So i finally got around to changing my fuel pump today after the 1st didnt work so i had to ship it back to Ohio. it crunk right up after the first try but ran horribly, which i would come to expect after 3 weeks of sitting up. Now the truck wont crank at all, it will turn over and try to crank but will not crank completly. Pump working good and i get good fuel to the fuel rail, also it is firing, iam lost dont know what, unless the computer is keeping it from cranking. I broke the rollover off so i capped off the line could this be a problem also.

 

Crack the throttle open a bit by stepping on the gas, and see if it will start.

 

tried that already

 

make any difference?

Might just have some air trapped in the rail yet. These are non-return systems......

 

The air in the rails is a non issue. The fuel pump is positive pressure and, all air will be forced out through the injectors completely. You will not find trapped air in this type of system unlike conventional gravity or vacuum based feeds where, they must be bled to ensure proper operation.

The part that confuses me when reading the OPs issue here, is the comment regarding the engine NOT wanting to crank over. If I read that correctly, it means the engine does not want to rotate thus, his term: "will not crank completely". Either the battery is low and doesn't have enough voltage / amperage to crank the engine properly and, IF so, then, that also may be the reason for it not starting due to LOW VOLTAGE SENSE at PCM power INPUT stage thus, the PCM shuts down and, the vehicle will not start.

I recommend checking the battery voltage with a meter first and verify you've got proper voltage of >12.5 VDC at source.

I recommend also verifying at time of KEY <ON>, 2-3 seconds of the FUEL PUMP action. This should prime and bring the line up to full pressure immediately.

<IF> this is not the case, and, NO PRESSURE or LOW pressure is witnessed, there's either a problem with the FUEL PUMP, the FUEL PUMP electrical connector *high resitance, problem / voltage drop across connector at the pump, or, under the driver side door (remove and connect five times) and retest, there's a problem with the FUEL PUMP RELAY, or PCM ground circuit or, we are all the way back to loss of source (B+) at the FUEL PUMP relay due to a failing cell connector or, plain failing of the battery in general.

CM

 

the battery is not a issue, the truck will crank now, for a couple of seconds and then go dead, also if you push the gas pedal it will go dead

 

will not idle

 

So, if I understand this correctly, it doesn't keep cranking over and over but, rather goes for two seconds and then it cuts out. Ok, in this case, there's probably a short and a P0615 error due to a short or fault in the starter motor relay circuit to which, again, after 2-seconds, the PCM will disengage this relay and cut power to the starting system.

So, what needs to be done is to find the reason why the PCM is opening that circuit. The first thing I would do is remove the starter motor and test it across the terminals for a partial short to case ground. Sometimes, the Bendix assembly gets real sloppy and ends up shorting.

Start there first and, I'll see what else is on that circuit. Usually, it's an isolated circuit and, nothing else is sharing that feed or ground that's associated with the starting system due to the excessive current draw it requires but, I'll have to take a look at the schematics and double check.

Ok, here's a quick edit: All the O2 sensors and the AC clutch circuit are all tied together on the same ground bus. I'll go through more in detail when I've got more time to get into the splices and sources for each item. I do recall remembering the O2 sensors and AC Clutch relay taking out a supply but, which one, I can't remember what's tied into what without looking at the schematics and wiring diagrams more closely.

CM