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Author Topic: Misfires on Cyl 1 only (checked coils, plugs, injectors, wiring)  (Read 5638 times)
lphsail21
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« on: September 30, 2017, 09:58:59 AM »

I am having random misfires that are only on cylinder 1 on one of my 1.8t's.
I've tried swapping coils, injectors, plugs, and replaced the melted wiring for the coils and injectors, but the problem does not follow to other cylinders. It happens randomly, under light load or idle, and I am able to do WOT pulls without triggering the misfire. Could this be some sort of gasket or cam/timing issue that I've never experienced?

Please let me know what you think. I will try anything. Logs attached.
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lphsail21
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« Reply #1 on: September 30, 2017, 10:02:46 AM »

Files attached. Upload wasn't working on new thread post.
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gt-innovation
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« Reply #2 on: October 02, 2017, 06:11:12 AM »

I am having random misfires that are only on cylinder 1 on one of my 1.8t's.
I've tried swapping coils, injectors, plugs, and replaced the melted wiring for the coils and injectors, but the problem does not follow to other cylinders. It happens randomly, under light load or idle, and I am able to do WOT pulls without triggering the misfire. Could this be some sort of gasket or cam/timing issue that I've never experienced?

Please let me know what you think. I will try anything. Logs attached.

1.Check compression
2.Replace the complete wiring harness from your coilpacks.
3.Change Spark plugs because you are not mentioning anything about that.
4.Timing problems would give you more DTCS than Misfire on 1st cylinder
5.Use and endoscope to check your piston surface and in general the cylinder.
6.Check if your spark plug has the same colour as the other 3.


I will assume you have problems in your cylinder head/gasket because there is some kind of crack on your head or something similar...
« Last Edit: October 03, 2017, 01:30:51 AM by gt-innovation » Logged
_nameless
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« Reply #3 on: October 02, 2017, 07:04:14 AM »

Or the injector is partly plugged or coil has failed
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Giving your mom a tuneup
TijnCU
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« Reply #4 on: October 03, 2017, 04:08:35 AM »

My bet also goes to low compression misfire, check that cilinder!
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4ringpieces
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« Reply #5 on: October 03, 2017, 06:04:01 AM »

Any tune changes before this started to occur?
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4ringpieces
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« Reply #6 on: October 03, 2017, 06:10:24 AM »

Any tune changes before this started to occur?
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lphsail21
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« Reply #7 on: October 04, 2017, 01:53:03 AM »

Any tune changes before this started to occur?

The only thing I can think of is switching to 50/50 E85 and 91oct fuel. I've tried switching the ECU back to stock, and the misfires seem slightly better, but still at least a few of them and always on cylinder 1.

I'm going to check the compression before I test anything else.

I assume if the compression is not 100% then I'm screwed and have to pull the motor apart? What is the usual point of failure if the compression is low on 1 cylinder? Valves or pistons?

EDIT- If I buy a used head from another AMB engine, would I be able to do the install in my garage or must I set my wallet on fire and bring it to a stupid shop?
« Last Edit: October 04, 2017, 01:57:34 AM by lphsail21 » Logged
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