[s-cars] Still on 4 cylinders, some background.

[Robert Rossato]

I've been reading Jim's not-so-excellent adventures these past few weeks
and at this point I'm more, and more convinced that it is lifters.  

Coils tend to be a problem under boost.  Jim's problem smoothes out with
more boost.  Also, given that there was a significant change when he
changed his oil, unless that was completely coincidental - which it
still could be, it would definitely rule out anything electrical.

One thing you could try is to change your oil again to a lighter
viscosity, like a 5w30 and see what happens.  Just be sure to clean the
drain plug area really, really well and drain into a clean container so
you can reuse the 15w50 Mobil 1 you just put in.

bob

> -----Original Message-----
> From: s-car-list-bounces at audifans.com 
> [mailto:s-car-list-bounces at audifans.com] On Behalf Of chris chambers
> Sent: Tuesday, December 20, 2005 9:32 AM
> To: AUDIJIM at aol.com; s-car-list at audifans.com; 
> quattro at audifans.com; Audi5TurboTech at yahoogroups.com; 
> acna_pcc at yahoogroups.com
> Subject: Re: [s-cars] Still on 4 cylinders, some background.
> 
> 
> Jim,
> 
> Just because you have the same amount of spark on all cylinders
> doesn't mean the coil is good. I'm wondering if you have more
> than one weak Coil, before you start swapping out lifters I'd suggest
> swapping your coil pack.
> 
> Or atleast shipping it to somebody who can try it out on their car.
> 
> Based on your tests so far 'm inclined to guess failing coils.
> 
> HTH
> YMMV
> Chris
> 
> --- AUDIJIM at aol.com wrote:
> 
> > Since many of you are saying the same things, I'll let you know what
> > I've 
> > done so far.
> > 
> > New #4 coil and boot.
> > 5 new spark plugs.
> > 2 new POS.
> > I have swapped #4 fuel injector with #5, no help.
> > I replaced 5 fuel injector inserts.
> > I replaced all of the fuel injector O-rings.
> > I checked fuel injector signal at connector, good and is the same as
> > the 
> > other 4 cylinders.
> > I checked compression on cold engine, #4 was the best compression of
> > the 5 
> > cylinders.
> > I physically traced the wiring from the ignition and fuel 
> injector to
> > the 
> > ECU, every thing checked out good.
> > I swapped a known good ECU with no help.
> > I removed the fuel injector rail and inserted the injectors and
> > tested for 
> > fuel quantity and spay pattern, all injectors flowed the 
> same w/ good
> > pattern.
> > I removed the coil packs and boots, inserted spark plugs 
> and grounded
> > to 
> > engine, all 5 plugs sparked consistently to each other.
> > Spark plug condition (color and/or fuel saturation) is consistent
> > between the 
> > 5 cylinders.
> > No codes ever, unless I pull a connector from any of the fuel
> > injectors.
> > 
> > Before I pull the engine, I'm going to try one last thing that two
> > people 
> > mentioned/suggested, lifters. An oil change with a different
> > viscosity may have 
> > influenced a bad lifter to get worse, or possibly effected 
> the piston
> > rings on 
> > #4 cylinder. I'm leaning towards the lifters right now. I come from
> > the world 
> > of 10 valve turbo, and I can always hear a bad lifter on a 10v. Why
> > can I not 
> > hear any lifter noise on a 20v? With this being an unknown, I will
> > replace the 
> > lifters, valve cover gasket and do the whole timing belt water pump
> > routine. 
> > After that, I have two more options. Replace the engine, and/or
> > replace the 
> > engine and engine wiring harness. This might also account 
> for why the
> > engine 
> > feels like it smoothes out over 3000 RPM. Sometimes when it is warm
> > and running 
> > smooth, if I blip the throttle, it will run rough again and clear up
> > right 
> > away, but that was before the oil change. Now it runs rough a lot
> > longer than it 
> > used to.
> > 
> > Jim
> > ///S4cyinder
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> 
> 
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> 
> 
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