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Dead cylinders

I have an S2 with the middle two cylinders not firing. Weird thing is the injectors are getting signal. I even swapped them out and still no luck. Plugs are sparking. Leak down is good on all cylinders and compression is 220 across the board.

Anyone have an idea?

Old 06-06-2016, 12:03 PM
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Did you try swapping the plugs. One thing I have found out is that a spark travels 10 times less distance under the compression of a cylinder than it does in the air if you pull a plug to test it.
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Old 06-06-2016, 01:28 PM
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tap the fuel injectors.... they may be sticking.
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Old 06-06-2016, 03:06 PM
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I replaced the two injectors, not much of a chance of 4 bad ones. The two I swapped out came from a car that a friend just parted out 2 months ago and was running fine
Old 06-06-2016, 04:28 PM
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Did you noid light the harness?
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Old 06-07-2016, 01:23 PM
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Quote:
Originally Posted by AZ_porschekid View Post
Did you noid light the harness?
Yes that's why I swapped injectors
Old 06-07-2016, 05:32 PM
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Have you checked the ballast resistor pack connectors? A bad connection there could give rise to the injectors not working correctly - only the 16V engines had these I believe...

The pack is located under a plate on what would be the passenger side inner wing (fender) panel.

A large aluminium pack with a round connector - mostly overlooked by people as it is pretty well hidden, but always worth a check.
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Old 06-08-2016, 02:31 PM
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Need more info.
Does the car run? when did the car last run? Does it run on 1&4 cyls? How have you confirm this? How is the speed and reference sensor gap? The wiring/connectors/sensor condition? possible arching?
I have worked on cars that have warped the flywheel, and would cause problems like this.

My best guess:

speed sensor
reference sensor
DME
engine grounds
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85 928S; LSx conversion, 5 speed with LSD.

IRR... What IRR!
Old 06-09-2016, 12:14 AM
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First, actually confirm real fuel VOLUME. Pull the rail, put little cups under each injector and crank for 10-seconds. Compare fuel-volume in each cup.

Then measure resistance of each plug wire.

Take a look inside distributor cap & rotor. I've seen brand-new caps that were strangely ovalized so two of the cylinders were getting weak spark.
Old 06-09-2016, 12:34 AM
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looks like it may be the ballast resistor

Old 06-10-2016, 12:59 PM
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