starter tempermental

[blueute]

Starter works perfect but on the occasional day decides not to. All I hear is the solenoid pushing the cog ("click") in but the starter fails... then turn again and it works perfectly. has new battery and new alt. just put in new starter brushes 3 weeks prior and only now showing problems.
where do I start looking ??
If anyone can help I would greatly appreciate it
cheers

 

[Champo24]

Contact at the back of the starter motor could be worn, dirty or just sticking, maybe try an electrical contact cleaner even wd40, otherwise a starter rebuild or check your battery out put?

 

[blueute]

thanks for that, will have a look now, if I dont see anything , going to pull it out and check it.

 

[Old.Tony]

It could be the solenoid, which is little more than a metal bar that is dragged against two posts to carry high DC current. The contact points can arc and get carbon scoring, which inhibits power flow. While you're digging around there, check the earth lead on the engine (remove, clean, replace).

 

[blueute]

just got it out and look ok Doesn't have any bad burnt out smell, and the bench test confirms that the solenoid is working ok but no armature movement, ?? how do you test that?? I have the + from jumper to the + post on the starter, the - jumper to the vice it clamped in and I have a spade plug and wire to a spade post next to the others on the starter. short that to the + should spin it?

Update: Stripped it completely down and checked for scorching and tested the circuits with the help of
http://www.autozone.com/autozone/re...nspect&pageId= 0996b43f80a0140d&subtitle=test
http://www.groschopp.com/how-to-check-a-motor-armature/
and
http://www.gonefcon.com/trucktcom/starters.htm#qc
OK , the Nissan D21 is not a truck but the link above helped at 1 in the morning.
1 thing I did notice was a special lock washer I had bought to make double sure that the main earth strap to the starter didn't come loose again, was actually non conductive also the eye of that lead was excessively large which could have resulted in very little surface area contact. so I beefed up washers and filed all surfaces of connectors.
NB the starter comes out topside best, just got to disconnect dipstick and swing out if way and taking battery out gave more space too.
Result has been 100% so far. (shouldn't happen again as I have threatened it with a chinese replacement)

 

[Old.Tony]

I had to approve the post for the links, that issue will go away after you post a little more.

So it's working now? Poor electrical contacts? Make sure you grab some of that blue stuff they spray on battery terminals and give the things a squirt. It should slow down oxidisation/corrosion from creating the problem again.