Thanks, I'll put the relay back on and check it out. I'm starting to think I've got a short someplace. I just don't know.

Barry

 

Let me give you a little overview of how the fuel solenoid works. Looking at the Larry B pic which was posted, when you turn the key to start battery voltage is sent from the starter relay circuit to pin 85/86 to ground this activates the fuel shutdown relay and pin 30 connects to pin 87.

Now battery voltage flows from the battery thru the fuse link to the relay pin 30/87 to the pull circuit of the fuel solenoid. The fuel solenoid should pull up to the fuel on position. When you release the key from start to on, this circuit should shut down.

Now, with the fuel solenoid in the up position and the key in the on position, battery power from fuse 9 goes to the hold circuit of the fuel shutdown solenoid and it holds the fuel solenoid in the on position.

Disconnect the fuel solenoid plug will give you access to the pins for testing. There are 3 wires black white and red. Black=ground white=pull and red=hold. It is easy to check. Turn the key on you should have voltage at the red pin and no voltage at the white. Now have someone turn the key to start. You should have voltage on the white pin. Let the key go to on and the power to the white pin should stop.

If the fuel shutdown relay is on, it looks like the fuel solenoid would get contant power. Test for voltage with the key off.

 

Thanks Et Ram, I will try this. I don't know if this makes any sense or not, but If I unhook the blue fusible link wire from the battery, it will start and shut down just fine. If I hook the wire back up, the starter sticks and it won't shut off. I have to pull the battery cables off to get it to quit. It has got me really confused. And I still have the other problem with no charging, no tach, and no air conditioning compressor............I have used this truck for eight years with hardly any problems at all, but it has really layed down on me this time, and I'm starting to get really annoyed with it now.............

Barry

 

It sounds like the small brown wire at the starter is shorted to the other small wire at the starter.
Sorry, don't know the color offhand but it's the only other small wire.
Might have to remove the wires from the loom to check it out.
Shouldn't be too hard, if I recall there are are only two or three wires in a small loom until it junctions with the main loom up top.

 

Don't the two small wires hook on the same post? I think I have them both hooked on the small post on the starter...............

Barry

 

This is confusing me too. The blue fuse link powers the fuel solenoid. If you remove that wire from the battery, the engine should crank over but the fuel solenoid will not pull up so the engine should not start. You may need to do a continuity test to make sure this is the right wire. I will see if I still have my notes on checking the wiring at the fuel shutdown relay.

The fuse link wire has no direct connection to the starter. The only connection to the starter is the wire from pin 85 going to the starter relay circuit.

Your truck is the 95 model listed in your signature?

I will look at the start circuit schematic and see if I can find anything.

 

This is how your circuit is arranged. The hold circuit for the fuel solenoid is not shown. Compare to the Larry B picture.

 

Thanks Et Ram for the diagram, I printed it. I am going to take it out to my truck and double check everything. I checked the blue wire off the battery, and I can read continuity from it to the fuel shutdown relay. I agree with you in that it doesn't make sense for the truck to start with it unhooked, but it will. Regarding my starter wires, I have two wires hooked on the small post, and the big cable on the big post. Is this correct? I thought I hooked them back the way they came off, but at this point nothin surprises me. Again, thanks for all the help...............

Barry

 

Here is a drawing of the fuel shutdown relay connector. Remove the relay to do the testing. The pin at the top is the blue fuselink wire. It should have constant battery voltage if the fuselink is good. The power feed when starting on the right is the feed from the engine starter relay. It should have battery voltage only when the key is held to start. The ground pin on the left should have continuity to ground. The solenoid feed on bottom connects to the fuselink feed when the relay is activated. You should have continuity between this pin and the white pin on the solenoid connector.


The only wild guess that I have regarding your problem is that the relay failed internally in such a way that these separate circuits have joined someway. So, when you disconnect the fuselink wire, the circuits are still connected and when you key to start the solenoid does get power to pull on. Once you release the key from start the circuit is dead.

When you connect the fuselink wire, battery voltage is back fed from the fuel relay thru the brown wire to the starter solenoid and the starter stays engaged.

Testing the relay itself would provide an answer.

Any way hope all this helps you find this problem.

 

To be honest I do not recall the wiring at the starter solenoid. I will take a look in a bit and see.

My guess is that one is the feed from the engine starter relay and the other is the feed to the fuel shutdown relay.

 

Ok, I looked at my starter and I have one brown wire going to the solenoid terminal and the red battery cable going to the large starter terminal. According to the schematic the feed to the fuel relay connnects to the starter solenoid brown wire. Not sure why you have two wires unless they made a separate run from the fuel relay.

Do this, get a helper and disconnect both brown wires. Have the helper turn the key to start and check for voltage at each wire. You should probably have voltage at only one. This would be the feed from the engine starter relay.

On the other wire do a continuity test between it and the pin on the fuel relay right side that is marked power feed when starting. If you get continuity then that is the feed to activate the fuel relay. If this is the case I would mark them for future use.

 

Thanks for all the help. I will check this out and see what I can come up with. I looked at the starter wires again, and the two smaller wires have small ends on them, they won't fit on the big post where the cable goes. I don't know why, but it seems like I have an extra wire down there. It sure has me confused.

Barry

 

The large post should only have the red battery cable attached. As for the 2 small brown wires one should be from the engine starter relay. This wire will get powered when you turn the key to start. I guess that the second wire is for the fuel shutdown relay and they just made a separate run to connect with the starter solenoid wire. This is just a guess as my truck only has one wire. They could have made a wiring change. Doing the test I mentioned above should provide an answer.

One more test you can do after you ID the brown wire as the feed to the fuel relay, is test for back feed from the fuselink wire.

Disconnect the fuel solenoid at the 3 pin connector. Separate the 2 small wires at the starter. Put the fuel relay back in the holder. Connect the fuselink wire to the battery. Now test for battery voltage at the brown wire that feeds the fuel relay. You should not have any voltage. If yes you do have voltage, then the relay is bad and somehow back feeding voltage to the starter solenoid. This would be why with the fuselink connected, you starter stays engaged. This is just my guess looking at the wiring schematic.

 

I just wanted to thank everybody for all the help. I solved my starting problem, somebody had run an extra wire down to the starter. I don't know when or why. Anyhow, I got the starting problem solved, but I still don't have a charging system, tach, etc. I have checked the wires going to the engine speed sensor, and it seems that they are putting power to the sensor like they are supposed to. I put a new sensor on, but I still have the same problem. Could anything else cause this?

Barry

 

Also, thanks Et Ram for the diagrams and test procedures. It helped a bunch.

Barry