Need help diagnosing engine running rough

[SalvadorP]

[YOUTUBE]https://youtu.be/1UhOnEHIB6s[/YOUTUBE]
https://youtu.be/1UhOnEHIB6s

My car runs rough and vibrates a lot at idle and even more at 1500rpm. I've changed plugs, cleaned PCV, changed all filters, ran injector cleaner, etc.
The car does have a crack both on front muffler and cat, but why would it only vibrate at idle and 1500?
I'm suspecting a dirty MAF or distributor issues but i really dont know. What do you guys think?

Seems worse when it rains and today the engine cut out in the morning while idling cold.

[Laird Scooby]

You'd be surprised how much a leaky exhaust can upset the running. Get that fixed before you dive headlong into firing the parts cannon at it or anything else for that matter!

[SalvadorP]

Originally Posted by Laird Scooby

You'd be surprised how much a leaky exhaust can upset the running. Get that fixed before you dive headlong into firing the parts cannon at it or anything else for that matter!

Thx Dave.

When i plugged the holes with putty both me and my partner noticed it was vibrating less. But the putty didn't hold at all. Vibration is back but could be coincidence.

I'll do exhaust in the near future. Bit scared of not being able to undo the nuts. They look pretty stuck.

Do you think it is worth disassembling distributor cap and cleaning it? Never did it in this car.

Cheers
Salvador

[TonyS9]

Yes definately clean the distributor, these do suffer a little hesitation from oil in the distributor, even in a fairly ok running car. Usually much smoother when changing to distributorless ignition.

I can't hear anything in the video, just voice.

Stop the parts canon, start diagnsotics. Buy some spark checker lights (£20) and see if its noticeably different.

Run the car in the dark without any lights (DRLs or spark checkers) and look for glowing around the HT system.

[SalvadorP]

Originally Posted by TonyS9

Yes definately clean the distributor, these do suffer a little hesitation from oil in the distributor, even in a fairly ok running car. Usually much smoother when changing to distributorless ignition.

I can't hear anything in the video, just voice.

Stop the parts canon, start diagnsotics. Buy some spark checker lights (£20) and see if its noticeably different.

Run the car in the dark without any lights (DRLs or spark checkers) and look for glowing around the HT system.

I should have made a better video. But it vibrates a lot. I thought it was audible at 1500.

I didn't even know you could change the ignition system.

My first car, an Opel, would act up everytime it rained because humidity got into the distributor. Got progressively worse until distributor was changed

Is it easy to clean on the 940? Anything I should be mindful of? Like any part prone to break or hard to disassemble?

[360beast]

Originally Posted by SalvadorP

I should have made a better video. But it vibrates a lot. I thought it was audible at 1500.

I didn't even know you could change the ignition system.

My first car, an Opel, would act up everytime it rained because humidity got into the distributor. Got progressively worse until distributor was changed

Is it easy to clean on the 940? Anything I should be mindful of? Like any part prone to break or hard to disassemble?

Chances are the fibre washers are broken and the oil seal in the distributor has failed allowing oil in to the distributor cap area and allowing the rotor arm to move up and down.

[SalvadorP]

Originally Posted by 360beast

Chances are the fibre washers are broken and the oil seal in the distributor has failed allowing oil in to the distributor cap area and allowing the rotor arm to move up and down.

Should i buy those washers before i remove the cap to inspect it?

[360beast]

Originally Posted by SalvadorP

Should i buy those washers before i remove the cap to inspect it?

It requires a full strip down to replace them, if all you're doing is taking the cap off then you won't be able to change them

[Laird Scooby]

Originally Posted by SalvadorP

Thx Dave.

When i plugged the holes with putty both me and my partner noticed it was vibrating less. But the putty didn't hold at all. Vibration is back but could be coincidence.

I'll do exhaust in the near future. Bit scared of not being able to undo the nuts. They look pretty stuck.

Do you think it is worth disassembling distributor cap and cleaning it? Never did it in this car.

Cheers
Salvador

You've answered your own question there Salvador. Spray the nuts/bolts on the exhaust with penetrating oil daily before using the car and when you come to try and undo the various fasteners, get the engine nice and hot (wear gloves so you don't brn your hands) and use 6-sided sockets, not open-end spanners or 12-sided sockets.
Also sometimes trying to tighten while hot can help release the threads as long as immediately after trying to tighten you loosen.

The dizzy cap is probably worth doing too but do the exhaust first as you won't know if there's any improvement with the exhaust leaking like a sieve!

[SalvadorP]

Originally Posted by 360beast

It requires a full strip down to replace them, if all you're doing is taking the cap off then you won't be able to change them

Got it. Found a guide on this:
https://blog.fcpeuro.com/how-to-repl...otor-and-seals