3 replies to this topic

[Andrew4Minis]

My MPi is running perfectly now and thinks for the Forum for your advice on the cooling system! It's done the run to & from work, a round trip of some 75 miles, for several days now and an extremely accurate fuel MPG check (brim full to brim full) has given a reading of 47.5 MPG-not bad for a car that moved like a stabbed rat on occasions!

 

The tick-over speed has settled down at 800 RPM once it's warm and is only about 1,100 when it's cold, which is just what I thought it should be. However, when the fan cooling fan cuts in, after a spirited run or a stand in traffic, the revs rise to 1,500 and on one occasion 2,000, which is unnerving, to say the least. Oddly enough, when I switch the engine off, leave it for about 10 seconds & start it again it behaves perfectly! 

 

Is this an engine management problem that needs a computer to fix (I can get hold of one) or is it something more prosaic? Any ideas?

[KernowCooper]

Sounds as though the stepper motor is upping the revs after the ecu sees the voltage drop the fan is drawing, not uncommon to see a couple hundred revs, and that applies not to MPI Minis but cars with ecu's in general, but those revs are a bit to much. Are you sure your car is charging ok and the ecu's not taking the revs up that high to maintain voltage. Do a voltage test and see what readings you get before and after the fan comes in and when the revs go up.

[Andrew4Minis]

Thanks-brilliant advice! It might explain the reluctant starting and a battery that flattens with monotonous regularity! I'll check out the running voltage, which ought to be 14.4 volts when running & if it's not, I'll investigate further.... 

[Badboytunes]

Our does the same although the revs rise to abou 1000-1200. As for thebatter flattening, how old is it. I had to replace the one in ours as it had a dead cell and would flatten after a cpl of days. I now have a pug 306 diesel battery , 086 IIRC.