20 replies to this topic

[mina08]

Ok i know there are threads on here that look at this area, but i feel there is no real answer and thats understandable.

My problem is that the car runs slightly lean especially under 2500, after that its ok but could be slightly better, so i am looking for a solution that will help increase fuel in a small way.

 

My Car has had the engine rebuilt by a professional mini mechanic, and fitted.

 

All new sensors, checked all wires for damage or problems

New Vac pipes

New petrol filter fitted 5000kms ago

new fuel trap

new plugs after 1000kms showing white colour

new leads

 

Performance wise

Flywheel

Kent Cam 274 (specifically for injection)

LCB with single back box

Cat delete pipe

K&N filter in orig housing

mildly ported head

 

So i am sure in saying that the performance bits has pulled the car to be running Slightly leaner.

What could be a cost effective way of increasing fuel, obviously with the Rover MEMS being unable to adjust it its not an option. The fuel pump is running great and the injector is running good.

 

Options

 

Adjustable fuel pressure regulator

http://www.ebay.co.u...4-/371436494447

 

New programmable ECU

http://www.emeraldm3d.com

http://twinkam.co.uk...Products/SC0127

 

or throttle body and ECU

http://twinkam.co.uk.../Products/SC218

 

My Car

1992 SPI 1275, 274 kent CAM, LCB, K&N

 

ticks over at 700/750

 

does anyone think i could ever so slightly increase fuel through the injector with an adjustable FPR, or had any success with other trickery.

 

cheers

Edited by mina08, 28 May 2017 - 04:01 PM.

[Steve220]

Out of curiosity, how do you know it's running lean?

[genpop]

You may change fuel trim and idlespeed by means of mems rosco.At the same time you will see if the engine runs on open or closed loop. Have a look here : http://www.theminifo...-reader/page-11 and here:http://alum.wpi.edu/...c-protocol.html

A bigger injector would propably solve it as well.

Leopold

[mina08]

Out of curiosity, how do you know it's running lean?

The colour of the spark plugs, and flat spots in the rev range.

[mina08]

You may change fuel trim and idlespeed by means of mems rosco.At the same time you will see if the engine runs on open or closed loop. Have a look here : http://www.theminifo...-reader/page-11 and here:http://alum.wpi.edu/...c-protocol.html

A bigger injector would propably solve it as well.

Leopold

Thanks i will take a look, any recommendations on other injectors? I am getting the cars ecu read again at the end of the week just to check all sensors again.

Edited by mina08, 29 May 2017 - 03:24 PM.

[Sprocket]

This sound like a can of worms. Clearly something wrong and attempting to richen up the fueling by other means is not a fix.

 

I should add that there is nothing in your engine build you have listed that would not allow the ECU to adapt. You have a fault with the set up somewhere. Have you had a diagnostic test done on it yet?

 

I was under the impression that you can only tune the Idle CO with ROSCO, and even then only on Open loop systems (those without catalytic converters and lambda sensors) which were never fitted to the mini. Happy to be proven wrong. There's a Rover service training video on youtube that explains this, i'm sure

Edited by Sprocket, 30 May 2017 - 11:21 PM.

[mina08]

This sound like a can of worms. Clearly something wrong and attempting to richen up the fueling by other means is not a fix.

 

I should add that there is nothing in your engine build you have listed that would not allow the ECU to adapt. You have a fault with the set up somewhere. Have you had a diagnostic test done on it yet?

 

I was under the impression that you can only tune the Idle CO with ROSCO, and even then only on Open loop systems (those without catalytic converters and lambda sensors) which were never fitted to the mini. Happy to be proven wrong. There's a Rover service training video on youtube that explains this, i'm sure

A full Diagnostic is getting done this weekend so i will know more then, i have read more and realise the only way to tune an SPI is through an aftermarket ECU and maybe adding the throttle body/injector upgrade, but sure i want to see that all sensors are working perfectly before i add anything to the engine management.

[mina08]

Had a full diagnostic today all parts and sensors working as they should be and no faults, so i am putting down to the new Cam. 

[Sprocket]

I still think you are going in the wrong direction with this, but it seems you are set on doing something else.

 

Like I said, there is nothing in the specification you suggested that would cause the issues you are having. The fact that you say it is idling at 700 -750 rpm tells me there is something fundamentally wrong, that your 'diagnostic' technician has not picked up on.

