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Flickering Alternator Light
ttalps2000 - 28/7/18 at 03:53 PM

My alternator light has started to flicker! More going dim to not so dim and back to dim again. The alternator is not that old. My battery had a bit of a heat issue, but has always charged fine and kept its charge etc. Battery is still keeping a charge as it is still starting the car ok etc.

Anyone else had similar and found a conclusion? Alternator is one of the small denso units


JC - 28/7/18 at 04:24 PM

Start with the easy....check the alternator Earth strap is secure?


russbost - 28/7/18 at 04:49 PM

Double check ALL connections & wiring to the alternator including those to the warning light, I seem to remember Denso are bolted rather than push on? No sign of overheating on any terminals?
Try using jump leads to supply a direct earth & +ve feed from batt to alternator (Carefully!) if still no different then almost certainly the rectifier partially failed, unit will still charge, but probably at a lower rate than normal. Depending how the rectifier has failed it can cause a slow drain on the battery which you would be able to confirm with an ammeter


gremlin1234 - 28/7/18 at 04:58 PM

quote:
Originally posted by JC
Start with the easy....check the alternator Earth strap is secure?
totally agree,
also check fan belt


ttalps2000 - 28/7/18 at 05:05 PM

the nut had fallen off the output lead post, re-connected and all working fine again now! CARS!!


russbost - 28/7/18 at 05:11 PM

Probably took you longer to make the post than it did to fix the problem!


ttalps2000 - 28/7/18 at 05:41 PM

problem was, i didnt have a volt meter with me to be able to check the alternator! Went door knocking and one of my neighbours had one in the end!


JC - 28/7/18 at 07:44 PM

Son had exactly the same issue with his Toyota Aygo after I did an engine swap....hence my advice!

Glad you got it fixed!


Irony - 28/7/18 at 09:28 PM

It happens to me all the time when starting from cold. Tickover when warmed up is perfect but from cold until it warms up my V8s tickover doesn't turn the alternator fast enough to generate power. So my alternator light flickers!


David Jenkins - 29/7/18 at 08:14 AM

I changed the pulley on the crank of my x-flow engine from the original pressed steel type to a machined solid steel one, as recommended in many books - unfortunately the solid steel one is a bit smaller (I think it's to prevent the alternator over-revving on racing engines) so the alternator light often stays on when I start the engine until I give the revs a blip, and flickers at tick-over.

I'd put the old pulley back (I don't rev my engine high) but the timing wheel is bolted to the front of it and I don't care to spend spend several hours resetting that after the change!


scudderfish - 29/7/18 at 04:50 PM

quote:
Originally posted by Irony
It happens to me all the time when starting from cold. Tickover when warmed up is perfect but from cold until it warms up my V8s tickover doesn't turn the alternator fast enough to generate power. So my alternator light flickers!


Mine does that but I find if I give the throttle a quick poke then it will go out and it will stay out even as the revs fall back.