I have read through many forums here and am wondering if anybody would be able to help. My truck stopped working a couple days ago, i had it towed home and it fired up a couple hours later. I drove to my mothers and it hasn't started since. Engine cranks just fine. I have 12 volts going to the coils, the coils, and and spark plug wires are within specs when i test the resistance. All fuses in the engine compartment fuse box are good, not positive on all relays though. As for the fuel side with KOEO i here the pump kick on for a few seconds then turn off-every time. I get a faint smell of fuel at the air intake but it might be residual-definately not alot of fuel if any is being injected. I attached a GM node to the injector to test it as the node marked for Ford did not fit-i'm resonably sure they work the same. Anyway the node did absolutly nothing when i cranked the vehicle. I also checked the inertia switch and it was not tripped either.

I could really use some ideas here if anybody could offer imput it would help. Answers the these questions may also help. 1) Would a bad PCM prevent the plugs from sparking and the injectors from pulsing/injecting fuel? 2) Would any of the relays be responsible for these symptoms/how would i test the relays? 3) I have read of a sensor located on the bottom of the engine by one of the pully's, it said the sensor sends a signal to the PCM-would this sensor cause the same symptoms and if so how would i know if its the sensor or the PCM? 4) I have cranked the vehicle at night and noticed no free sparks from grounds but i read that a bad ground could cause the symptoms. I have ensured the grounds are clean and secure on the firewall, if their are any others i should check where could i find them?

FYI:No anti theft, fuel pressure at rail is ~40PSI gauge reads 38, vehicle just had oil changed, and I replaced fuel filter, fuel pressure regulator, and air filter hoping for an easy fix.

 

1) Yes
2) Probably not if the fuel pump priming cycle is present.
3) Crankshaft sensor is as important to engine operation as is your heart to your body. Can't run without one.
4) If there's no crank signal, there will be no sparks.

Have you checked to see if there are any stored fault codes?

 

check the simple things check for spark having 12 volt at the coils dont mean nothing.

a bad cam pos. or crank sensor will hold you up.

other than that im not sure.

 

In the other thread you said that you have NO SPARK - which is pointing to the crank sensor.

 

Thankyou for the responses,
Guess i forgot to mention in the original post: I have no spark at the plugs, and no stored codes show up on my OBDII scanner.

Got a new Crank Sensor from Autozone today-will install later.

Would a Cam Sensor cause no pulse at the injectors? I could not find anything that said it would when researching.

 

No. If the cam sensor signal only is missing, the PCM will make a one out of three guess for the injector timing.

 

These trucks will run with out the cam position sensor being hooked up.

The crank sensor is my bet and it is located behind the a/c compressor.

A quick test you can do before you unbolt the a/c compressor is to unplug the sensor and test the resistance in that one as opposed to your new one.