Author Topic: Misfire on cylinder number 2  (Read 478 times)

Offline matthg40

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Misfire on cylinder number 2
« on: January 18, 2018, 12:05:53 pm »
Been having trouble with my 40 for a few months now which all started with the distributor filling with oil.since then it’s developed an annoying misfire which I have now worked out is happening in cylinder number 2.im just unsure as to what my next move is if I’m honest I’ve done a compression test it’s not great but not bad either.Any advice would be greatly appreciated

Offline ereeiz

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Re: Misfire on cylinder number 2
« Reply #1 on: January 18, 2018, 05:14:25 pm »
Have you checked the plug, lead, cap and rotor arm are alright? If it's not got issues on the other 3 cylinders then electrically all it could be is one of the above 4 parts.

Swap a plug from another cylinder and see if the misfire is still there, has moved, or is now in both.

Assuming nothings changed, swap the lead with another cylinder (remember to swap them round on the dizzy cap too). Test again.

Assuming the misfire still hasn't changed, I'd be looking at the terminal in the dizzy cap, if it's badly worn or chipped, etc it won't make a good contact as the rotor arm passes = weak spark.

What were the results for each cylinders compression?

Could it be a bent valve? Have you had issues with timing (especially since any work has been done that could point to something?

I'm assuming you're running standard ignition and not an aftermarket coil pack or something....

Offline matthg40

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Re: Misfire on cylinder number 2
« Reply #2 on: January 19, 2018, 05:53:48 am »
Every part you mentioned are new and correct genuine vw parts too.i also have checked plugs in other cylinders and problem is still with number 2 the plug is caked in oil.
As regards to compression test cylinders 1 3 and 4 are prefect but number 2 was 8% lower than the other 3 which isn’t the end of the world but it’s still lower than what it should be which still rings alarm bells

Offline matthg40

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Re: Misfire on cylinder number 2
« Reply #3 on: January 19, 2018, 01:31:03 pm »
Just a quick update cylinders 2 and 3 are at 8 bar and 1 and 3 are just over 11 and a half on the compression test

Offline ereeiz

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Re: Misfire on cylinder number 2
« Reply #4 on: January 24, 2018, 06:24:40 pm »
That's quite a difference in pressure. Oil can bypass the piston rings if they're worn.

Headgasket could be another reason, not sealing would allow fluids/gases in/out.

Worn valve stem oil seal would allow oil in but shouldn't cause a misfire unless it's so bad it's pissing oil in the cylinder.

I'm leaning towards rings though as I've seen your ads looking for a bottom end  ;)

Offline ereeiz

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Re: Misfire on cylinder number 2
« Reply #5 on: January 27, 2018, 05:48:52 pm »
For future reference (anyone searching and this comes up) it's melted pistons.