10 replies to this topic

[R32Egor]

I completed some work on the mini including a full new maniflow injection manifold + RC40 exhaust (keeping the CAT), new coil, leads, plugs, distributor cap + rotor arm and then the car was setup (motion gap and stepper motor) according to MEMSFCR instructions etc.

The car was then running well (as far as I could tell). I reset the ECZ values as the long term fuel trim was -30% and i beleived this was down to the car running rich (I know it was as the plugs were black and the lambda sensor circuit was defect.)

 

I then went off to an EPIC IMM2023 in Tuscany Italy with some unbelievable roads and an awesome 3 days of some HARD driving😁😁😁😁.

 

Got home and decided to check everything out and these are my findings -

 

long term fuel trim was back at -28%

Stepper motor 33 (at temperature)

MAF 30 - 33 at idle

motion gap still ok

 

Due to the very low Long term fuel trim i checked the plugs and they looked good with no. 2 & 3 slightly blacker than the other outer two.

now because The lambda sensor with the maniflow is reading the exhaust from the outer two exhaust ports only could this be the reason why my long term fuel trim is so low???

 

Should i be worried with this low trim our should I concentrate on the short term fule trim??

 

The emissions are a pass so I am not thinking CAT??

 

My exhaust pipe at the back is black.

 

Any ideas???? Do I have a problem??

 

 

 

 

[viz139]

It sounds like you have a LCB with the lambda in the downpipe from cylinders 1 and 4.

We found in order to pass the emissions test in Ireland we had to move the lambda to the Y piece.

[R32Egor]

Yes that is correct - but I pass my emissions right now in the condition above -

 

Would I be right in saying that because the Lambda sensor is in the downpipe for cylinders 1 & 4 then the Long term fuel trim I am reading is just compensation for the position of the Lambda and I should not worry??

[sonscar]

I would expectfuel trims to be in single figures.Removing a third of the commanded fuel(from the fuel map)seems excessive.Excess fuel pressure?leaky injector?Just my thoughts with non Mini injection.Steve..

[R32Egor]

OK - took apart the pressure regulator as the injector looked ok -

 

 

Can somebody tell me if the 2 washers are meant to be in the positions that you can see from the image? or are they extra and therefore increasing the stiffness of the spring and obviously increasing the fuel pressure?

 

his might account for the above fuel trim problem - as the SPI is standard (apart from stage 1 ).

 

Thanks 

[genpop]

Hi R32Egor,

i can not remember that the pressure regulator has these two washers.They look like coper seal rings, i would leave them.You could do a pressure test afterwards. It is very easy at low cost.An y-peace from the windshield wash system some rubber hose and a cheap manometer 0 to 3 bar.Connected to the incoming fuel line should show about 0,9 to1 bar!

[R32Egor]

Update - FIXED😁😁😁😁😁

 

2 xears of getting the motor to run correctly and replacing nearly every sensor and checking and checking - The main problem was the above picture - there should be no washers.

Took them out and hey presto mini runs better and after resetting the ecu the long term fuel trim is now +5 .

 

Had to readjust the stepper motor position slightly but the motor runs so much better top end.

 

will look at the trim everyday this week as i will be driving everyday but looks so good.

 

So the person (idiot) who had it before thought that just making more pressure would make the car faster - they forgot the ECU would compensate for this.

 

I am so happy after 2 years!!!! I just wish I had found it before the IMM but there you go and talking to Oz Osbourne form Osbourne Automotive Preparation at the IMM lead me in this direction for the fix👍👍

[sonscar]

I did mention high fuel pressure.Steve..

[R32Egor]

Yes you did thanks for pushing me in the right direction

[R32Egor]

Now LTFT is +7%
3% of that will be down to the E10 fuel so we are talking abot +4% so perfect
Going to find some super E5 fuel and see if there is any difference

[R32Egor]

Another check and now the 

 

LTFT = 0% - I know I don't believe it either - going to check next week again and post the finding a final time.