10 replies to this topic

[mojox]

I have an SP ACR4 & am checking out poor idling on a 1994 car. All tests for sensors appear ok, as do readings for sensors. No faults are stored, but the idle goes up & down 850 - 1200 every few seconds - worse when hotter. I know plenty about injection systems and have a good knowledge of this car & read virtually every thread on this forum.

Apart from the stepper being reset now or needing replacing. I can't (so far) find anything that would cause this idle fault having gone through all the normal tests - e.g. coolant temp ok. air temp ok, map sensor ok, throttle pot reads ok thru range, relays operate, wiring visual checks ok including connectors, etc. There's obviously something wrong - perhaps wiring corrosion or something - from experience with other newer makes of car when there are no faults on the diag. checks then normally it's a mechanical problem.

I changed the Oxygen Sensor just to rule it out, and the only other point I've noticed is the engine runs to a max temp of about 83ºC today according to the ACR4 readout (at about 18ºC outside air temp). Can anyone tell me if this temp reading being low at 83ºC would cause the idle problem? I think not, but am sure this engine should get hotter - at least 88º & should rise slowly until the cooling fan cuts in (which it didn't). The ACR 4 manual says until 82ºC is reached the engine won't be on hot idle setting. I'm thinking a new thermostat could sort the temp. being too low, however as the idle was erratic before reaching 80ºC don't think this will solve the idle fault.

[james0133]

It sound like you know your stuff when it comes to Minis and as I am new to them I probably won’t be much use to you but as you have checked all your electrics and found no fault, have you checked your valve clearances or done a compression check?

I am getting a slight hunting at idle on my 98 Mini Cooper and wanted to get some diagnostic software. How do you find the SP ACR4 and is it worth getting?
What other kit do you have to run it, I presume you just need the lead and pod and do you know if it will work with the MPI?
Good luck with finding the problem.

[ICAM]

I have an SP ACR4 & am checking out poor idling on a 1994 car. All tests for sensors appear ok, as do readings for sensors. No faults are stored, but the idle goes up & down 850 - 1200 every few seconds - worse when hotter. I know plenty about injection systems and have a good knowledge of this car & read virtually every thread on this forum.

Apart from the stepper being reset now or needing replacing. I can't (so far) find anything that would cause this idle fault having gone through all the normal tests - e.g. coolant temp ok. air temp ok, map sensor ok, throttle pot reads ok thru range, relays operate, wiring visual checks ok including connectors, etc. There's obviously something wrong - perhaps wiring corrosion or something - from experience with other newer makes of car when there are no faults on the diag. checks then normally it's a mechanical problem.

I changed the Oxygen Sensor just to rule it out, and the only other point I've noticed is the engine runs to a max temp of about 83ºC today according to the ACR4 readout (at about 18ºC outside air temp). Can anyone tell me if this temp reading being low at 83ºC would cause the idle problem? I think not, but am sure this engine should get hotter - at least 88º & should rise slowly until the cooling fan cuts in (which it didn't). The ACR 4 manual says until 82ºC is reached the engine won't be on hot idle setting. I'm thinking a new thermostat could sort the temp. being too low, however as the idle was erratic before reaching 80ºC don't think this will solve the idle fault.

How is the stariting condition early morning? By right if your temp sensor having problem, you shall have a difficulty when your 1st start of the day.

[mojox]

How is the stariting condition early morning? By right if your temp sensor having problem, you shall have a difficulty when your 1st start of the day.

Hi ICAM, starting is fine, temp reads fine up to 83ºC, just won't get any hotter - I'm thinking thermostat stuck open.

Edited by mojox, 29 September 2008 - 12:23 PM.

[mojox]

It sound like you know your stuff when it comes to Minis and as I am new to them I probably won’t be much use to you but as you have checked all your electrics and found no fault, have you checked your valve clearances or done a compression check?

I am getting a slight hunting at idle on my 98 Mini Cooper and wanted to get some diagnostic software. How do you find the SP ACR4 and is it worth getting?
What other kit do you have to run it, I presume you just need the lead and pod and do you know if it will work with the MPI?
Good luck with finding the problem.

