Ford Power Stroke

[Jackman]

Saw the Mustang thread so what the heck I'll try too with my truck issue.

I have a 1997 F-250 Power Stroke hasn't run in 4 years but ran fine when parked but it did need glow plugs, any way I put in new glow plugs/harnesses and a GP relay along with the starter relay, used two fairly new batteries that are deep cycle marine that I charged up on a regular charger and they passed volt and load test , I turn key starter does not turn, return key to off position and batteries start to boil , I quickly disconnect them check all my work it appears correct yet still my batteries will boil.............. I don't know I think the truck is correct but maybe I wrecked the deep cycle batteries by charging them with a standard charger. Also I tested the starter on the bench it works fine I did put a cheap auto zone solenoid on it.

I've done GP's several times before and this is my 3rd Ford diesel so I'm kind of up on theses things I think but deep cycle batteries are new to me

Any thoughts?

[tst]

sure the battery cables are hooked up correctly ?

[Jackman]

Yup that was the first thought but the boiling batteries doesn't occur until I turn the key on and doesn't stop when key turned off , only stops after I pull the cables. I've bypassed the GP system and the problem remains, checked and double checked the starter relay wiring (all good) next I'm going to get a Ford Motorcraft relay and give that a try , I would think the problem is in the relay or the starter since it doesn't happen until I turn the key..

[outdoors4evr]

Don't trust the wiring colors. A red cable might be the ground. Follow each wire to its destination to verify the right post is being used.
My best guess would be a bad starter and a sticking starter solenoid. Check for wires near the starter that could be touching a ground.
The new solenoid probably sticks closed and the starter may have a short inside the case.

Did you verify the engine is not locked up? Make sure the crankshaft turns (by hand) 360 degrees without binding.

Maybe a wiring "redesign" by mice during the 4 years of rest. Look for wires with missing insulation.

Separate issue: A deep cycle battery is not meant to start a vehicle. Deep cycle batteries are designed to provide smaller amounts of current for long periods of time. They don't really have the surface area in the acid to provide lots of amperage like a starter would require. A deep cycle battery would have a short life in this application.

[Jackman]

Did you verify the engine is not locked up? Make sure the crankshaft turns (by hand) 360 degrees

No , but what a scary thought, going to check further but I doubt it’s locked up.

Also going to dig deeper into the starter and starter relay , hope it’s the cheap auto zone relay I put in .