
> After MUCH tail chasing it came down to the one year old Bosch fuel
> pump being a bit too wimpy (the prior OEM Pierburg had worked
> beautifully up until the day it suddenly died).  Anyhow, the pump was
> replaced with the 034 Motorsports high flow unit and relay and the
> problem went away... until a few days ago.
>
> Now it is a bit like deja vu.  Car is once again sporadically running
> super rich at idle and under boost.  It sort of stumbles at idle and
> stinks up the neighborhood with fumes and smoke.  Example:
> http://www.youtube.com/watch?v=rkmTC2_RRj8&feature=g-upl
>
> Coils/boots, plugs, O2 sensor, bypass valve, intake hose and fuel pump
> all done last fall.  I also tried swapping MAFs and carefully cleaning
> my RS2 MAF last fall as well.  No change.  Tested over and over for
> boost leaks and could find anything.
>
> I've been averaging 20.7 MPG in mixed city/highway driving although I
> suspect that as of the last few days it is far worse.
>
> Anyone else ever dealt with this sort of thing?  Kind of scratching my
> head here as this car rarely stumps me.
>
> One thing I DO notice is that it tends to act up more if it is
> especially warm outside or hot & humid.  Could be coincidental....
>
>
>

-- 
Darin Nederhoff
Plymouth, MN

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