[s-cars] Suddenly a 4 cyl S4!

[Vincent Fregeac]

Trevor,

The first step would be to rule out the ignition system. Disconnect all
injectors. Remove the cover and all plugs. Place the plugs in their
respective rubber boots. Place the cover upside down and run a non
insulated wire around each plug (on the treaded part) and attach the
wire on some grounded metal part (The coil cover is a good one). Then
start the engine. You should be able to see the plug firing from the
driver seat. If one of the plugs do not fire, swap it on another coil
and try again to determine if it's a plug or a PSO. If it's a PSO, you
can even solve your problem with no part, swapping the wires from the
defective output to the free output of one PSO. I don’t remember where
I've stored the information but if you ruled out a bad PSO, let me know
and I'll try to find the procedure.

This way, you can test your ignition at very slow speed (the starter run
much slower than idle) and with no compression, no gas, no explosion, no
heat. So, if the problem is somewhere else, there is very little chance
you make it worse.

Regarding the hard rubber boots, I would change them. If they're not
cracked yet, they will be very soon and start misfire. You can remove
them just by pulling them. You can find them at The Parts Bin
(http://catalog.thepartsbin.com/) for 20$. May be other listers can
suggest cheapest source if any. I've never deal with The Parts Bin yet
so I can't comment on the service but I've never heard bad stories about
them either.

Good luck with your diagnosis and keep us updated.



Vincent.

-----Message d'origine-----
De : s-car-list-admin at audifans.com
[mailto:s-car-list-admin at audifans.com] De la part de Trevor Topley
Envoyé : 21 mars 2003 13:58
À : audi S-cars
Objet : [s-cars] Suddenly a 4 cyl S4!

Hi Guys,
            Trevor is hoping for some quick advice.
Cruising along in traffic at 80K my 93S4 suddenly lost power and ran
real rough, smoother and boost at higher rpm but feels as if it's
dropped a cyl.
Turned around and limped home, condition stayed the same, only 20K thank
goodness.
Popped the hood and there was a "different" hot smell, most noticeable
by the turbo, even the wife noticed it when she went thro' the garage.
I have new plugs but had never taken the top off before.
Carefully lifted it up but pieces of insulator from the ends of the bake
cyls broke off, the front 2 are still flexy but the others are hard. 3
of them spin easily.
Do they come off, can you buy new ones??
I was going to pull the plugs to look for a wet one, but maybe should
fire it up again and try disconnecting injectors to identify the bad
cylinder??
I've seen other recent discussion re miss fires and "POS?"problems but
they didn't sound quite the same. This started very suddenly while the
motor was under light load, seconds before all was fine.
That's where it's sitting still, I would appreciate some advice before I
make things worse.
Thanks in advance
                         Trevor Topley
			 92/93 S4
			 90 Miata, coming out of hibernation for monday!
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