- Thread starter aesmith
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Right after some other distraction I got back on this. Starter refitted and works perfectly, as it has always done immediately after being refitted. So I'm back where I was however many years ago.
Unless there are any other suggestions I don’t think there's anything further I can try or test until next time it plays up. When it does so I intend to ..
(a) Measure voltage at the solenoid terminal when it should be trying to start
(b) Try a jump lead direct from battery +ve to solenoid terminal, bypassing all wiring etc
Although it sounds silly to ask advice and then ignore it, I really can't understand the relevance of cranking current, which of course I can only measure when the fault's not present. When it's working it turns over smartly enough. When it doesn't it's not even trying to crank.
Unless there are any other suggestions I don’t think there's anything further I can try or test until next time it plays up. When it does so I intend to ..
(a) Measure voltage at the solenoid terminal when it should be trying to start
(b) Try a jump lead direct from battery +ve to solenoid terminal, bypassing all wiring etc
Although it sounds silly to ask advice and then ignore it, I really can't understand the relevance of cranking current, which of course I can only measure when the fault's not present. When it's working it turns over smartly enough. When it doesn't it's not even trying to crank.
Jack_K
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Cranking current can identify a poor connection (low current), faulty starter (high current) or mechanical fault (high current). It's not necessary but it gives good insight into the condition of everything. If the reading is out of standard range then you'll be more likely to have issues even if it works most of the time.
dobbslc
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Looking at the engine casting and it's very grubby / rusty, it would be worth cleaning that and the starter back to clean metal so you know the ground is good.
As suggested, setting the meter to a fixed range helps. Cold start it showed just over 10V when first cranking, dropping to just under 10 after a couple of seconds. Normally it starts in much less than a second, the test was done without using glowplugs to make sure it didn't start before I got a reading.
I measured from the +ve terminal on the body of the starter, with -ve lead clipped to the starter body.
Jack_K
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That sounds like it could be a bit low as I'm guessing it would drop below 9.6v after 15 seconds (standard test time). Without further testing, it could be a lead, connection, the starter or the battery.
Without a current clamp the next test is to check for voltage drop between the battery posts and the starter case/positive terminal when cranking. Batt + to Starter + and Batt - to starter case. Above 0.5v is bad.
You could also check the voltage at the battery posts when cranking but I don't think this is your problem.
Measurements this morning. Cold start (around 4°C) if that's relevant.
Battery +ve to starter +ve terminal 0.13V
Battery -ve to starter body 0.32V
I don't think I've ever in my life run a starter motor for 15 seconds.
Jack_K
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Looks good. Maybe the earth could be improved but it should work fine.
I've used the digger a few times now with no issues. Then today I shut off for five or ten minutes mid job, and it wouldn't start. Normal symptoms, no noise or response from starter or solenoid.
I was at the bottom of the field so not well placed for tests etc. However it started up right away with a jump lead from battery to the solenoid terminal. So it looks like voltage at the solenoid may be the issue. Why it cropped up after a brief stop when the battery would be at full voltage, but not on cold start first thing, is a mystery. Also why does it only affect this starter and not either of the two crap replacements.
I was at the bottom of the field so not well placed for tests etc. However it started up right away with a jump lead from battery to the solenoid terminal. So it looks like voltage at the solenoid may be the issue. Why it cropped up after a brief stop when the battery would be at full voltage, but not on cold start first thing, is a mystery. Also why does it only affect this starter and not either of the two crap replacements.
Barking Mat
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What diameter of wire goes to the excitation on the starter motor ?
We had issues with this when hot.
addjunkie
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Probably corroded at the crimps too
Barking Mat
Cuddler of hedgehogs.
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What we did before we rewired the loom, was stick a 1.5mm wire from bat +ve via a push button directly to starter excitation terminal, no more issues.
Eventually we found the shockingly thin wire was only between the engine loom last plug to starter, the rest was well specced.
Kubota 1.5L, 4 cylinder diesel, not even original Kubota loom.
