Starter blowing fuses.

[Squibbly]

The slo-blo fuse is interesting. I've never seen those before. The wire that feeds 24v to the starter relay dose originate from a fusible link at the junction block. Maybe it was a bad idea adding another fuse just before the relay. But.... before I pulled the starter I ran a jumper straight from the battery post to the starter solenoid. Originally I had an inline fuse in the jumper. Once it blew I cut the fuse out & touched the unfused wire to the battery post quickly. It arced & stuck to post instantly. The solenoid clicked but the starter didn't spin the engine over. I did all this w/the ignition wire from the truck disconnected. I'll try the jumper cables thing soon as I get a chance. That's a good idea.

Using the jumper cables should tell you if your battery cables have an issue.
I can tell you that when I first bought my truck, the *ground* cable was smoking it got so hot trying to start the truck. I looked at the cable attached to the battery and there was corrosion in the clamp. I took it apart and cleaned it with a steel brush and some electrical contact cleaner and put it back together. Tried to start, now the red cable coming from battery 1 to battery 2 was hot and smoking. Again, looked at the clamp...corrosion. Took it apart and cleaned it. No more issues (well with heat...it was a multitude of issues causing the hard start, the least of which was 8 bad glow plugs, loose starter with the bracket disconnected, and bad flex plate).

You have to have a clean ground from the engine to the body as well.

All of these things will cause resistance which will generate heat, hence a fusible link in the circuit which is a heat-based "fuse" and not specific amps.

One last thing...those *are* 24V solenoids, correct? Do you have a part number?

 

[sgms18]

NSN 2920013537036

I just re-tested both starters w/jumper cables connecting the batteries & got the same result. Solenoid engages for just a second & trips the circuit breaker in my Power Probe.

 

[Squibbly]

NSN 2920013537036

I just re-tested both starters w/jumper cables connecting the batteries & got the same result. Solenoid engages for just a second & trips the circuit breaker in my Power Probe.

When I tested mine, I hooked the ground up to the post the bracket connects to.

I then usually get a long screwdriver and clamp the positive cable to it so I can test these positions individually and be able to jump (a.k.a. connect) two posts together.

You probably already know this, but for people who may read this later and don't know.



Edit: I feel like I need to add a disclaimer here that you *are* dealing with 24 volts here. If all you are looking to do is make sure the bendix shoots and motor spins, just hook your cables up to the positive and negative of battery #1 (Just 12V) to probe these connections. If you do the full 24 volts you will get a large spark, and if you are "timid" about doing this and don't make a good solid connection with the expectation that this large 24 volt motor is going to spin and isn't connected to anything to keep it stable you will get a welding arc that will potentially scorch your nuts or bolts.

Make a 24 Volt push button test switch (and strap the starter down) if you want to be safe-er-er..
In fact this just gave me an idea for a new video...

 

[Squibbly]

NSN 2920013537036

I just re-tested both starters w/jumper cables connecting the batteries & got the same result. Solenoid engages for just a second & trips the circuit breaker in my Power Probe.

I don't have a powerprobe. Let me check with my brother @Rocknus. He has a power probe and might have some insight into whether or not they are capable of handling the draw from one of these.

In the meantime:
Solenoid Testing 101 - YouTube

 

[Squibbly]

I don't have a powerprobe. Let me check with my brother @Rocknus. He has a power probe and might have some insight into whether or not they are capable of handling the draw from one of these.

In the meantime:
Solenoid Testing 101 - YouTube

I checked with him, and his powerprobe is only good for 8 amps.

 

[sgms18]

Well that's not good. I was sure it was 30 but I've been wrong before. Still though I ran a jumper from solenoid to the battery with the starter still on the truck & the ignition wire disconnected & it was blowing 30a fuses & then a jumper w/no fuse & it would arc, stick & start heating up. The battery cables look good. Tight, no corrosion. The engine/body grounds are tight. I reckon I'll take em loose & clean for good measure. I just put 2 group 31 Interstate remans in the truck. Going to load test them anyhow. Man I appreciate all the responses. I still feel like I'm going in circles. Checking the same stuff over & over but there's only so many parts to the system. Especially using the jumper wire.

