Have an R56 JCW with 66k on the clock and recently had it stage 1 remapped at a well known mini tuner

It really has transformed the car and produced reasonably healthy figures of 239 bhp / 330nm torque.

All is well and good bar when I change gear between 4 and 5k under load, it seems to judder ever so slightly and the revs drop below 4k before power comes back.

Doesn't happen under 4k or over 5k rpm

Doesn't seem to happen when I let off the throttle in the same gear between 4 or 5k rpm either.



It's going back in for coilovers and they have kindly offered to take it out and see if they can replicate it when it does

But i'd like to know your initial thoughts on this

Stock car bar high flow air filter and NGK iridium spark plus which where fitted just prior to the remap / Dyno



Cheers

 

Bump....

Still suffering this issue - wondering how it can be boost related if it doesn't occur when I remain in gear and rather does it during a gear change between 4 and 5k?

Should I post in JCW forum?

 

Try and isolate the issue. Go back to the previous tune, symptoms still present? Look at the parts added just previous to the ECM flash.

Possible things to try or confirm, swap

• Data log O2, MAF, MAP, timing observe
• Confirm plug type, heat range
• Validate plug gap
• Confirm plugs torqued properly
• Coil connections to plugs seated properly
• Electrical harness connections to coils seated properly
• Swap back in old plugs

That's where I'd start. I'm sure others would have some additional ideas of what to validate/check.

 

Thankyou for the reply,

It's complicated slightly by the issue that it was initially in for what turned out to be ECU repair and a new junction box after a breakdown. I had it stage 1 mapped once the ecu was repaired and prior to collection, at the time as part of the map it has colder plugs (I suspect NGK iridiums) installed and pulled very healthy figure and a healthy dyno graph (all done by Lohen - a mini tuning specialist here in the UK - who have said they haven't heard of this issue i've head before and it needs to go in for diagnosis).

Regarding logging - I don't have the ability to do this so will have to go back in for this. The car's getting to the point it's becoming unenjoyable :(

I'll replace coilpacks see if this makes a difference and it has a GFB DV+ waiting to be installed.

 

I thought i'd bump this in case anyone had any further thoughts.

The car is now on 73k, and the issue is still apparent - between 3900 and 4500k revs - basically change any gear then and there is an immediate hesitation while it drops below that rev range then the power comes in, all in about half a second or so. Happens in all / most gears. Doesn't occur either below the 3900 or above 4500 and pulls strongly to the redline.

It hasn't gotten any worse (or better) in that time.

I've had general servicing done (fluids / spark plugs) along with all coil packs last year but no improvement.

My thoughts were either new injectors, or a walnut blasting de-coke (though this is an N18, will it need benefit from this?)

Anyone else able to offer insight? I'd love to solve this as I want to be able to enjoy the car properly again!

Thankyou for reading / offering any input.

 

Automatic or Manual transmission?

 

HI @njaremka - it's a Manual transmission

 

When you say judder, make me think clutch. However, without driving the car, I can’t say for sure. Do you have a boost gauge? Unfortunately, it’s really difficult to diagnose feelings and sounds over the internet…

 

Was it doing it before you had it tuned?

 

It's tough isn't it as it's very subjective. I don't have one but i'm tempted to throw an Ultragauge II on to see what it shows if that helps?

It initially broke down due to ECU damage, and was towed to the specialist (who is also a well known mapper) - initial thought it was HPFP but after a month and $2000 of investigating it was diagnosed as the ECU, which was repaired. Once repaired, I decided to have to stage 1 mapped before collection which in hindsight I shouldn't have done so I could narrow down the issue.

I do recall when it was collected that the footwell module had to be re programmed in as when I collected / went to start the car up, the lights wouldn't function automatically etc. This was reprogrammed fine with no issues since though.

I know I have a battery on it's way out but this won't be causing the issue of course.

 

Do you still have a dual mass flywheel?

My 2013 S had something similar, can be replicated at 4,000 RPMs by letting off the throttle and then immediately going full throttle..I'll feel a jolt and then it will take off. I diagnosed it as a failing flywheel, and fortunately for my wallet I was right. No more judder for only $700 - clutch and new dual mass flywheel.

Cheers