Starter run on

[dieselsrule]

I know this topic is beaten to death, but..
Truck was running last year and just bought 2 new batteries. Fuel leaked back to tank while sitting so i was cranking it to bleed lines. Was going to do doghead relay but was waiting til i had new exhaust and tires and batteries(which i now have hence making sure it still ran). Starter relay stuck, so i shut off ignition and yanked relay wiring off(which i had hanging there for easy access) but starter continued to crank. Luckily i had just installed the batteries so wrench was laying inches away. This probably happened in less than 30 seconds, including initial crank time, until batteries were disconnected. The starter is new but i still took it out and bench tested it. As soon as i remove power from solenoid terminal it stops spinning like it should. I reinstalled it and even with ignition off , starter relay bypassed, and WIF sensor cathode anode thing removed it still cranks eternally when i jump purple and red starter relay wires for a second until batteries are unhooked. All my fusible links appear to be good. Can anyone help me narrow this down?

 

[dieselsrule]

Also the truck is an 86 m1008 with everything original as far as the 12v/24v hybrid setup with glow plug resistor, etc.. I read that even if the d/s alternator bit the dust i could still start the truck normally with fully charged batteries. I've looked at the wiring diagrams and can't see anywhere else the voltage to the solenoid could come from.

 

[sneekyeye]

It sounds like the solenoid on the starter itself is sticking. Those are generally pretty robust, but maybe yours took a poo poo on you.

 

[dieselsrule]

Even if it seemed to work fine out of the truck? The last time i tried it, i didn't have the one ground cable as tight as i should. The test light i had on the solenoid did flash on and off again when the starter spun a little but not enough to engage the flywheel. The next try, a few seconds later, it had a better connection and stayed on again. Should i just throw another solenoid at it in case it just didn't have enough amps to make it stick when i bench tested? I just used a 200 amp charger to check and the truck has two big commercial batteries, so there would be quite a difference.

 

[cucvrus]

If it were me. And it's NOT me or mine. I would eliminate the guess work and the rework time. I would take it to a competent rebuilder and have it thoroughly checked over. Beats the issues it can cause and the time it takes putting it on and off. may cost a few $$. But in the end it will give confidence. As always. Good strong load tested batteries are key to eliminate a lot of issues. This vehicle depends on good batteries and connections that are clean and tight. Just strong 12 volt batteries mean nothing. Good Strong cranking amps are key and load testing is a must do.

 

[nyoffroad]

Sounds like the starter solenoid to me too, possibly intermittent and it might test fine and be fine UNTIL it isn't! That will be when you don't have any tools with you or your by yourself out of cell service and it's -10* do yourself a favor and have it checked out by someone that knows what there doing NOT the auto zone type guys.