NEW starter motor machine gunning..

[legendgamesmaster]

Hi guys,

I got a new high torque starter motor from rough trax a few months ago. all has been fine until a few days ago, when it started to 'machine gun' on turn of the key. You know, rapid clicks like you get when the old one has bu88ered contacts.

anyhow, was wondering if anyone had any ideas - i doubt a NEW (not recon) SM would fail so quickly, so what are other causes of the machine gunning.

incidently, it DOES engage correctly after a few clicks - until today when it really did go mad.

So, heres a question related - whats doing the clicking? is it a relay in the dash, engine bay, or in the SM itself?

Anyone have a good article on how starter motors and the wiring to them works.


Oh, another thing i noticed today...
could be related...

when the key is in position 1, waiting for the plugs to warm up, I noticed my radio came on, clicked off, came on, clicked off.. several times, with a quiet click each time from in the dash somewhere.

again - any ideas - short circuit somewhere?


Barry at roughtrax is going to ask his contact at the starter motor firm what could cause this - neither of us think the starter is likely to be shot.

Any help - appreciated as usual.

Andy

[hiroler]

could it be a problem with the battery? sometimes when that is low the starter Motor ticks

[dsapsfo1]

Certainly sounds like the power dropping out somewhere, maybe when under load (high current). Have you checked all your earths? Particularly anything you may have disturbed when changing the starter motor. When it does turn over, does it sound clean and fast ie. does it sound like the battery is strong?

[legendgamesmaster]

the batteries are good

yes, when it does work, its instant startup, like you would expect.

I tried it this afternoon, and it went as follows:

MG = the machine gun clicks / ticks
SM = starter motor
R = Radio

I will document these 4 stages in each scenario:
1) turn key till glow plugs warm, (battery state)
2) Radio state (on or on-off-on-off-on-off)
3) turn fully to right to start, (result, time taken, battery state during turn)
4) release key (battery state)

1) normal; 2) R on; 3) MG, 2 seconds battery shows a bit low at this point, then SM kicks in, battery shows normal startup levels; 4) up to normal level.

1) normal; 2)R on; 3) MG 5 seconds - battery drops to very low then I chicken out and stop 4) battery normal

1) normal 2) R on; 3) MG 10 seconds, then all goes quiet, but i can hear a quiet 'whir' from somewhere in the engine bay, battery shows VVV low, interior light not visible. let go key 4) battery back to normal, interior lights back to normal

1) normal, 2) R on 3) SM fires first time, < a second to engage, no MG, battery all completely normal, 4) battery normal


tried again 20 times, all perfect.
the ONLY changes:
tried all the battery connections -they were ALL tight and good
added 40 l of bio, as tank was almost empty.

I wonder if its the relay that switches the SM on? is that IN the SM or a stand alone relay somewhere in the engine bay / dash????

Anyone know?

[Gamedawn]

Sounds like a poor connection somewhere, either in the main feed to the starter or on an earth cable. What you describe as machine gunning is typical behaviour when the solenoid has a low / marginal voltage going to it. The voltage is initially high enough to pull the solenoid in, but the current draw into the starter causes the voltage to drop so that the solenoid releases. Current draw drops, voltage goes up, solenoid pulls back in - repeat 'til battery dies. Could even be a battery failing (internally or a cracked terminal)

[lord lucan]

Sounds like a poor connection somewhere, either in the main feed to the starter or on an earth cable. What you describe as machine gunning is typical behaviour when the solenoid has a low / marginal voltage going to it. The voltage is initially high enough to pull the solenoid in, but the current draw into the starter causes the voltage to drop so that the solenoid releases. Current draw drops, voltage goes up, solenoid pulls back in - repeat 'til battery dies. Could even be a battery failing (internally or a cracked terminal)

def what he said, i couldnt put it better myself

[guysturg1]

you could try the earth cables from the batteries to the body, remove them and clean them as could hide a fault without you seeing it, the other thing to check its the feed from the battery to the fusebox under the bonnet as problem could lie there, but from how you describe what's happening it sounds like the battery failing internally, you could take it to a garage and put a drop tester on them which will show up a fault

[surfenstein]

have you got twin batteries fitted if so try swopping them around.

[LURCH]

I had this problem with 2 new starter motors from them, in the end got my original one reconditioned and as far as i know its still going, and that was from over 2 years ago. I think Barry sometimes gets some dodgy ones.

[mondo]

I had the same problem the other day except without the radio spazzing out. My battery was reading good voltage on a multimeter, but when i tried to start I had the exact symptoms you did. Tried putting it on jump leads, still nothing. Replaced the battery ( which was only 6 months old) and it now works fine! Couldnt understand why it wouldnt work with a jump lead, I know nothing about batteries or electrics, but it seemed that although the battery had a good voltage, there was too much resistance in the battery to turn the engine over, and consequently, when hooked up to jump leads, too much resistance for the power to pass through the battery and into the SM.
I could be very wrong, but its best to start with the blindingly obvious and change your battery over.

[legendgamesmaster]

thanks one and all

The description of how the starter 'machine guns' is very useful. thanks. OK, so it seems I will have to take the batteries to Halfrauds, where I purchased them less than a year ago, for testing.

Many thanks.

Incidently, I fiddled with the terminals, and found nothing loose / adrift etc. No corrosion (hey now, hey now na-now now.... ) or anything that would suggest a problem there, BUT it works fine again now, so I guess an internal fault might be on the cards.

Finally, where is the solenoid that is actually making the sound?? Anyone know? and the Relay, wheres that then?

Cheers all.