8 replies to this topic

[mykweb]

afternoon all

Been having a few issues trying to get the Mini throu emissions @ mot

Spec is

MPI block 1293, stage 3 head, 1.5.1 rockers, standard cam, 48mm alloy throttle body, K&n filter, Standard manifold and RC40 backbox.

Car is running an orginal Rover cat

Took the car in afew weeks ago and the emissions were sky high. Swapped the cat and also tightened up the 3 bolts on the downpipe to manifold as it was blowing slightly.

Took it in today and my uncle is saying its running to lean and to adjust teh mixture. But with it being an MPi with an non programmable ECu I can't do anything.

Anyone have any idea's or seen this before.

Mike

[xrocketengineer]

Hi Mike,
I have a general suggestion. Can your uncle check it again with the Oxygen sensor disconnected, to see if the mixture goes normal or rich? My experience is with my daughter's Hyundai that would idle rough sometimes. I hooked the diagnostics but you could not read the sensor voltage in that car. However, I could read when the car was in "closed loop" meaning it was using the sensor. Interestingly enough, every time it was in closed loop the idle was rough. So, I disconnected the Oxygen sensor connector and the car drove perfectly (with the check engine light on). Bought a new Oxygen sensor and no problem since.

I hope that helps,

Ivan

[mykweb]

Hmmm, so could possibily be the Lamba sensor requires replacement.

I will hopefully be taking it back in this week for him to have a look at it.

cheers

Mike

[icklemini]

Whats the emissions reading at?

[mykweb]

These are the readings done on a manual test

Co. 0.00
C02. 13.4
Lambda 1.133
Hc. 54
02. 2.66

Mike

[icklemini]

does it drive OK?

The lambda is a bit high = weak

it *could* be a duff lambda sensor, falsly reading rich thus getting the ecu to go weak,... can you get any live data from the EMS to see what the lambda sensor is telling the ecu?

Edited by icklemini, 19 September 2010 - 04:19 PM.

[mykweb]

Car runs like a dream.

When I stuck the engine back in I did not fit that stupid PBV.

I am running the standard pressure regulator.

What do you mean "live data" from ther EMS. is this from the ACR4 code reader?

I did notice in the components part on the code reader there is a O2 bank volts. is this the communication voltage on the Lambda sensor.

I did try a test of unplugging the lambda sensor and revving the car and I did not notice any major difference. I have not driven it with the sensor unplugged. I will give that a try tomorrow.

Mike

[icklemini]

What do you mean "live data" from ther EMS. is this from the ACR4 code reader?

Yep get the live data out of the ECU (EMS=engine management system), via the code reader..
on the ACR4 it is listed under 'Components' - this shows you what the ECU is receiving...

I did notice in the components part on the code reader there is a O2 bank volts. is this the communication voltage on the Lambda sensor.

Yep.

[mykweb]

Cheers

I went out tonight and let the car warm up and plugged in the ACR4 and got these numbers. All look ok.

Component - - Ignition on - -Car started.

RPM - -0 - -870
Ect - - 14 - - 95
Iat - -14 - -62
MAP - -98.4 - -51
Throttle Position - -5.3 - -4.9
Throttle Switch - -off - -off
Battery - -11.7 - -13.4
02 volts bank - - 1.98 - - Fluctuates between .0.99 - 2.48 -4.75 - 1.49
F/Bank - - off - - on
Coil 1 Charge - - 2.07 - - 1.48
Coil 2 Charge - - 0.04 - - 1.45
injector 2 - - 19.92 - - 1.17
injector 4 - - 19.92 - - 1.17
Stepper - - 131 - - 50
Ignition - - on - - on
Crank Signal - - BAD - - Good
Cam Signal - - BAD - - Good

I disconnected the Lambda sensor plug when the car was running and the numbers went back to 1.95, and stayed. Did not move. as soon as I plugged in again they started to fluctuate again.

i am then assuming the lambda numbers are good and its communicating with the ECU. Could the lambda still be faulty?

My uncle did say it might just need warmed up more before the emmissions were carried out, maybe this is the case.

I also stuck the orginal throttle body back on the car and reconfigured the stepper motor and position.

Mike

Edited by mykweb, 20 September 2010 - 05:46 PM.