Alternator woes

[CatmanDoes]

Well I've barely done 100 miles in my surf since I bought it and I've discovered the alternator appears not to be working... by discover I mean stuck in Tesco's car park

I had my multimeter in the car and the voltage was down too 11.97v - Even though the in-dash voltmeter was showing above the black line, in the "normal range" but that wasn't enough to crank the starter motor over enough to start it. When I finally got a jump start off someone I could see the voltage on the batteries was continuing to drop. Both batteries were giving exactly the same reading.

The battery warning light works ok, I see it come on before the engine - I was under the impression this would light up if the car was only running off the battery; which it appears to be doing, by the time I got home I was down to 10v. I got the charger on it now

I checked the 7.5amp charge fuse in the engine bay, that was fine. I really don't know as much about engines as I'd like to! Where should I start diagnosing the problem?

[Albannach]

Usually, but not always, when a Surf alternator fails, all the idiot lights come on on the dash.

You may have dodgy batteries.

Start the truck, put the main beam and heater on, rev the engine. If the lights brighten, it's probably the batteries. If they don't, it's probably the alternator.

[CatmanDoes]

Thanks for the prompt reply!

I had no warning lights at all. In fact 5 mins before I'd be driving down the road looked at all the gauges and said to the wife, "everything looks good".

The previous owner told me he'd had new batteries put in, they indeed look new.

Ok just jumped in, started her up. Stuck the heaters on full and put on main beam, rev'ed up and could see no change at all in the brightness of the lights.

[Albannach]

Most likely the alternator then, is the 100A fuse OK?

[BUSHWHACKER]

Make sure the battery terminals are clean and that the clamps are tight too.

[CatmanDoes]

Thanks for the input, it's cold dark and lashing it down out there at the moment so I'll what till the morning before trying everyone's suggestions

[Wolfracer]

Check voltage between alternator output (covered plug) and earth...

mine read 0V after ploughing through avalanche mud...




word of warning, surfs do NOT run if low on power from batteries, despite the myth that diesels don't need leccy power to run.

Auto box fails to change etc... engine won't rev, no forward motion, then it just, well, stops.

Trust me I know.

[BUSHWHACKER]

Check voltage between alternator output (covered plug) and earth...

word of warning, surfs do NOT run if low on power from batteries, despite the myth that diesels don't need leccy power to run.

Auto box fails to change etc... engine won't rev, no forward motion, then it just, well, stops.

Trust me I know.

Thats because they're EFI with ECT.

[CatmanDoes]

Well I couldn't go to bed without checking first, I dashed out.

All fuses in the engine bay ok, battery terminals are clean and the clamps are on there tight as a drum. I can see the alternator turning ok. I only just got in to see Wolfracer's post so I'll have look tomorrow, I think I know which covered plug you mean. Anyway that's a nice looking surf, I hope to get mine as muddy as that one day

Everything else is working on the vehicle... though quite often the speedo takes a few minutes before it starts giving me a reading - no idea if that could be related, probably not right? There did seem to be an odd *tick* noise as the engine ran, I couldn't determine the source though it did seem to come from the alternator area - I might video it tomorrow.

My old landy would run as long as it had leccy to keep the solenoid cut-off valve open. I'm glad the batteries held out to get us home, I had the wife and little one (17months) in the car with me.

[CatmanDoes]

ok started her up just now, the charger had gotten the batteries up to 13v. Checked the voltage from the covered plug on the alternator to part of the body and was getting 5.5v.

Took her for a quick run, came back and checked again, alternator giving out only 0.3v and the batteries down to 12.5v.

New alternator time?

[BUSHWHACKER]

Yup.
Or the cheaper option is to get yours reconditioned.
Don't run the batteries down too low too often or you'll need to replace those too. Keep them topped up with a mains charger.

[CatmanDoes]

Well just got back from a drive; I checked the voltage before going out and it was 12.35v. I wiggled some of the leads at the back of the alternator and started getting readings of 12.30v.

After a drive I had 12.18v on the batteries and only after a wiggle at the connector block, 12.13v off the alternator. It's weird I swear saw the voltmeter go up at one point.

The batteries are being topped up from the mains now, guess I need to find someone to fix it. How much does that sort of work cost (sorry that's a bit of a "how long is a piece of string" question)?

[gary-r]

it could be the small plug with 3 wires on the back of the alternator. thats the circuit that triggers the alternator.

mine was the same when i gave it a wiggle - went from 5.5v to 14.4v

one of the wires was broken right at the plug. its worth a try before shelling out on a new one

[CatmanDoes]

Bleh. I swapped out the alternator for a 2nd hand one (from TonyN) and it's still not charging, gah! I must have a broken wire or something - I swear I checked it all.

Oh well at least I got a spare alternator - lol

[Ambobeer]

Alternators do not generate anything, no matter how fast you spin them without being 'excited'.

You can try showing it a copy of Men Only but I doubt that will help either.

There needs to be a D.C. voltage going in to the altenator, this creates, if I remember right from college 30 years ago, the magnetic gubbins that allows it to generate. It generates A.C. which is then rectumfied into D.C.

Without the initial 'kick' you'll get nothing out of it. I think a good check of the wiring and plug are next on the checklist.