Starting problem after alternator swap

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keithlard

keithlard

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63
Location
London
I put a new (70A) alternator in the car and tried starting it. The starter turns, but the engine doesn't crank - there's just a high-speed clicking noise.

I wondered if the battery was too flat to turn the engine, so I jump-started it. Same result.

I then wondered if the alternator belt was too tight, so I loosened it off a bit. Same result. The alternator spins freely when it's off the car, and the pulleys are lined up properly and the belt is more or less at the right tension, so I'm not sure what's wrong.

I rocked it back and forth in gear a bit just to make sure that nothing was jammed, but it hasn't made any difference.

I'm puzzled as it was starting and running just fine before the swap, and I've touched nothing else except to take the turbo pipes and air box off to get at the alternator.

:confused:
 
Sounds like it may be the starter motor pinion not flying out properly and engaging to turn over the engine - either that or a broken tooth

Try giving the starter a good whack with a hammer (seriously).

If that doesn't fix - starter motor removal I'm afraid. Suspect a freak coincidence, although the starter motor and alternator are in the same sort of area.

That said, if the starter motor is just clicking (rather than making a whirring sound) you may have dislodged one of the wires

I could be wrong, so beyond the whacking the starter and checking the wires are all secure, you might want to wait for some more advice before strip down.
 
Station House said:
Sounds like it may be the starter motor pinion not flying out properly and engaging to turn over the engine - either that or a broken tooth
I could be wrong, so beyond the whacking the starter and checking the wires are all secure, you might want to wait for some more advice before strip down.
Click to expand...

Thanks for that. Today's mission will be to check the wiring (since I can hear the solenoid working, it's possible there could be no current to the starter motor itself) and see if I can move the car in gear to make sure that the engine turns freely and I haven't dropped a spanner in there or something.

If that doesn't turn up anything then I am going to start suspecting coincidences!
 
When you turn the ignition and you hear the solonoid click, is the starter motor actually turning over but not turning the engine, or just clicking?

If just clicking could be:

- wiring
- poor earths
- failed solonoid

If the starter is actually turning but not turning the engine:

- starter motor pinion
- broken tooth (but moving the Landy with gears engaged should get you to a non broken tooth to proove or disprove)


Sure others will have suggestions to help
 
Station House said:
When you turn the ignition and you hear the solonoid click, is the starter motor actually turning over but not turning the engine, or just clicking?
Click to expand...

It's going clickclickclickclickclickclickclick...

The engine did turn over once or twice, briefly, when I first tried it, and I could see that the alternator belt had moved because I marked it. But now, nothing, which makes me lean towards electrical issues rather than a mechanical failure - I think it's rare enough for a starter to just suddenly give up the ghost with no warning, and too much of a coincidence that it was working perfectly until I changed an electrical part on the engine.
 
if starter solenoid just clicks its either to flat battery ,poor contacts, jumping flat battery doesnt allways give enough left after going thru flat battery to start engine
 
As James says, check the battery - I had a similar problem and it turned out to be the battery ( duff cell, battery replaced under warranty)
 
IGP50 said:
As James says, check the battery - I had a similar problem and it turned out to be the battery ( duff cell, battery replaced under warranty)
Click to expand...

I tried it again with a charged battery and not only did it not work, it immediately flattened the battery! So I'm pretty sure there's a short somewhere - if the alternator B+ connection is shorting to earth, that would probably explain it.

I had to cut the plug off the old alternator and replace it with ring connectors, so I'll take it off again and have a look...
 
slight hijack... is there any money in alternators than need new bearings..? i have a nackred one on my 200tdi engine, so will put my td one on, just seems a waste to throw it away!
 
keithlard said:
I had to cut the plug off the old alternator and replace it with ring connectors, so I'll take it off again and have a look...
Click to expand...

Well, I did that - everything looks OK with the wiring, I can't see any obvious shorts or signs of burning or damage. The only thing I'm not sure about is the connections to the alternator. There were three wires on the old one: two thick brown ones and a thin brown and yellow one. I'm assuming that the thick ones are B+ and the thin one D+, so I'm guessing that it should be connected like this:

alternator.jpg


But with no markings on the alternator itself, it's a bit difficult to tell. It is a Global Power brand RTC5680N.

All the wiring to the starter looks fine - it's massive and unshiftable.

I'm really getting very puzzled about this. It certainly looks as if the alternator is shorting the battery to earth somehow, but I can't figure it out. When I turn the key I hear the starter relay and solenoid clicking very fast, but nothing else, and it drains the battery quite a bit. All the fuses are intact. I've tried with a freshly charged battery just to make sure and it's exactly the same.

Would it hurt to try and start it without the alternator and drive belt in place? If that worked, I could at least say that the alternator is definitely the problem.

On another tack, would it help to measure resistances across the alternator terminals to see if something is internally shorted? I read about 2200 ohms between B+ and ground but I don't know if that's normal or not.
 
keithlard said:
Well, I did that - everything looks OK with the wiring, I can't see any obvious shorts or signs of burning or damage.
Click to expand...

I just had another check with the meter across the battery, and when you turn the key, the voltage drops to about 8/9 volts. So it looks like current is reaching the starter, but it's just not doing anything!
 
i think its down by the exhaust down pipe..? not sure where best access is, only ever got to one with the engine out!
 
Yep, lay underneath crawling behind the passenger side front wheel and look up - it is a bit hard to reach!

Disconnecting the alternator and starting will cause no harm - red ignition light will just stay on - good idea to see if the wiring or alternator has a fault
 
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