Just did a valve job on an 09 r55 and the problems just dont seem to end. The thermostat developed a crack, and throttle body was returning a code for weak return spring. I seem to have these issues sorted out but I have a persistent misfire on #4. I have eliminated the coils, plugs and injectors as a possibility. Compression seems to be in line with the others. Leakdown is perfect. I checked the wiring from the DME to the coils and the injectors and it seems fine. I tried to test the injectors with a noid light but I can only access #4, and I'm not sure I'm testing it correctly. It was at a point where it was fine when cold and only started misfiring occasionally when the temp got to about 200F, but now it misfires all the time. I'm using Bavarian Tech diagnostics. Has anybody ever seen anything like this before? Is there anything else I can test?

 

How did you eliminate the plugs and coils?

Neil M.

 

Bought new ones and did multiple swaps.

 

In the "old days" we used to remove a spark plug wire, hold near a ground and crank the engine to see if there is a spark.
I tried this with the mini coil but the electrode is too far in. You could probably make a spark gap with a jumper cable to gnd and a screwdriver on the other end partially inserted into the coil but don't hold the coil.

Alternatively just insert a spare spark plug into the coil, and hold the plug body on a ground (hand at top of coil of course), crank and check for spark.Just to be safe don't touch the car while doing this on the remote chance that the spark could find your hand. This happened to me many times with high voltage plug wires and it's damn uncomfortable. On the mini your not really holding the high voltage part so I would think it's perfectly safe but take precautions. If your skittish perhaps use a piece of wood to push the plug against metal.

 

I thought of that but wasnt sure if it would damage the DME or something.

 

Yeah with these new cars you never know. I had a bad coil on the Mini and actually disconnected coils while the car was running to see which one did not affect idle. I was getting a multiple cylinder misfire code. In my experience the misfire codes are not always reliable in terms of identifying the cylinder or reporting multiple cylinders when it's really one.

I'm not clear if you actually have a misfire or if you suspect a false code?
Is the car running rough? My coil was not completely dead because at some rpms car appeared to run smooth but it still was very obvious when it occurred.

If your car is running fine then maybe it's a cam sensor. I read that the ECU determines misfires via the cam sensor although of course it's also used to time fuel injection.
If it is running rough then you need to determine if the coil inputs are good.

I also had a car with a weak fuel injector and it took me about a year to diagnose it (i got very infrequent misfire codes). Only symptom was a slightly rough idle. I finally realized it was likely not a ignition issue and I checked the injector resistance and one was out of spec. Don't know if the Mini injectors are easily accessible but this is an easy check.

 

Its certainly misfiring. I can feel it and I can read it on the live data. I changed the coils and plugs. I swapped around the injectors,

 

I recall a ground wire some have left off that caused problems, any loose wires?

 

Try pulling one of the cam sensor connectors loose or one of the VVT solenoid connectors loose - this will "override" the VVT system. I have had 3 r56 in the past year do this, they will run fine without the VVT otherwise misfire with good plugs, coils, compression, leakdown, etc.

 

Do they always misfire on the same cylinder?

 

I do not recall but I'm thinking 3 or 4, the theory is that the VVT is advancing timing too much or causing havoc in some other way. There are plenty of threads online - a few actually here on this site with similar symptoms and pulling the connector of one of the VVT or cam sensors solves the symptom. There is a local mini shop that I visited with two very good mini guys. They had one of these and ended up replacing the motor after changing everything but the head itself.

 

I would think the cam being out or time would show up in the live data.

 

I think I have the misfire mystery solved. I swapped out the computer and it seems to have solved the problem.

However now I seem to have a new problem. The new computer set does not seem to be coded for traction control. Does anybody know how to do coding?

 

you mean you got the ECU cloned or you're using an ECU/CAS/Fob set?

either way, you need to use NCS expert to recode it.

 

Are you confirming success yet? Interesting idea, I have ISTA-P and spare ECU's, I guess I can go out and try to brick this car, lol.

 

I wish it were this simple. Programming and coding a donor ECU/DME won't make the car start because of security/pairing parameters. There are tools to clone it but some of them can get insanely expensive like AutoHex II.

 

Thank you, to clarify, I also have the matching CAS and key sets for the ECUS, so swapping both should work for the security? I have done this very same thing on BMW's with success.

 

Yes it will work. Be mindful of the mileage though. After few starts it will carry over/keep the higher mileage. If you have the speedo from the donor, then swap it too.

 

Yes, I changed the set so the Vin is wrong for the car. I dont have NCS, I have bavarian tecknich and I think it might do the job, but I dont know how to do coding or command console.

 

Car runs great, but a couple dash lights are on.

 

I'm not sure how Bavarian tecknich works but if it is capable of coding, start with selecting the abs module and from there do coding and/or resetting of the module.

 

Turns out the coding option only comes up on the CAS module, and I cant even access that. Called BavTech and they told me I cant access because the module doesnt match the car, and I need to have it coded by dealer. Worthless! I can get the NCS, but what interface should I buy? I have a Ktag on the way.

 

Ktag is good for cloning your ECU.

The interface you need is called K+Dcan usb cable. you should also get ISTAD to diagnose your car.

 

Thanks for your help. Yes, I got the ktag in case I need to do a clone. I will look at getting the cable asap.

 

Any time brother...let me know how the Ktag performs, last one i bought did not work right off the box.