Alrighty folks, I've about lost my mind today. Spent a few hours in the rain going through every electrical component in my truck today because I couldn't get it started in the BX parking lot, and am still lost. Would appreciate any ideas or input you might have because I'm out of ideas. Here is the background:

1997 F-250 HD 7.3, 180k miles, stick shift
Batteries replaced Jan 2019-- Interstate 1000Amps ea
Been hard starting in the cool mornings as of last week before glow plug job (hi 30s low 40s)
Recently replaced GP 2,3,and 4 with Motorcraft ZD-11
--all wiring and circuitry for glow plugs checks ok-- 1.8-2.0 ohms to each plug, 12.5v to each GP
Recently replaced Driver's side valve cover gasket due to electrically burnt plugin
Today truck started hard from work (high 40s today), drove 5 minutes to store and let it run for a few more minutes to make sure the batteries charged fine. It sat for 20 minutes and then on my first attempt to start it, I noted battery just below the Normal range, let the glow plugs warm it for 5 seconds past the wait to start light, then turned the key to start and engine turned hard to about 200 RPM and then faded off to barely turning (7 seconds or so of motoring). Second attempt battery is a little lower, but folowing the same procedure the motor barely (but definitely does) turn, maybe 50 RPM. I let it sit for a few minutes while I open the hood, check that cables are tight and nothing obvious is wrong. Third attempt same thing but a little slower happens and by the fourth attempt the battery appears to be nearly dead with the motor turning once extremely slowly before nothing. What I did from here:


Friendly fella with a Ram 1500 gas truck helped me charge the battery (2000 RPM from him for 10 minutes).
Attempted a start with slow turns similar to 2nd and 3rd try.
Took both batteries to local auto parts store and had them tested-- both batteries good and providing 1000A as specified on the label
Cleaned all battery posts and greased them
Cleaned starter motor electric connection and tightened solenoid
Tested live wire to solenoid-- 12.5 volts to solenoid from battery
Tried starting with hand on solenoid- good click from solenoid but now no turn from motor
Charged again for 20-25 minutes at 2000 RPM
Tried start- solenoid clicks but no turn from motor
Tried to jump across solenoid with a screw driver with key in ON, sparks but no reaction from starter motor.
Pull started it up behind the fella's truck and ran like a charm home for 10 minutes at high speed where I let it idle for another 5 to charge
Battery charge went up to normal range like usual after just a minute of driving
Put a screwdriver behind the alternator while idling and felt magnetic field (no increase in field at 2000 RPM but not sure if it should) so I expect the alternator is ok.
Turned truck off and tried to start immediately-- clicks and no starter engagement

I'm trying to think of what this could be but am at a loss with all the different indications here. I'm just a backyard mechanic, self taught and mostly working through restoring an antique-- not much for the newer vehicles and very limited electrical knowledge-- which I'm at the end of now. I apologize for the book on this-- any ideas from anyone would be much appreciated. Thank you!

 

Sorry to hear. Is your starter shot?

 

Is there a way to determine that without removing it and having it bench tested?

 

One more note would be that on the last start attempt I hooked a volt meter up to the battery, on attempting the start it went from 12.5 down to 11 volts. My Haynes manual isn't super clear on what this means.

 

It probably means the glow plugs are sucking juice.

Put in a SD high torque starter would be my guess for a cure.

 

I agree with Glen, your starter has given up the ghost. Install anew one and you will be amazed at how fast the engine will spin over.

 

The only other thing to try, is hook a jumper cable do the output of the relay, then hook it directly to the positive terminal on a battery. That would eliminate the relay itself as a possible problem. If it doesn’t try to start then the starter is dead. If it does start, the relay is junk. Usually if you can hear it click it is good.

if you do need a starter, there is a recent thread that goes over all the options. I chose the stock super duty gear reduction. It starts really fast and I can get one at any parts store if it craps out

 

We had similar issues, and it was the starter. When you put a new one in, SD/HT it'll bring a smile to your face when you hear how good it turns over. Night and day difference.

We got ours from Summit but there are a lot of places to go.

 

Thank you all for the input. Took the starter out and bench tested it... its toast for sure. Replacing it with a Motorcraft OBS starter on Monday-- I'll let y'all know how it goes!

 

The SD one works much, much better. Its high torque and amazing!

 

https://www.oreillyauto.com/detail/b...r+motor&pos=10

This is the one I got, they are giving it to me for $139 at the local O'Reilly's. Seems like it goes on both-- is this what you're talking about?

 

No thats just like the OBS ones and older super dutys, what you need is the High Torque version, it literally says it on the description when you buy them at the auto parts store, you just go to let them know.

 

Something like this
https://www.jegs.com/i/Powermaster/7...waAh19EALw_wcB

 

This is the one from oriellys. I use a 2001 SD as the search criteria to find the offset gear reduction unit

https://www.oreillyauto.com/detail/b...=Starter&pos=0

there are a couple of options available.

 

OK thank you, guess I should've read that other thread more carefully before ordering it. I'll run over to O'Reilly's and see if they have one of those available by tomorrow to switch my purchase.