Starter motor issue

I forgot to add, the battery (Accu Varta 70Ah/630A) dates from March 2017.

As previously mentioned, charging it didn’t make a difference. I will try a jump start next.
2.5 years life would be disappointing but I’m afraid it is subject to many short runs and the occasional long one (I know, I know…) so I guess it would not be outrageous for it to have been run down – and trying to start it damp, the final straw.

Nick,

while it may make sense to test the battery to exclude one potential culprit I doubt the battery is the bad guy in this case. A poor battery may engage the starter, but not pull the engine, but it doesn’t make much sense to me that it turns over the starter, but the starter fails to engage …

Nevertheless, keep the faith

Jochen

75 XJ6L 4.2 auto (UK spec)

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To clarify, Nick; is the starter itself turning at all - and the engine?

As the solenoid clicks, drawing power, a contact at the end of the solenoid connects the starter directly to the starter itself - drawing heaps of power. A 0,6V drop indicates that the starter is not drawing any, or very little, current.

The main suspects are a failed/burnt solenoid connection - or failed starter brushes not connecting to the commutator. If the former; shorting the battery cable at the solenoid to the cable going from solenoid to the starter will crank the engine. If the latter; there will be no cranking…

Admittedly; a break in the starter wires may do the same - but an inernal short will draw very high current indeed.

(I know this is awkward - stated only for the record…:slight_smile:

A crude test; turning on the headlamp high beam and measuring voltage drop then, will be in the ballpark for solenoid current draw…

However; either fault require the starter removal…

Frank
xj6 85 Sov Europe (UK/NZ)
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from memory, they have a removable band to check the brushes, which can be R&R in situ

be annoying to pull it and find thats the issue

I had batteries fail on other cars and producing only a “clicking noise” while the rest seemed to work. The starter did not spin well and probably didn’t engage either. When jumping the battery does not help it is something else, but it is definitely the first thing to check.

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As the solenoid operates the pinion is forced against the starter ring gear, David. if it doesn’t mesh; a spring will allow the solenoid to ‘bottom’ - connecting starter to the battery. As the starter starts rotating, the spring will force the pinion into mesh…

If, usually due to tooth wear, the pinion wont’ mesh; there is a holy racket as the pinion hammers against the ring gear. Untrammelled by engine resistance, the starter will rotate at very high speed - even with some starter defects…

Frank
xj6 85 Sov Europe (UK/NZ)
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So the solenoid was weaker than the spring, so the starter never gets to turn because it never ’bottoms out’?
Am looking forward to what another battery does.

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That’s the general idea, David…

As usual; there are flies in the ointment. The solenoid pulls the one end of pivoting lever - the other, forked, end pushes the pinion assembly into the ring gear. If the lever assembly is broken, or disconnected either end, the solenoid may ‘bottom’ - powering the starter to run free…

One may concoct other ways too…?

Frank
xj6 85 Sov Europe (UK/NZ)
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I, on the other hand am looking to see what the following does, if attempted.

  1. Get all the battery connections clean and tight. the down under ground strap for sure…

  2. Again, down and under. apply power to the small spade and to the two large lugs. One on the solenoid and the other on the mtor itself.

Siidebar: My son has ancient forklift built on portions of a WWII Dodge weapons carrier. it has an updated starter. But, the flywheel teeth are battered. So, unless the engine fires almost immediately, the pinion on the starter is “kicked out”. …tolerated as removal of the transmission and the transfer case is a formidable task…

One would think the pinion should go first ???

Carl

Makes me wonder, too!
Clean connections better job than getting it all out for what was a bad connection.

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It usually does, Carl…

…but as it wears, it tends to hammer on the ring gear instead of slipping in quietly. (Actually, pinion and ring gear teeth often abuts at the initial contact - resulting in deformation over time). So at some stage both deforms to an extent that slipping occurs - resulting in rapid mutual wear…

As the engine tends to stop in either of three different positions, wear is concentrated to three smallish segment on the ring gear. At any initial signs of trouble; the pinion should be changed - which tends to delay further deterioration…

Incidentally; even if access is difficult, the ring gear teeth can be reworked in situ, with starter removed to some extent with a file - a laborious job, but not without some merit…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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ok, well jump start attempt made no difference. So it is pointing to the starter or starter solenoid.

The book makes changing this sound straightforward, but I’m thinking this is really a garage job…

thanks for all the advice.

Nick

If you have bad connections, anywhere in the circuits, a jump will not get it!!!

I was at the local market a few days ago. A fellow had the hood/bonnet up on a little Honda civic. Another fellow with a big white newer Jeep was seeking to hep with a pair of very long jump cables. No go, even with the Jeep revved up for more “juice”.

I deigned to have a look. Ugh, awful looking battery posts… Opined. both agreed. A few years ago, I would have opened a tool box and sawn to cleaning them. it was late and I exhausted. Not up to it. “do you have
auto Club?” "yes, and he hauled out his cell and began the call . I felt doubly sorry for him. the woman in the car was continually fussing as to the delay!!!

EXTRA: A recent similar issue with my Jaguar, Start systems similar. Jump did zip. Added ground cable from wing wall to engine, and it fired immediately !!!

Compeltion of a ground leg via the chassis fraught with issues…

Carl
Carl

Update / conclusion

Starter motor was burnt out. See picture below! My mechanic said it was a weedy low quality Chinese manufactured article and has replaced it with a superior one.

All good now. Thanks for all your counsel.

Nick
XJC 4.2 (1975)