Starter issue

[Dvine]

Oh and RonD I'm getting 25mpg average. Before exhaust replacement I was getting like 12

 

[RonD]

OK lets do this step by step

Picture of starter motor, with relay/solenoid: https://www.idmsvcs.com/2vmod/starter/solenoidspadeterminal/PICT6197.jpg

The larger post labelled B in the picture connects directly to Battery Positive
This can be connected to battery positive at the inner fender starter relay, by both cables being on the same larger post

Picture of starter relay(often mispronounced as starter solenoid, lol): https://i.pinimg.com/736x/8d/b0/f8/8db0f8f2bc09fb31756648c36b8404b4.jpg

One of the larger posts has several wires, thats the Battery positive post, doesn't matter which one, as long as all those wires are on that one post
And one of the wires is battery positive and another is wire to the large B post on starter, if you think this cable to B is bad then replace it

Battery positive terminal-----large cable-------starter relay post---------larger cable-------------starter motor B post

That's the wiring for "spinning" the starter, this hook up needs to pass 65 amps so if it doubt replace the larger cable, both if you feel its needed


Activating the starter motor
In the starter relay picture its labelled "trigger" and has a green line, its a red/blue stripe wire
This wire has 12v with key turned to START
IF..........this relay is grounded(base screwed to metal inner fender) then when key is turned to START this relay should "click" closed(trans needs to be in Park or clutch pedal down)

When relay "clicks" closed the TWO larger posts are now connected together inside the relay
One post is battery positive(12v), so now the other post has 12v as well
The other post just has one smaller wire connected, the small red one in the picture
This smaller wire runs down to starter motors "S" post low current trigger, small post
When the "S" post gets the 12v it activates the solenoid that move the starter gear out AND it connects the two larger posts together which cause motor to spin

If the motor doesn't spin then its not connected to battery positive, so bad cable or bad relay part inside the relay/solenoid

This is a hybrid system only used for a few years
The smaller "trigger" wire on inner fender relay was extended and connected directly to the starter motors "S" post, bypassing the inner fender relay
The relay was there for several years because that one larger post with battery positive cable is the 12v distribution post for the whole vehicle
These extra wires on that post are for alternator and engine fuse box, ALL 12volt power comes from that one post

 

[Uncle Gump]

Sure sounds like the solenoid on the starter is bad. I know you say it works during bench testing... but it isn't working under load.

GM has used this type of solenoid forever. There is a contact internally in the solenoid that connects the path for power to reach the armature brushes. They do this because you can't start spinning the gear before the gear is engaged on the flywheel/flexplate. So the first action of the solenoid is to drive the gear to the flywheel. Once there... contacts allow power to the armature.

 

[Dvine]

Sure sounds like the solenoid on the starter is bad. I know you say it works during bench testing... but it isn't working under load.

GM has used this type of solenoid forever. There is a contact internally in the solenoid that connects the path for power to reach the armature brushes. They do this because you can't start spinning the gear before the gear is engaged on the flywheel/flexplate. So the first action of the solenoid is to drive the gear to the flywheel. Once there... contacts allow power to the armature.

Since it will kick out and spin with no load, doesn't that mean the parts inside the solinoid are fine? Or it's broke just enough to work without a load but not under one? Interesting. I'm with ya on it being the starter solinoid since I can't find anything else it could be. Once I can replace the starter, again I'll let you guys know if it works. I've tried 3 (2 donors) but maybe they were all bad too. Thanks to everyone having patients with me. I don't call myself a mechanic, but I can make things better than they were.
Side note: if you try grounding the frame and firewall from the same place as your block to firewall, witch for me is the same ground used by wiper motor, it'll fry you're wipers....

 

[Uncle Gump]

The starter draws less current freewheeling then it does loaded. Any resistance there (poor contact) could cause it not to spin when loaded. When you use your jumper you bypass the resistance and it works.

It's kinda the only thing that makes sense to me.

 

[alwaysFlOoReD]

Could the "bendix" be pooched. On the old ford starters with an "over running clutch drive" the inside rollers or ramp can get screwed up so that it wont spin the flywheel even if its engaged.

 

[Dvine]

Could the "bendix" be pooched. On the old ford starters with an "over running clutch drive" the inside rollers or ramp can get screwed up so that it wont spin the flywheel even if its engaged.

Haven't heard of that before. It's just so odd that there's no other issues with this truck. If it's not the starter solenoid, I would think there's other things that would be wrong. As I said, I'm just going to replace the whole unit (again) and see if thet works

 

[Dvine]

So here's the closure of this thread. I wanted to tow a car around and needed the ranger battery so the car would have power steering and truck died. Grabbed the exploder alternator and the key has worked just fine for over 2000 miles. Thanks to everyone, couldn't have driven my ranger this far without you guys. Next post: tranny rebuild or replace?