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+--- Thread: Random No Crank's (W123) (/showthread.php?tid=4429)
Random No Crank's (W123) - Kozuka - 03-19-2013
So, I've been having this problem recently (actually for awhile). Basically is that sometimes, it won't crank. Not just in the morning after sitting overnight, I'll drive turn it off go for 5 minutes then it wont crank after idling for at least 10 minutes. Sometimes I'll bump the key twice and it will start, others I could sit there all day bumping the starter & nothing. Sometimes if it is left for awhile and I come back, it will crank. Normally, I'll just push start the wagon by myself. Which is fun.
All lights turn on including the glow plug relay cycle every time, there is obviously a power drain when I'm in the cranking position since the dash lights dim. Last time I checked Alternator was putting out 13.95V, Starter is a reman bosch unit that's less a year old. Connection from battery to the starter is tight, so is the body ground from the bell housing. Every time I turn the starter into the cranking position it clicks. Battery is also new.
Basically I'm at the point where I'm going to redo all the main power & ground wiring and replace the alternator. Unless you guys can point out something I'm missing.
RE: Random No Crank's (W123) - Simpler=Better - 03-19-2013
Assuming all your connections are tight....
Can you hear the solenoid click? If not, that's your problem. If it clicks but doesn't spin it's the brushes and or bearings in the starter
You can rebuild it for around $20 and takes about an hour (mostly cleaning the gunk).
RE: Random No Crank's (W123) - raysorenson - 03-19-2013
Are you familiar with how to do a voltage drop test?
RE: Random No Crank's (W123) - Kozuka - 03-20-2013
So while key is in the cranking position have the voltmeter on the positive terminal of the starter and the ground on the battery ground post and it should read a drop of less than 0.60v while key is in the cranking position from the battery voltage if the wire is ok? This shows how much resistance I'm getting from the wire to the starter? Can't say I've ever done one, but I'm pretty confident with a multi-meter and direct current electrical stuff. It is entirely possible that one of the wires got fried increasing the resistance.
RE: Random No Crank's (W123) - Druk - 03-20-2013
My take is that the main copper contacts in the solenoid are burnt. You can still get a 'click' but the erosion on the contacts stops current flowing.
This video illustrates the problem well and although it's for a Denso starter and the basic design is different the theory is identical.
http://www.nationsautoelectric.com/densoparts.html
.
RE: Random No Crank's (W123) - raysorenson - 03-20-2013
Druk's probably right.
Voltage drop is done across the negative side or across the positive side. There shouldn't be any voltage between the negative battery terminal and the negative batt cable, engine or body. If there's a voltage drop though, there will be. Voltage drop is measured with the load present. Were there a voltage drop across one of the battery cables, your dash lights would be going out. I'd just check for a voltage drop from the batt negative terminal to the starter housing and a drop from the B+ terminal to the + terminal on the starter. If there's no voltage present while the no-crank is present and the key is in the start position then there's no voltage drop and you just make sure the relay is working. Once all that's eliminated put another starter on. :-)
RE: Random No Crank's (W123) - Kozuka - 03-24-2013
Why is it that I can sit there and turn off and start maybe 3-4 times after running and have no problems. Seems really like I have some sort of power drain but after sitting overnight it will start. Replaced the alternator, it was old and full of crud anyway. Still no dice. Need to go buy another multi-meter, mine always seems to go missing after I fix someone else's stuff with it. One time it was a fluke.
I'm going to buy some wire and relocate the battery anyway but I'll keep you guys updated, I think I still have an old starter kicking around somewhere that worked.
RE: Random No Crank's (W123) - Simpler=Better - 03-25-2013
It sounds like something is worn/dirty/flat/possessed. If you have a spare starter, throw in brushes and clean it they're only $15. THEN put that badboy in
RE: Random No Crank's (W123) - willbhere4u - 03-25-2013
Starters can be heat sensitive when the contacts are worn out. and can makes a better contact when cold than hot.
RE: Random No Crank's (W123) - Kozuka - 03-30-2013
FYI, you guys are right about the starter. I relocated the battery with thick welding wire & same result I'm still going to replace the engine ground with the same stuff but I'm done for today, strong cranking when it does work. Guess, I'm either going to rip apart this starter & clean it or see if I have another in storage to rip into.. Found my multi-meter but need some AAA battery's. Anybody know where the diy is to rebuild these starters, I looked on google and mostly just saw guides to take them apart and what needs cleaning/lubing. Source for parts if needed, guess it didn't like getting rained on a few times while I was getting everything together during the rebuild, worked for a year without issue but it seems like it's beyond warrenty.