He has replaced computer and tested everything we can think of. What would make a engine run when he pours in gas to the throttle body but not otherwise.

 

Lack of fuel injector operation.

The injectors are bank-fired directly by the PCM.

Have the KOEO and KOER codes been pulled yet? Always the first step...

Steve

 

In less technical terms no gas. Now that that's narrowed down you should check the fuel pump and fuel filter. As noted above injectors not working as well .

 

Hes done that Replaced filters checked pressure,checked for leak down,replaced sensors, took computar out of running truck and still no dice. Checked both tanks and pumps and relays diverter valve,inertia switch ok. Im telling you we talked on the phone there is somthing we are missing.

 

I agree with projectSHO89, check for codes. Have you checked for voltage signal at all the injectors with a noid light?

 

Yes he did check for voltage but I don't remember how. I agree he should check for codes at this point and told him so. The more I think about it I believe its a electrical component possible cam shaft pos. sensor.

 

Just a thought...

The Fuel pump may still be bad even if the leakdown test holds true.
I have witnessed this first hand. You may have also checked the fp relay with a volt meter or listened to hear it spin on when you turn the truck to battery position, but I will mention it anyway. Here is another one, what about checking the inside tank condition? I have seen a tank removed from a car and the lines inside were clogged shut with crap from the tank.

Just a few to think about.

Hope you get him straight.

 

Umm what about the fuel cutoff relay switch? As its name implies, I assume it cuts the fuel somewhere between the pump and the injectors....worth a look, but yes, checking the codes is paramount.

Did testing the fuelpump/flow system entail actually watching fuel pump out? (I assume you can just disconnect the fuel line and direct it into a jar)

If so, then if all else fails, you have to check each and every component downstream from there.

Is there an anti-dieseling solenoid, and, if so, has its operation been checked?

 

He has checked the inertia switch and disconnected fuel lines and watched it pump out and even tried to stop the fuel with his thumb and could barely hold off the pressure. Its down to the codes again. Thanks for all the posts I am sure Fireman 54 appreciates it And I do too. Its great to have a place to hash it out.

 

Maybe I missed it, but I didn't see any mention of checking the schrader valve....If he's getting fuel there then something is not right with the injectors/rails.....

 

The injectors are not letting fuel into the engine.
Battery is supplied to all the injectors at the same time.
The computer supplies a ground to operate the injectors in groups of three.
You have proven the engine will run by introducing gas into the throttle body ruling out ignition and the use of a trial computer.
When testing the injector signals, you must see the pulsing take place or the injectors will not flow any fuel during cranking.
AT crank time the dist pick-up turns the fuel pump on by triggering the computer to put a ground out to the fuel pump relay, operate the injectors as well as the correct ignition firing order.
With the system having the computer replaced and other work done I doubt there will be any meaningful codes set because the motor has not run to log the fault in a normal way.
With fuel pressure present, the injectors are ready to admitt fuel if they are operated.
I would be looking at the harness from the computer to the injectors for an open.

 

Good suggestions. I agree bluegrass after much thought and disscussion I do believe it has to do with the injectors being fired.

 

Agreed. I would use a noid light to check and see if the injectors are receiving the proper signal, and go from there.

 

I am getting the pulse at the injectors.
when ever you crank over the engine it tries to start at first then just cranks.
When fuel pump runs and I put vacuum to fuel regulator I can hear fuel return.
I have 60 psi from rear tank and 45 from the front.
I have tied three different computers and all do same thing.
No codes.
Removed fuel rail and cleaned rail and injectors.
When I get home tommorrow I amgoing to remove the plenom and remove the injectors to see if the are allowing fuel through is my next step.

 

Try to start it a few times, turning the key off in between, and then pull a plug and see if it's wet.