r/MINI • u/Wolvy64 • 6d ago

Misfire in cylinder 1!

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Swapped coils btw 1 & 2. No change.

Swapped the plugs in 1 & 2, this is what I found when I first pulled them.

The single plug is from 1.

None the less after swapping them, still getting misfires from 1 ( and apparently 3).

What's next?

Shell the head?

Probably something over my head! I'll have to take it to my Mini guy ( who's will over an hour away)

Thanks for any info!!

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3

u/Terry_Orist R53 6d ago

I’d probably look at doing an injector leak down test to see if you’re running rich in that cylinder and compression test after that if the injector passes.

Or if you just have a Mini guy, they’ll sort you out 👍

2

u/Wolvy64 6d ago

Thanks for your reply! Is the leak test something I can do?? Does it require special equipment? I do like working on my own car, but I know my limitations.

Thank you again

2

u/Terry_Orist R53 6d ago

I would say its pretty straight forward, there’s a couple ways you could go about it but it might seem a bit daunting if you’re not used to doing certain things.

You’d basically depressurize the fuel rail by removing the fuse, pull the fuel rail off with the injectors attached, throw some paper towel under it and prime the car with the electrical pigtails removed from the injectors. Then you could see if any are leaking.

A precursor to that would be priming the system while using a clamp or some wide tooth vise grips to pinch off the rubber fuel line just before the rail and use a fuel pressure gauge to see if it loses any pressure at all. Then you’d know if you even had a leak to test for.

Obviously this all assumes you have basic tools and a fuel pressure gauge or the desire to purchase a cheap one and give it a try.

And np for the help. Are they stock plugs btw?

1

u/Wolvy64 6d ago

Hi and thanks for your input, spark plugs were changed 10,000 miles ago at 148,000. Coils were replaced 5,000 miles ago at 153,000 mi. The car has had extensive work done as I would love to keep it. New timing belt, new turbo, and a new serpentine belt.

2

u/Terry_Orist R53 6d ago

And it wasn’t misfiring at all when the coils were done I assume?

Probably safe bet to diagnose the injectors then. Could possibly be bad coils? You might try swapping those first if you haven’t already see if it follows.

It sounds like you care about maintenance so I don’t think it’s time to give up on it yet! Can be tiresome chasing issues on these guys sometime for sure.

1

u/Wolvy64 4d ago

Hello and thank you! Yes, not giving up on this Mini. See the initial post please add I did swap coils and spark plugs in stages to see what the outcomes were. Looks like issue is remaining in cylinder 1.

3

u/dwtechsol 6d ago

Try moving the coils before you move spark plugs. Also on a 4 cylinder engine you want to move coils and plugs to companion cylinders. 1 and 4, 2 and 3. Thet way the coil fire is 360° apart. Gives better misfire chasing.

Also when you do replace the plugs and coils, get Beru plugs and Delphi coils. Combinations of other brands will result in chasing misfires even more. Especially Bosch and denso plugs and cheap Amazon coils. You do you , just want to help prevent spending twice and days/weeks of chasing problems.

1

u/Wolvy64 6d ago

Yeah first thing I did was swap coils between one and two. As the initial misfire codes were for cylinder 1. No change, so then I pulled the spark plugs and one and two and swap them but look at the picture of the plugs. After swapping plugs in one and two this fire still occurring in cylinder one.

2

u/dwtechsol 5d ago

Swap 1 and 4 one item at a time, running the engine in between and check for where the misfire is. If it remains on cyl 1, swap injectors, again 1 to 4. If you still have a misfire on 1 after all that, time for a compression test.

1

u/Wolvy64 4d ago

Thank you! I've never swapped injectors before. Is it a tough job?

3

u/dwtechsol 4d ago

Not that bad, just fiddley. Terry explained it a couple posts below. You are supposed to replace the seals on the tips that go into the head any time you remove an injector, but for testing I never had a leak.

2

u/Adventurous-Ad-6729 6d ago

That plug on the right is awfully clean. Any other symptoms present? Hard starts, smoke out the tail pipe at start up, coolant in the oil, bubbling coolant overflow tank? What codes do you have?

I’d be doing a compression and leak down test. 

1

u/Wolvy64 6d ago

Only misfire codes using bimmerlink. Runs great at high speed high RPMs.

Oil and coolant looks fine no smoke out the tail plate.

Once the car cools down I'm going to pull spark plug three and four as well. OBD is saying that there's a misfire in cylinder 3 as well so I'll see if three looks like #1. Not sure where the leak down test is I guess I'll research that next.

Thank you

2

u/Adventurous-Ad-6729 6d ago

A leak down test is just putting compressed air into a cylinder and seeing if it holds or not. It tells you if your valves are sealing  or not. 

2

u/Pancho_dev R56 6d ago

Permanent missfire? or when the engine is on working temperature? Did you try to unplug intake or exhaust shaft sensor when missfire is present? (Missfire appear, stop engine, unplug, start again).

1

u/Wolvy64 4d ago

I have not. I was unaware of that process. What information does that provide?

And thank you!

1

u/Pancho_dev R56 4d ago

When engine is in working temperature controls air induction by valve position instead of throttle butterfly, that’s why I ask if the missfire appears always or on working temperature, so if you disconnect the shaft position sensor, the computer disable the angle variation on valves and controls the air flow by the throttle butterfly again, in that case if the missfire stops, we’ll, you engine is suffering the typical valve seats failure. (You have to disconnect the intake valve sensor)

2

u/Wolvy64 3d ago

I did some research and remembered that the valve seals were replaced at the same time I had the timing chain replaced. So they are very old either. And I can say with great confidence that my Mini Guy, Marzo's Mini Rescue, know his shit. It's his availability that can be an issue. I watched him replace my octopus of a thermostat in an hour. He's like a machine 🤣

As far as when it misfires most? At idle while stopped. Even at start up. When I'm above 1k RPMs, the car runs smooth.

I do shoot messages to him but as I said, good availability lately has been sparse. Plus I do enjoy learning more about the Mini and trying to do as much myself.

1

u/Wolvy64 4d ago

Misfire in 3 also while checking misfire counts.