 

Normal

Idle 850rpm

Stepper position around 35 steps (Warm idle)

MAP around 35kpa/ 500mmhg

Idle advance 15 degrees +-5

Lambda Volts 0.2/ 0.5 fluctuating (200/500 milliamps)

Coolant temp 88c

Throttle Position sensor 0.5/4.5 volts

 

Have you thought about doing the diagnostic yourself? There is software available on open source license that will allow you to run and capture a data log of all these parameters on a running and driving engine. Check it out here http://www.rmrsoft.com/mems/ but you will have to make your own communications cable.

[mina08]

I still think you are going in the wrong direction with this, but it seems you are set on doing something else.

 

Like I said, there is nothing in the specification you suggested that would cause the issues you are having. The fact that you say it is idling at 700 -750 rpm tells me there is something fundamentally wrong, that your 'diagnostic' technician has not picked up on.

 

Normal

Idle 850rpm

Stepper position around 35 steps (Warm idle)

MAP around 35kpa/ 500mmhg

Idle advance 15 degrees +-5

Lambda Volts 0.2/ 0.5 fluctuating (200/500 milliamps)

Coolant temp 88c

Throttle Position sensor 0.5/4.5 volts

 

Have you thought about doing the diagnostic yourself? There is software available on open source license that will allow you to run and capture a data log of all these parameters on a running and driving engine. Check it out here http://www.rmrsoft.com/mems/ but you will have to make your own communications cable.

Hi Sprocket

Just want to check everything before i change any part.

I have a closed loop system, all the values you have listed are what was shown on the reader, except for the idle, tested all actuators and sensors.

what else should i consider looking into? Cam shaft timing maybe?

cheers

Edited by mina08, 04 June 2017 - 06:34 AM.

[Nu2mini]

I'm not quiet sure what you are trying to fix here. I have returned to your original post several times to see what the problem is.

 

You believe the car is running 'Lean' :- Evidence is "The colour of the spark plugs, and flat spots in the rev range."

You also say "My problem is that the car runs slightly lean especially under 2500".

 

Observations.

1) Is the Spark plug analysis accurate to say the mixture is lean.

2) What exactly do you mean by 'Flat Spot'. Is the car hesitating in any way or are you saying that beyond 2500 there is a noticiable difference in the way it pulls. This would not be unusal on an 'A Series' even with a standard SPI CAM. where it comes onto CAM at much higher revs than a more modern engine.

3) You say all the diagnostics, other than idle are within range. This alone is enough to question if there is anything actually wong

3) I'd exercise caution before doing anything. First understand the issue, then identify the cause. Anything else could be a costly 'Fools Errand'  

[mina08]

I'm not quiet sure what you are trying to fix here. I have returned to your original post several times to see what the problem is.

 

You believe the car is running 'Lean' :- Evidence is "The colour of the spark plugs, and flat spots in the rev range."

You also say "My problem is that the car runs slightly lean especially under 2500".

 

Observations.

1) Is the Spark plug analysis accurate to say the mixture is lean.

2) What exactly do you mean by 'Flat Spot'. Is the car hesitating in any way or are you saying that beyond 2500 there is a noticiable difference in the way it pulls. This would not be unusal on an 'A Series' even with a standard SPI CAM. where it comes onto CAM at much higher revs than a more modern engine.

3) You say all the diagnostics, other than idle are within range. This alone is enough to question if there is anything actually wong

3) I'd exercise caution before doing anything. First understand the issue, then identify the cause. Anything else could be a costly 'Fools Errand'  

yes there are slight flat spots under 2500rpm after that the engine pulls well, had all the clearances checked on the valves and are all set to the recommendations set out by kent cams 0.0016, it mainly happens in any gear at around 2000rpm

The spark plugs colour shows its running lean, i have a nice grey black colour on the tip of the exhaust

I am not going to go out and spend a large amount on stuff until i know why its doing it, maybe like you said it could be normal, if so then i may consider an programmable ECU

[Scott MPI]

Id say it's the cam timing too, I've been doing a lot of research on the subject, worth checking

The first think you would want to do with a new ecu is ajust the spark timing

So may as well try adjusting cam timing to suit new set up

[mina08]

re did the valve clearances again and now notice a 50% improvement...

[r3k1355]

Have you tried fitting a new injector or having the old one properly cleaned and flow tested?

 

Most old injectors loose about 5-10% flow rate (sometimes more) as they age and get filled with crud.

People spend ages chasing fuelling issues, but never once think to look at the 20 year old injectors the car runs.

Edited by r3k1355, 07 June 2017 - 09:54 AM.