[s-cars] Rough running - need advice what to try next?

Fred Munro munrof at sympatico.ca
Thu Sep 27 15:30:09 PDT 2007 

Hi Calvin;

The stumble was most evident coming on throttle after an upshift or when
suddenly opening the throttle to accelerate. Once past the initial stumble,
the engine seemed to pull OK. I suspect with the O2 sensor dead the mixture
wasn't quite right, resulting in a stumble on a major change in throttle
position.

Fred

-----Original Message-----
From: calvinlc at earthlink.net [mailto:calvinlc at earthlink.net]
Sent: September 27, 2007 1:55 AM
To: Fred Munro; James Murray; Vincent Frégeac; Scar
Subject: RE: [s-cars] Rough running - need advice what to try next?


Fred, was your stumble evident at WOT?  From what I know the O2 sensor isn't
supposed to come into play at WOT as the car is supposed to go open loop,
but a lot of times there are more systmes involved than what we are made to
believe.  Just wondering....
--Calvin


-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of Fred Munro
Sent: Wednesday, September 26, 2007 6:38 PM
To: James Murray; Vincent Frégeac; Scar
Subject: Re: [s-cars] Rough running - need advice what to try next?


Jamu;

Sounds a bit like the problem I had with the '97 I bought. Ran OK cold,
hesitated and bogged on acceleration when warm. Particularly noticeable
after a shift - felt like bad turbo lag. The dealer I bought it from
replaced the MAF, plugs, bypass valve to no effect. I replaced the O2 sensor
and all was well.

Fred Munro
'97 S6


-----Original Message-----
From: s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com]On Behalf Of James Murray
Sent: September 26, 2007 12:15 PM
To: Vincent Frégeac; Scar
Subject: Re: [s-cars] Rough running - need advice what to try next?


Merci Vincent! You da man...if it wasn't for great listers like you I don't
think I would have held onto this car! So it's not just about the S-Car it's
also about the S-List :-)

I won't be here this weekend either (thanks for the kind offer), as it's my
annual Salmon fishing trip, but if I haven't sorted this out by next weekend
I might just pop over for some help!

I will try replacing the POS, then the O2 sensor. I've done the coils and
the plugs already with no effect. It really seems to come on stronger once
the car has warmed up. I have my doubts it's the O2 sensor, as I tested it
cold and it was giving the right signals, but I will test it again when hot.
I hope it's not the freaking fuel pump... It wouldn't match the symptoms I'm
getting... But would love to install a Fuel Pressure gauge ala Don style
anyway...

I'll ping you next week, and maybe we can hook up!

Cheers, /Jamu.

-----Original Message-----
From: Vincent Frégeac [mailto:s.sikss at gmail.com]
Sent: Tuesday, September 25, 2007 7:17 PM
To: James Murray; 'Scar'
Subject: RE: [s-cars] Rough running - need advice what to try next?

Hi Jamu,

If it can help diagnose your problem, you're more than welcome to come home
and swap any part with my S-Bitch or my Rossato bins content. As she's
collecting dust for now (thinking of planning on working on the Fiat for the
moment but mostly lazily doing nothing), you can even leave with the part
that solve the problem until you receive the replacement. AFAIK, everything
is fine on my car beside the compression. Beside, I have some spare parts
that I'll probably never use.

