When a remap doesn't work

[Mr Peel]

What might be going on when a remap won't work? Anyone had this? Specialist has had two attempts at a straightforward stage 1 remap on my Mini. Slightly leftfield as it's a Countryman Cooper S, but it's still the well-known N18 engine. Power dropped off massively on the rolling road towards the top of the rev range with the map on it. Car is fine as standard.

Specialist has run diagnostics, but now seems to have run out of ideas. Does this happen often? Should I try someone else?

Never had a car mapped before and was really looking forward to this. Am now like a disappointed child, which is never a good look for a middle-aged man...

[NateWM]

Sounds like it's running out of fuel at the top end of the rev range. Might be worth taking it to a dedicated Mini tuner like 1320mini or Orranje.

[Durzel]

How specialist is this specialist?

I'm not remotely an expert but power dropping off rapidly would suggest to me that the ECU is unhappy about something it is seeing at that point - air/fuel mix, pinking, etc.

[bobbo89]

As others have said, how specialist are they?

Is it definitely just a stage 1 map they're putting on? Does it require anything else such as an uprated airbox or induction kit?

[Mr Peel]

It had an ITG air filter and uprated spark plugs fitted at the time the 1st effort failed.

[popeyewhite]

Mr Peel said:

Power dropped off massively on the rolling road towards the top of the rev range with the map on it.

..and has the power increased much lower down? Dd you look at the lower rev range bhp/torque curve on a graph at all?

[Mr Peel]

popeyewhite said:

..and has the power increased much lower down? Dd you look at the lower rev range bhp/torque curve on a graph at all?

Yep, much increased power lower down. I saw the graphs.

[d8ns18ly]

Where are you taking it to be mapped? I had my N18 engined Mini JCW mapped up at Lohen and had no issue at all

[Mr Peel]

d8ns18ly said:

Where are you taking it to be mapped? I had my N18 engined Mini JCW mapped up at Lohen and had no issue at all

There.

[popeyewhite]

Mr Peel said:

popeyewhite said:

..and has the power increased much lower down? Dd you look at the lower rev range bhp/torque curve on a graph at all?

Yep, much increased power lower down. I saw the graphs.

Then the map has worked. The model for the map you had was to take some power from the top, add a bit, and increase the power lower down where you're likely to use it more. A popular mapping choice.

[xjay1337]

What tuner is it?

[Durzel]

popeyewhite said:

Mr Peel said:

popeyewhite said:

..and has the power increased much lower down? Dd you look at the lower rev range bhp/torque curve on a graph at all?

Yep, much increased power lower down. I saw the graphs.

Then the map has worked. The model for the map you had was to take some power from the top, add a bit, and increase the power lower down where you're likely to use it more. A popular mapping choice.

The car shouldn't hit a brick wall though further up the rev range though, should it?

If the remapper thinks its not right then that would be telling, although the fact they don't know what it could be could also be telling.

[popeyewhite]

Durzel said:

The car shouldn't hit a brick wall though further up the rev range though, should it?

No, it shouldn't, though the OP only said it "dropped off massively". It's all subjective.

Durzel said:

If the remapper thinks its not right then that would be telling, although the fact they don't know what it could be could also be telling.

Yes.
It sounds as if the intention was to shift power further down the rev range but something's not quite right. He'll have to put the original map back on, unless he's damaged the ECU it should be easily done.

[J4CKO]

Could be fueling as mentioned.

Maybe look at the waste gate, possibly a boost leak, plus gaps have caused his for me in the past, check the gaps and possibly close them up a smidge. Not sure how they are set up but might be a MAP sensor issue.

Could be a coil pack breaking down under load or a duff plug but that usually is accompanied by fault codes and bucking or misfiring.

Sounds like the map has been applied but the hardware is struggling

[bobbo89]

If it’s hitting a brick wall or dropping off massively it could point to a boost leak at high pressure. Suspect the tuning company would check all of this though.

Do these run sound symposers?

[Robmarriott]

Boost cut in the ECU?
Tired fuel pump?

Do you have a graph? Is it actually falling off or just flattening out?

[popeyewhite]

Robmarriott said:

Do you have a graph? Is it actually falling off or just flattening out?

Exactly... .

[DoYouEvenBoost]

Has the tuner been monitoring the AFR during mapping/rolling road? That will help answer the is it fuel question.

If it's fuel you'd see the AFR go lean at the top end so then it's just work back through the fuel system. Could be injectors so check the duty on them, then possibly fuel pump, if it's getting a bit old it could be struggling to flow the required volume to keep up with the map.

[Hol]

The thing to remember, is that used cars come with used/worn parts attached.

A mapper could have three seemingly identical cars in for the same level of tune and encounter three distinct outcomes.

1. Could respond perfectly, and just need small tweaks to maximise the power from the planned map.
2. Could have a small mechanical issue, such as a leaking boost pipe or solenoid, that is easily identified and once that is fixed, can be mapped the same as #1.
3. Could have a deeper mechanical issue, that doesn't throw up any error codes, has no visible problems on a standard map and requires deeper/specialist investigation.


Unfortunately, I think the OP's car is likely somewhere between 2 and 3. But, once sorted his car will be fine.

[Mr Peel]

popeyewhite said:

Robmarriott said:

Do you have a graph? Is it actually falling off or just flattening out?

Exactly... .

Definitely falling off, dramatically so. I didn't ask for a copy of the graph, regrettably.

Interesting mention of high-pressure fuel pump. Tuner's own website states: "One of the common problems on the Gen 2 1.6l turbo charged MINI has always been the high-pressure fuel pump. Even on the revised N18 engine, the high-pressure fuel pump failing still seems to be a common issue. Some common signs your MINI high-pressure fuel pump may be failing can be that your MINI struggles to start from cold, idles poorly or has hesitation to rev when driving the car hard."

I haven't noticed any of the above, but one of the techs claimed there was slight hesitation under hard acceleration when he drove the car.

They didn't suggest the fuel pump as the problem though. Would it show up on a diagnostics check if it was on the way out?