 

[Barrman]

A power probe won't push the starter or solenoid to work. They aren't made for that kind of a load.

It will let you test the power to the big stud and if the purple wire on the small S terminal is getting power to the solenoid when the key is put into the start position. That is the kind of thing they are made for.

If both of those have power at the proper time then it is pretty clear the starter and or solenoid is the problem and then needs to be removed and tested off the truck.

If the problem is the 24 volt big wire then the Buss bar on the firewall by the fuel filter is the other end of that wire and you get to check there.

No start signal gets you checking the wire to the firewall thru plug over behind the fuse panel on the drivers side firewall. I would suggest pulling that apart anyway just to check for good connections and no cross arcing of contacts. The path then goes to the starter relay and finally the starter switch on the steering column.

 

[sgms18]

Well I believe the truck is fixed. Only thing I can figure is it had 2 problems, one hiding the other. Let me try to explain how this whole deal played out. When all this started I had a fairly new DB electrical starter on the truck & a new old stock CME Arma starter on the shelf. When the truck first started blowing fuses my immediate reaction was bad starter so I swapped em out. It was still blowing fuses. After I checked wiring & connections I started thinking I had a bad battery causing my fuse to blow. Low voltage = high amperage. I pulled both batteries & had them load tested & sure enough 1 failed the load test. I replaced both batteries. The new starter also blowing fuses convinced me there was nothing wrong with my original starter so I swapped em back & put my new CME Arma starter back on the shelf & DB electrical starter on the truck. I just new the bad battery was my problem & the truck was fixed. Nope still blowing fuses. Pulled the starter off the truck again & tested both starters w/ jumper cables & without the Power Probe as Squibbly suggested. The CME Arma worked as it should, DB electrical... not so much. Apparently something is shorted inside the starter. I got a nice little light show & burned a chunk outa my screwdriver when I stuck it between the battery & ignition terminals on the solenoid. I've never seen a starter fail like that but there's a 1st time for everything & nothing surprises me w/Chinese junk. Either way w/2 new batteries AND a new CME Arma starter the truck has fired up good several times a day for the last week or so. Thank you to all that offered suggestions & information. I was seriously frustrated w/this one. Yall are awesome.

 

[shepherm]

Well, the more I mess w/this thing the weirder it gets. I just disconnected the negative battery cable & the starter is still hot. How is that even possible?

I didn't see a reply to this, but I made this mistake at least twice... Its the craziest thing, but if you unhook the ground on the first battery, the second battery will the 12 volt wire as the "ground" to complete the circuit. To isolate these you need to unhook the ground and 24v power, or the ground and the 12v wire.

 

[sgms18]

I didn't see a reply to this, but I made this mistake at least twice... Its the craziest thing, but if you unhook the ground on the first battery, the second battery will the 12 volt wire as the "ground" to complete the circuit. To isolate these you need to unhook the ground and 24v power, or the ground and the 12v wire.

Ok. Thanks. I was really wondering what was going on there. I'm still not sure I understand how that works but at least now I know to unhook both sides.

 

[Barrman]

Always unplug all the battery wires if you don’t want some kind of a shock.

 

[royalflush55]

like that but there's a 1st time for everything & nothing surprises me w/Chinese junk.

This is why I like Delco starters and alternators. Reman the originals if at all possible.

 

[sgms18]

This is why I like Delco starters and alternators. Reman the originals if at all possible.

Yep. I knew better but got suckered in by a cheap price. Got what I deserved too. Since you mentioned it do you have a good source for quality rebuild parts for starters/alternators? Or a good rebuilder?

 

[royalflush55]

Yep. I knew better but got suckered in by a cheap price. Got what I deserved too. Since you mentioned it do you have a good source for quality rebuild parts for starters/alternators? Or a good rebuilder?

Look for Wilson 91-01-4376 for the direct drive starter and Wilson 90-01-4277 for the isolated ground alternator. Wilson does high quality remans on Delco cores.

 

[sgms18]

Thank you sir.