IMS-BitchE, as it's heat related:
- Coils: could be but no BTDT. You can swap my entire coil cover with coils
and wires and you'll have a quick easy answer. If it's a problem, I have a
full set of known good 190KKm old coils collecting dust because I replaced
all of them 5 years ago while the problem was elsewhere. If needed, you can
pick the whole set for the price of one so you'll have backup.
- Not the O2 sensor, which is usually bad when cold (heater fried) or all
the time (sensor fried). Beside, it doesn't run rough at the beginning, it
just suck gas like a souped up SUV. I think I have a new one in Rossato bins
if you still want to try it. Just don't cut the wires so I can reuse it if
you don't need it.
- Don't know for heat vs knock sensors but shouldn't affect idle or low
acceleration, AFAIK. You can still try mine (you don't want to replace them
just in case, they're not cheap) but I have no idea how to remove them.
- POS, could be heat related but usually die without warning sign (one
cylinder missing hot and cold). Mines are both good if you need to swap them
or for a temporary fix.
- Could be Fuel Pump. If it's the fuel pump, it should be much worse when
you floor it. Fuel pressure variation vs rpm will also tell you. You can
check the very neat permanent fuel pressure gauge Don installed in 5 min. on
the S-Bitch for 20$. You can even take it out and install it on yours, I'll
just replace it with a straight barbed connection as I now know my problem
is not related to fuel pressure.
- Injector problems are not heat related AFAIK but I have a full set of low
mileage ones Rossatoing in the garage if you want to try them (10 min.
install as seen at the last S-Fest).
- MAF, no idea, but mine is clean so you can swap it if you want.

I won't be at home this weekend but I can leave the S-Bitch and garage keys
to my neighbour so you can do whatever you want to the S-Bitch with no
witness, and you don't even need to bring your own tools. Or we can meet on
Wednesday, or Thursday and pick the keys as I'll have no time to work in the
garage or on the S-Bitch until October so I can live without the keys for a
few days.

Fortunately, this week-end is warm and sunny because you'll have to work
outside, the Fiat is taking the warm covered spot inside. However, there's
one place in my driveway where you should be able to park both urS side to
side (work with Fiat and urS though the Fiat is quite narrower) for easier,
faster swaps.

HTH,



Vincent.

-----Message d'origine-----
De : s-car-list-bounces at audifans.com
[mailto:s-car-list-bounces at audifans.com] De la part de James Murray Envoyé :
25 septembre 2007 13:02 À : chris chambers; Scar Objet : Re: [s-cars] Rough
running - need advice what to try next?

I swapped out all coils with a new pack... So unless it's the wiring from
the POS or the POS itself I don't think that's the problem :-(

/J.

-----Original Message-----
From: chris chambers [mailto:fastscirocco_2000 at yahoo.com]
Sent: Tuesday, September 25, 2007 12:24 PM
To: James Murray; Scar
Subject: Re: [s-cars] Rough running - need advice what to try next?

James,

If your oxygeon sensor is old I'd replace that first.

Based on the fact that it happens after the car has warmed up makes me want
to look at the wiring to the coils. I'm picturing a crack in the wiring or a
weak coil.

Good luck

Chris


--- James Murray <james.murray at ericsson.com> wrote:

>
> Is my email getting through? I see nothing posted...
>
> /J
> > _____________________________________________
> > From: 	James Murray
> > Sent:	Monday, September 24, 2007 3:09 PM
> > To:	s-car-list at audifans.com
> > Subject:	Rough running - need advice what to try next?
> >
> > List advice needed....
> >
> > Patient: 93 UrS4
> >
> > Symptoms: Once warmed up, car runs rough, loss of power
> (hesistation
> > and slight bucking on acceleration), as if running with one less
> > cylinder or not getting fuel...no check engine light illuminated
> (but
> > have not pulled codes yet). Car seems fine when first cold,
> starting
> > up.
> >
> > Procedures attempted: Swapped out coil pack, Spark Plugs, and WGFV
> (no
> > appreciable difference). Have tried pulling injector connectors on
> > each cylinder, just makes it worse at idle.
> >
> > Next on the list of potential items to check:
> >
> > 1. Oxygen Sensor
> > 2. Knock Sensors
> > 3. POS Device
> > 4. Fuel pump
> > 5. Injectors
> > 6. MAF
> >
> > My number 1 candidate right now is the Oxygen Sensor... what is the
> > list advice?
> >
> > Cheers, /Jamu.
> _______________________________________________
> S-CAR-List mailing list
> S-CAR-List at audifans.com
> http://www.audifans.com/mailman/listinfo/s-car-list
>


Make April 15th just another day http://www.fairtax.org




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