4 replies to this topic

[alex's 30]

1998 MPI Shows 13v at battery(running)
14v at alternator
under load (lights on) 12.6 at battery
14v at alternator
Any ideas where the voltage drop could be coming from?
Earth in boot is fine, drive belt ok not slipping.
Also there is no earth strap on the upper engine steady as on earlier models. Does this model have one?
Thanks in advance.
Alex

[xrocketengineer]

1998 MPI Shows 13v at battery(running)
14v at alternator
under load (lights on) 12.6 at battery
14v at alternator
Any ideas where the voltage drop could be coming from?
Earth in boot is fine, drive belt ok not slipping.
Also there is no earth strap on the upper engine steady as on earlier models. Does this model have one?
Thanks in advance.
Alex

According to page 25 of this posting attachment (Engine - repairs or page 79 of the PDF document), the MPI is supposed to have an earth strap on the upper steady. Other than that, I'll let the more experienced people comment on the voltages.
Ivan
http://www.theminifo...x...st&id=68239

Edited by xrocketengineer, 25 April 2009 - 10:17 PM.

[L400RAS]

1998 MPI Shows 13v at battery(running)
14v at alternator
under load (lights on) 12.6 at battery
14v at alternator
Any ideas where the voltage drop could be coming from?
Earth in boot is fine, drive belt ok not slipping.
Also there is no earth strap on the upper engine steady as on earlier models. Does this model have one?
Thanks in advance.
Alex

Hi Alex,

The voltage drop is bound to happen under load, yes when the lights are on etc. as long as it doesnt go below 12v it'll be ok. I guess you are testing this while stationary, ie at idle speed of say 900-1000rpm?
Try testing it again, but reving up to around 2500-3000rpm, ie 60mph speeds. This should give you less of a voltage drop as the alternator will be spinning faster, thus able to chuck out more amperage (although don't be disappointed if it still drops). Do you have a fatory fitted volt gauge? take a look at it while driving, if its above 13v almost all the time, then you'll be fine. Are you getting a dead battery after a long night drive?

Regarding the earth strap, both of mine have one, and i have replaced them, add one if you wish, can't do any harm.

Ryan.

Edited by L400RAS, 26 April 2009 - 01:59 PM.

[clydecat]

Alex,
My 2000 model has an upper earth strap. I had an issue where the voltage was normal (13.8V) while the car was sitting, but as soon as I started moving it would drop to 12V, turned out the earth strap was loose. I would definitely suggest adding an earth strap.

Edited by clydecat, 27 April 2009 - 04:00 PM.

[alex's 30]

Hi thanks for the info will add earth strap and see if any improvement.