Hey there,
I have recently noticed that my car will start to misfire after it's warmed up. It only does it on idle as far as I can tell, and only for about 30 seconds. If I give it gas, it will stop immediately. I have changed the plugs, 02 sensor, cleaned the connections, etc. There is no code in the computer and my mechanic couldn't find anything. Does anyone have any ideas what could be causing this?

 

Wondering if it could be a bad ignition coil pack? Are you still using the oem one? Could be a bad wire as well. If you can figure out which cylinder the misfire is occurring in, maybe try swapping the wires to see if the misfire moves with the wire.

If you're going to try replacing the wires or ignition coil pack, use oem everything.

Wondering if it could be a fuel issue as well? Just tossing ideas out here hoping someone will expand on them.

 

The number three wire on the coil pack end is known to rust due to arching. That might be something to look at.

 

I have replaced all of the coil wires when I did the plugs, but the Coil Pack is not OEM. The PO upgraded a bunch of components including Pulley, CAI, Exhaust, Coil Pack, and maybe a tune? The coil pack is made by someone called Pilo Racing. I tried looking them up but no dice. So you think I should switch the Coil Plugs around?

 

I've never heard of that coil pack or that company, but I have not done much searching for them. I figured out pretty early that the consensus is OEM coil pack and wires is the way to go. That may be your problem, and you may want to consider switching back to the OEM coil pack.

If you can find a good deal on a used OEM pack, I'd probably give that a shot, since you don't actually know that the coil pack is bad.

I also just had a thought pop into my head that could be very wrong, but I'll say it anyway. I had a Grand Cherokee with a cooling fan that was acting up. I had suspected that it was the relay that had gone bad, and that ended up being the case. Every time I jumped the relay, the fan would turn on. But when I did not jump it, it would not turn on. It was almost like that extra shot of power made the relay open and allow the current to flow. I have yet to dive into the electrical system in this car at all, but that may be something to consider as well if its actually relevant.

What size pulley are you running and which plugs are you using?

 

interesting idea. I don't think it's revelation to my issue though. I believe the pulley is an 18% reduction. The PO installed it.

 

Common pullies are 15 and 17....some 16% around......the 19% is rare and usually troublesome.
A 15% can be pared with an overzied crank famper to get you up to a 17...so maybe a 16% and an oversized crank damper might =18%?
at idle, the bypass valve is open, so no boost...
i suggest you do a compression check....wet and dry. Might have one cylindar a bit low due to a valve or ring issue.....a good obd2 reader can get you freeze fram data, pending codes, and set codes.....the computer could be watching the misfire....a code might be comming soon.

 

If you are getting some sort of "misfire" and no codes, I would consider a solution for a problem not electrical first. Maybe not getting enough air flow at idle ?

Check air filter ? Is it a re-usable one, OEM ?

Clean inside of intercooler if not done. Use can of CRC Red Brake cleaner, then dry it out. Be sure to
re-install the rubber couplers correctly.

Drop a can of Seafoam into a full tank of gas and run it.

 

Yeah...kinda wonder if an injector is partially clogged..running one cylindar lean. A shot of injector cleaner...good stuff like bg44k, might help.

 

Thanks for the responses. The air filter is an ALTA foam CAI. I'll try looking for an oem cool pack and clean the injectors, run some seafoam through the system, and try cleaning the intercooler. How does one do the latter?

 

Don't quote me on this but I could swear I remember reading that seafoam was not the way to go with these motors.

 

Mine did the same thing. Never threw a code, didn't have the miss at anything more than idle and would go away if you tapped the throttle. My issue was shot o-rings on the fuel injectors. The o-rings on the manifold side of the #3 & 4 cylinders nearly came out in two pieces. Look closely to see if you can see where any fuel has been seeping out, if so that might be you're problem.

 

I had a misfire code on my 02' R53 and did the same thing. I replaces the ignition coil, wires and plugs, thinking it might be an ignition issue. Alas, the misfire remained. Eventually, I did a compression test and found a compression loss in cylinder 1. That was the cause of the misfire.
Now, as far as your specific case is concerned, I also had no codes for awhile and then one day the check engine light came on.
So, basically what I am saying is, do a quick compression test just to rule out the possibility of bad rings.

 

My 09 R55 starting the same problem today at 45k. Misfires at idle, jumps and lurches when in drive idleing. It throws an Orange CEL. Runs fine under acceleration though. Took it to dealer, immediately. They tested plugs, fuel rail pressure, etc. They can't seem to figure out why it's misfiring at idle....so far. Further testing to be done Monday the 24th. BTW, my warranty expired on 12/14/12.....what a coincidence!

I hope it's the HFP, as that has extended warranty on all MINIs. I do run 91 Octane, Costco most of the time and Chevron about 1/3 of the time. Never had a fuel problem issue with Costco, in 44k miles of driving; I don't expect it's bad fuel nor do I wish to start a fuel debate here.

Just looking for ideas, if anyone has been able to sucessfully solve this problem or has their dealer successfully solve it. HFP, MAF, TPS or maybe an o2 sensor...maybe?

Love! the car and my local dealership (MINI of Murray); I have a great, one of our best local techs, on the car doing the diagnosis and repair. I just hate these little (possibly expensive?) problems.

Has anyone had MINI Corporate step up and help them, especially when the warranty just barely expired? I do have the exetended service contract on my car, but not the extended warranty.

 

A quick update on misfire at idle....

MINI corporate stepped up, and covered the repairs 100%. It was simple repair, thankfully. Remove and replace the VANOS solenoid, test run car and clear all misfire faults. The car runs very well now; amazing how much havoc a failed VANOS solenoid can create! My local dealer did a great job getting the car in and out, as quickly as possible and was great in working wih MINI to get the repairs coverd by warranty. Kudos to MINI and Mini of Murray for great customer service.

 

Wrong section i take it?

 

Yes, my post should have gone to gen II MINI 2007-2010, my bad. Long day at the office....