Was doing a compression test today and found cranking speed varied a bit with glow plugs out. Sometimes cranked slower (not real slow, but comparable to when normally starting it) and other times cranked pretty fast like I'd expect only making compression on one cylinder. Made it difficult to get accurate readings. Under 1 yr old group 31s with new 2/0 grounds and between batteries and 3/0 to starter. Started is unknown age and been doused in coolant at least twice from block heater issues. Is it time for a starter?
Cranking speed inconsistent
- Thread starter dunk
- Start date
ironworker40
NYC Ironworker
I would clean all connections and re-check. I'm assuming you have the grounds going to the proper spot on the front of the block with the smaller wire on the one going to frame. Also charge and load test batteries separately. I think then you can narrow it down to the starter.
Thought I'd post a resolution for posterity. Starter called it quits some time after I posted this. Click from solenoid on fender (not sure if solenoid at starter was working, but both wires were clean and tight), but no crank. Installed a new Powermaster 9050 starter and couldn't be happier with it's performance. For half a dozen starts so far it cranks faster and starts quicker.
icanfixall
Official GMM hand model
Was about to suggest your starter was dieing but you seem to have figured that out and replaced it. So all is good.. Nothing like a nice new or rebilts starter cranking fast.. Funny how quickly these engines fire when they spin fast.
Mine is doing same. Hope it will wait until warm weekend, another DB going back in.
ironworker40
NYC Ironworker
CHECK AND CLEAN ALL YOUR CABLES REGULARLY. This includes grounds to block and positive on the starter, not just the battery connections. Dirty connections and low battery voltage eats up solenoids and stater motors..
The biggest trouble with starters is the main bronze bearing in the front by the gear. The bearing is surrounded by felt which is soaked in oil, after all the oil has leached thru the bearing, the bearing wears pretty fast, there is one hell'va magnetic force pulling the armature towards the poles, then it begins to scrub the poles, when that happens the starter speed (RPM) slows down considerably, then it starts to pull really high current. So if the cable connections, cable and or batteries are not up to par, you know what happens then.
The brushes are copper impregnated and take a long time too wear out.
The brushes are copper impregnated and take a long time too wear out.
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