Hi James0133
Thanks for the reply, am used to many electrical faults especially Renaults, however without the stepper motor adjustment facility it makes the fault much more difficult to pinpoint.
The ACR4 does diagnose/test most components but the stepper motor tune using pod No. 1 is only possible on the pre-cat open loop SPi models. Someone with a Pod no.3 has mentioned setting the stepper but I don't know if that was on an early pre cat car or not. As for the MPi I think pod 2 does that - just need a different lead to the SPi minis. Easy enough to get hold of - try ebay user alltooled-up - he does the best value ACR4's I can find on the net.

[james0133]

Cool thanks. I'v been watching alltooled-up's action and I think I will buy one from him and then I will just have to get the correct lead and pod 2.

If I buy the ACR4 I will check what temp my Mini runs at and let you know.
On mine the rad and fan is at the side and the fan is constant, running off the crank and it has no clutch. So my engine, never seems to get very hot at all.
Optimal combustion temperature is 84C so it is not a bad thing but obviously it is more the hunting of the revs that you are trying to get to the bottom of.

[mojox]

This Mini has the normal fan plus the electric one.

Some cheap pods on ebay but check out Pod 3 as I think it covers all spi & mpi models for a little higher price Does anyone know for sure if Pod 3 allows the stepper motor to be setup on the later SPi models with catalytic convertor/closed loop system??

Edited by mojox, 29 September 2008 - 09:01 PM.

[datsun100a]

I would try unplugging all sensors to see what happens. It will use default values and might show a fault of some sort. All vac lines ok?

[yasan39]

It sound like you know your stuff when it comes to Minis and as I am new to them I probably won’t be much use to you but as you have checked all your electrics and found no fault, have you checked your valve clearances or done a compression check?

I am getting a slight hunting at idle on my 98 Mini Cooper and wanted to get some diagnostic software. How do you find the SP ACR4 and is it worth getting?
What other kit do you have to run it, I presume you just need the lead and pod and do you know if it will work with the MPI?
Good luck with finding the problem.

Hi James0133
Thanks for the reply, am used to many electrical faults especially Renaults, however without the stepper motor adjustment facility it makes the fault much more difficult to pinpoint.
The ACR4 does diagnose/test most components but the stepper motor tune using pod No. 1 is only possible on the pre-cat open loop SPi models. Someone with a Pod no.3 has mentioned setting the stepper but I don't know if that was on an early pre cat car or not. As for the MPi I think pod 2 does that - just need a different lead to the SPi minis. Easy enough to get hold of - try ebay user alltooled-up - he does the best value ACR4's I can find on the net.

hi
Can u pleas help me with this code readers give me some info about this I need to by one for a spi with 3pin lead

this is my e-mail [email protected]

nice day to you

[noz]

mine had the hunting problem when i first got it. would sit at around 850 then run up to about 1300 and cyle back
down as if it was hunting.
now i can't tell u what was done to sort it but the man who fixed it was the mechanic from p and l. all i remember was him plugging in
a device and i think trimming something up.

sorry i can't be of any more help tho

[tmsmini]

I am not that familiar with the SPi, so I am hesitant to post. However some SPi have a throttle idle switch which may affect idle conditions. I will look for some documentation to verify this. I believe it has been mentioned in a few posts, but I am not sure exactly what problems it will cause.

The Rover 3 pod is required for MPi MEMS 2J ECUs.

EDIT: Looks like the throttle switch would not apply as:

" its the throttle switch, its totaly different and only on the SPi Mini up to 93, it fits behind the throttle pedal, a spring pulls the throttle pedal back to ensure the switch is closed, there is a circular disc on the throttle pedal arm that acts on the switch, it is this switch that is the problem. This switch provides the ecu with inforamtion telling it that the engine is in an idle condition, if its stuck, when you press the accelerator, the ecu still thinks its in an idle condition yet the engine speed is rising, the ecu then retards the ignition and backs off the stepper, this causes the symptoms you are experiencing."


Have all the tubes and elbow connectors been checked for cracking?

Edited by tmsmini, 22 October 2008 - 08:14 PM.