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[MutantCav]

Since changing the alternator on Wednesday the car now runs fine..in fact better than it did as I fixed a couple of other bits while I was at it...

One thing I notice now though (didnt do it before) when first starting it the power fluctuates for a short while before settling down...MID goes dim on and off with the change of power too...only happens for about 10 seconds or so...

I remember seeing this was a sign of something but cant remember what...battery on its way out?? The one I put on was a quick fix and not 100% sure how good it is, or how charged it was...have another on charge which I will put on when its 100%

[tunnie]

poor / loose earth?

[MutantCav]

Wasnt an issue at all before the alternator was sorted and only happens for a few seconds when engines started...although I guess I could check the earth on the alternator is tight and the bolts are both fully done up??

[Dingleberry]

I have this with mine, i put it down to that air thing that sounds like a hoover when you first start up, purely because it doesnt make any noise now and the lights dim on and off for the first 10-20 secs of driving ?

[iainb]

Try to get a Midtronics battery tester as the suspect is the battery.
The old multi meter will only show V+ not the algerythum ?
(spelling isnt my strong point)
I have a simular issue and will get a new battery although the V+ shows 13.2 but can hardly throw the starter for 30 seconds

[bigdods]

My old 2.5 did this when the SAI was knackered. For the first 30 seconds after starting the revs would be up to 800, down to 300 and repeat accompanied by dimming of lights etc. I just unplugged it , problem solved.

[MutantCav]

Ahh you see, one of the other things I sorted was indeed the SAI pump as it was like a jet engine winding up on start up, new ones quiet and time it goes wrong would tie in with the extra effort from the SAI pump...

Will get another battery on the car tomorrow anyway and see where we are then and throw the old one if its faulty...I have 7 so can afford to lose one lol

[Sir Tigger KC]

Check out MDTM's post on repairing the alternator, there's abit on there about fluctuating power? :-/

[MutantCav]

Disconnected the SAI pump and indeed the fluctuation has gone away...will check out DTDM's post too

Edit: Checked it...I simply swapped the brushes/regulator from another alternator...not sure why the SAI pump is causing the issue, maybe overloading a failing alternator?? Or could it just be the wirings a bit dodgy to the SAI pump or the SAI pump I put on it dodgy causing a faulty earth??