The starter not activating has me stumped. Totally.

The fuel pump could be the inertia switch.

I'm stumped.

Hell put the old ECU/BCU back in at least you had spark.

I'm not saying I'm hard to stump. I'm just saying I'm stumped. Almost as though the ECU/BCU aren't plugged up but that can't be it. He's a mechanic! So it has to be something else... hmmph.

 

With the old ecu/bcu I didn't have spark nor fuel just crank

 

you can't hear your fuel pump kick on?

 

I would try to test the crankshaft position sensor. I've seen where two people mentioned the crankshaft position sensor cuts off the fuel pump but I would be interested in seeing a schematic on that. I haven't seen anywhere in principles of operation where that is the case but you never know they may have designed the system that way.

 

From what I read on rave the pump energizes for 2 sec and then the fpr is deenergized is truck has not started but this is only if truck is cranking. It doesn't just prime like most normal cars. So I will put my old setup back in and put in new cps and see what I have

 

When it comes to electronics I am a DONKEY but maybe someone who knows can comment... isn't there a ground for the computers? And does the bracket that holds the BCU act as a ground? Maybe it is a grounding issue.

 

Maybe a ground to dissipate static, but the wires within the harnesses themselves contain the ground wires for system components. These are more easily identified if you were to look at a schematic.

 

Yeah, this is actually normal when compared to every car I've worked on.

I guess. However still have yet to see in writing or on a schematic that the Crank Sensor actually can provide a signal directly to the fuel pump. Fuel injectors, yes, it does.

 

How did it get to your shop? Was it towed? Maybe the customer had a bad fuel pump and didn't know. HAHAH THAT WOULD BE FUNNY, and easy to fix. I keep coming back to the inertial switch since if the pump is getting power, the CPS is good, and the inertial switch is pushed, you should be getting some action from the fuel pump unless some wire is cut or it isn't grounded somehow.

 

It came on a tow truck. The fuel pump had been replaced already by previous owner already because he had believed that was the issue. The pump only gets power if I use my power probe to give it power. Besides that it gets no power and the grounds are good.