[s-cars] Re: [urq] //S4cylinder (#4 cylinder misfire)

[SpotatAshleys]

Jim
I am no expert on that particular engine, but seeing as you have ruled out
most things by testing, don't rule out faulty new components i.e. the new
coil on #4. I have gone down blind alleys in the past believing "new" meant
"working".
(my less than 2p worth!)

All the best

Keith

'87WR

----- Original Message -----
From: <AUDIJIM at aol.com>
To: <Audi5TurboTech at yahoogroups.com>; <urq at audifans.com>;
<s-car-list at audifans.com>
Sent: Friday, January 20, 2006 10:24 PM
Subject: [urq] //S4cylinder (#4 cylinder misfire)


> Today I finally performed a cylinder leak down test. My leak down tester
> reads in percentages and the percentages are further categorized as LOW.
MODERATE
> and HIGH leakage. SET pressure is 0 (zero) of course. 10-40% is LOW,
40-70% is
> MODERATE, and 70-100% is HIGH. I did the test twice because a couple
> cylinders would not let me get a good seal when I screwed the hose tester
into the
> spark plug hole. I cured this by spraying some WD-40 on the threads of the
tester
> and it then screwed in just fine. Cylinder #1 was the best on both tests,
> testing at LOW/35%. Cylinder #2 was at the low side of MODERATE/45%.
Cylinder #3
> was at the low side of MODERATE/40%. Cylinder #4 (the problem cylinder)
was at
> the low side of MODERATE/42%. Cylinder #5 was at the low side of
> MODERATE/43%. All lost pressure was through the dip stick indicating some
blow by with the
> piston rings. I squirted some oil down each cylinder and performed the
test
> again and every cylinder was then reading LOW. So I ended up doing the
test
> three times. There was no noise from the tail pipe and no bubbles or noise
> through the coolant expansion tank. I removed the hose to the throttle and
had no
> noise coming from the intake side of the head. I'm very happy with the
results
> because now I know that I do not have a mechanical engine problem with
cylinder
> #4. I can also say that I can rule out fuel, because I can use a
mechanic's
> stethoscope and hear #4 fuel injector click while it's misfiring. So I
have
> compression, and I have fuel. The only thing I have left to check is the
wiring
> from the ECU to the POS. Since all the POS's are new and the #4 coil is
new, I
> have eliminated them as a fault. I might have some wire degradation
between
> the ECU and the POS. I may run completely new wires from the ECU to the
POS and
> see what happens. I ran out of sun light today, so I will test tomorrow,
> weather permitting.
>
> Angry Jim
> ///S4cylinder
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