Hello,
I have a 89 f150 4x4 5.8l v8.
The truck was a freebee, previosly had Propane conversion.
I recieved the truck with no fuel tanks or pump, I installed a tank w/working pump, and a front pump,replaced EEC relay (had been cut away),

Now the engine turnes over,
I have spark at the plugs,
Fuel to the fuel rail,
But no fuel in the cylinders so it won't fire. (Spark plugs are dry)
Check engine light is on.
Fuel pumps stop pumping after a couple of seconds unless cranking engine.
Fuel is not returning to tank (leaking at conections)...Blocked @ Fuel crossover?

Q. How do you measure fuel presure? A tire @ fuel rail?
Q. Is there a way to test injectors?

I'm sure theres more that I missed ,any help would be appreciated.
THX

 

Well I hope I didn't break any forum etiquett, if so I apoligize.
Any way just thought I would add that while I was checking things under the hood I stuffed a test probe in the wires that go to an injector and there is a wire with power.
Q. Should this have constant power or should it pulse?

Again any help would be greatly appreciated

 

The EEC system is a "ground side switched" system meaning the sensors all have a 12 volt supply, and the processor supplies ground. You can use a 194 peanut bulb like in the instrument cluster, or on the tag lights. Spread the metal leads out where they point down and unplug one of the injectors, and put the metal leads of the bulb into both of the metal connectors of the fuel injector plug. Crank the engine. If the bulb flashes, that means that the processor is sending the ground signal to the injectors. If it doesn't flash, there are several possibilities. Good luck.

Robbie

 

On a LPG system the wire feeding power to the injectors is cut and if it is a duel fuel system they put a relay contact there. I would think that there would no power at all at the injectors. From the cut there should be a jumper going to the IAC valve to supply it with power.
The HEGO sensor wire will also be cut and it should have a HEGO simulator hooked to these wires.
The ECT sensor wire should also be cut an a 20K Ohm resistor put in series there.
An LPG system most of the time will not use injectors unless it is a duel fuel system in a cold area then it is warmed up on gas and then switched to the cheaper LPG to run on.