Does this sound like the alternator? FIXED!!!!!

Post by **NafemanNathan** » Mon Oct 05, 2015 7:19 pm

This quite often happens with my 5th gen, but when slowing to a halt my revs drop right down and the car almost stalls or sometimes even does.

It happened today after driving for 15 minutes at reasonable speeds, then stopping for almost an hour, then driving for 5 minutes reaching 30mph max to get petrol, to then drive for 5 minutes to get home. It was on the leg home that it completely cut out twice!... Once on approaching a roundabout and once when joining stopped traffic.

When I pulled up at home I tested the dropping revs with and without the blowers on and the rear window heater. Both had been on when it cutout. I'd rev to near 3000rpm then lift my foot off. It was evident that with the rear window heater the revs were dropping a lot lower than without it on. Probably to about 500rpm. The blowers would reduce it further and so with braking on top of that I think is when it's cutting out.

Do you think this could be alternator/battery related?

If I leave the car to warm up for longer before driving off it reduces the likelihood of this happening. It's definitely worse with frequent stop starting as well.

Also I left my lights on at work the other day (my warning buzzer has disappeared. It's on the list). It had only been 1 hour 45, but it was still enough to not be able to turn the engine over. Does that sound about right or did that drain too quick?

Ted · Post by **Ted** » Mon Oct 05, 2015 7:24 pm

Sidelights or headlights

Post by **vanzep** » Mon Oct 05, 2015 7:28 pm

If you have a multimeter you could check output from the alternator

Post by **ek9sid** » Mon Oct 05, 2015 7:30 pm

I dunno about the first bit as I've never come across anything like that in my years of driving/messing with cars.

As for the lights left on, to put it into perspective, I left the lights (side) on my micra when I first passed my test whilst I had Sunday sinner at the parents. Came to it roughly 3 hours later and it still started. Now I know the micra is a completely different box of frogs to the prelude but I just thought I'd give you my experience. Not tried it in my 5g yet though.

Post by **NafemanNathan** » Mon Oct 05, 2015 7:36 pm

Ted wrote:Sidelights or headlights

Headlights

Post by **vanzep** » Mon Oct 05, 2015 7:38 pm

Im thinking alternator on its way out so not charging battery properly.
@newkid should have a spare alternator if you need one sharpish

the alternator should produce around 14.2v (thats the figure for 4th Gens but 5th should be same/similar)

last time i had a problem like this it was just the big connector on the alternator had not been clipped into place properly so you could check that easy peasy

Post by **NafemanNathan** » Mon Oct 05, 2015 7:42 pm

vanzep wrote:If you have a multimeter you could check output from the alternator

I'll do that when I get a chance. How many volts am I looking for, 14?

Edit: Cheers Nick

Post by **vanzep** » Mon Oct 05, 2015 7:44 pm

no worries nafe - should be an easy fix either way

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Mon Oct 05, 2015 8:02 pm

NafemanNathan wrote:
Ted wrote:Sidelights or headlights
Headlights

1:45 running headlights is a long time! Nothing there to suggest anything at all wrong with your battery...

Post by **RattyMcClelland** » Mon Oct 05, 2015 8:04 pm

Mine does similar but never stalls.

Revs drop to an almost stall and battery light and oil come on for a split second.

Mine has only ever done it since installing the innovative engine mounts.