Won't start, Fuel Shut off Solenoid?

[Blacksdieselhp]

Hi, I have never done anything to a 1st gen truck, but my friend has one and it won't crank. I checked for fuel at the filter and at the injectors. Its getting plenty. So what could it be? I'm sure these trucks have a fuel shutoff solenoid, correct? I'm thinking thats what it is. Is there a way to bypass it like on the 2nd gens to see if thats what it is? Where is it located?

 

[Doughboy21kd]

I know on the 8. 3L cummins you can use wire ties and tie it open, but then you cant shut the truck off..... I dont If the 5. 9 has one or where its located... Sorry... someone will chime in i'm sure

 

[R C Cola]

Fuel Shut-Off ?

If you have plenty of fuel at fuel filter and the injectors. On my truck the shut-off solenoid comes before the Injection pump ( located at the rear of the injectiion pump) with a couple of wires that connect with push on spade terminals. When I have no fuel to the injectors it is because the 12v supply wire to the solenoid has vibrated off or broken into close to the solenoid. Test llite and check for 12v at the terminal. Did you loosen the nut at an injector and get a spray under pressure (not just a dribble) ? R C

 

[Blacksdieselhp]

Yea, I got spray at the injector. And I also took the screw at the fuel pressure port out and got a thick stream of fuel. I'll replace the FSS and try that. Thanks guys.

 

[R C Cola]

Fuel ?

Spray of fuel at the injector indicates the solenoid is open and the injector pump is working. When I ran out of fuel I had to crack 3 injectors to bleed out the air and then tighten and she would start just fine. R C

 

[Blacksdieselhp]

What else would cause it not to crank? It has 12v on the FSS wire, it has fuel to the injector pump and to the injectors. it hasn't been ran out of fuel. He said he just came out and tried to crank it and it wouldn't.

 

[DonTX]

I don't know what it is, but apparently it is contagious and got infected from mine. Sounds just like mine, I am ready to pull the IP and get a rebuild. .

 

[jimnance]

If you are getting fuel to the engine that seems to leave air, and timing. Assuming you don't have some sort of blockage in the intake system I'm thinking that somehow your fuel pump is so far out of timing that it won't start.

 

[R C Cola]

Won't Start

Good point. When everything else is normal with these engines and you are sure that you have fuel and you are sure of air flow, THEY WILL FIRE ! I have on occasion had to bleed the air out of injector lines more than once because I did not do a good job the first time. Right about now a shop would put a fuel gauge after the lift pump and before the injection pump just to be sure of sufficient pressure of supply. Are we sure no repairs or modifications were made recently that might cause a problem ? R C

 

[DonTX]

AND don't forget: Getting fuel thru the loosened injector nut UNDER NO PRESSURE is not the same as knowing it is popping the injector in the cylinder.

 

[dpuckett]

Good point Don/TX. When you crack the injector line, does the fuel leak out, or does it spray up to the underside of the hood? If it is the former, you arent getting enough pressure to pop the injectors. If the latter, you have adequate fuel and need to check other options. You can pull the AFC cover and check in the "well" to see if the guide pin comes back when you cycle the throttle shaft on the pump. If it is stuck, it can cause enough fuel blockage to not pop the injectors open.



Daniel

 

[Blacksdieselhp]

Well, I replaced the Fuel shutoff solenoid. It cranked right up and ran perfect. I drove down the road and back. All was good. The owner came to pick it up about 5 hours later and it wouldn't crank again. So what now? Injector pump? Could the new FSS have gone bad that fast?

 

[Sri Ram]

Let's get this straight, is the engine turning over but not starting? Or, is it not turning over?

 

[1stgen4evr]

"and it wouldn't crank again. "



"Let's get this straight, is the engine turning over but not starting?"



It is a southern thing. "It won't crank means anything from: it won't turn over to I killed the pair of battries (which can be one or more batterys) and burned up the starter and it still wouldn't (fire up).



And I am southern by the way so I know the language. We also have cadilac converts and university joints on some vehicles. Ratiators are the heat disapation devices on some. Some drivers have had the misfortune to strike a telegram pole, quite strange considering that the wires atop the poles have upwards of 100k volts flowing through them. But I digress.



The only way to know if the problem is with the solonoid is to take the plunger out of the solonoid and repeat the cranking process along with the bleeding and so forth. Use the manual shut off if it does run and then find out what is wrong with the solonoid or current flow to it.



The fact that it did run for at least once is a pretty good indication that the pump itself is working. In my experience, the wire to the solonoid is the culprit. The spade connector will/can be attached and still not flow current to the solonoid. Be certain that the spade slides on TIGHT. I have also seen intermitent flow of current to the solonoid which turned out to be a bad key switch.



Good luck.



James

 

[R C Cola]

Won't run?

Some good points here so far. You can temporarily run a hot wire from the battery directly to solenoid, make sure the connector slides on good and tight.

(you will have bypassed everthing with this wire) I have had a wire that looked good and the terminal was tight (from vibration) break the individual strands inside the connector. When I removed the terminal from the solenoid the crimpon terminal came off in my hand. If the jumper fixes the problem you will still need to find exactly where between the battery and the solenoid

you are losing power.

 

[Blacksdieselhp]

Sorry, the truck will turn over but will not start. When I replaced the solenoid, it started right up. Them a few hours later, the owner came to get it and it wouldn't start again. It has power to the spade. I checked it with a test light and checked it on the threaded stud that the spade goes on. I did use the old spring. The new one didn't have a spring. I thought that was odd.

 

[DonTX]

You might put a voltmeter on the spade of the solenoid. I did, and when cranking the voltage to the FSS was down around 3-4 volts, not enough to open it according to the book. (I then put a set of jumper cables from another vehicle to the solenoid, in my case, it still would not start though).