Have a 1987 Ford F150 4x4 inline 6 (4.9l) 4 speed. Bought this truck and it had been sitting for 5 years. Put new gas tank, fuel pump in gas tank, fuel filter, fuel pump on rail, pulled all injectors and cleaned them, brand new computer. Truck will run if you spray gas in throttle body. I have 50 lbs. fuel pressure. Don't know what else to do. All parts put on are brand new. Please help

 

I'll give you the same advice I gave you in your last thread....


Confirm that the injectors are getting juice while cranking.

 

Yes put a rented NOID light on it and see if it flashes while cranking.

 

I have a pulse on the injectors. Used NOID light. Don't know what else to try.

 

Have you checked the compression? Could be the cylinders are washed down with gas. If so, put some oil in the spark plug holes after cranking over the engine with the plugs out to clean all old gas out of the cylinders. Bought a car cheap because of that very problem once.

Also, it's possible the timing gear is bad and thrown the cam timing out, or just stripped all together. Compression test will point to that too. Make sure rotor is turning when cranking over.

 

OK, so it runs when you squirt fuel into the throttle body. You have fuel pressure at the rail and you have injector pulses. Have you inspected your injectors? I do see you have cleaned them, but do they work? Best test would be a spray pattern test.

 

Thanks for the replies. Took all injectors out cleaned them and checked that they were spraying. Have 50 lbs. of fuel pressure. I didn't pull spark plugs to see if they were washed out with old fuel. Will try that. thanks

 

I missed the part about running when fuel is sprayed in. For some reason the injectors are not putting fuel into the cylinders.

 

Engines need fuel, compression and ignition to run.<br /><br />For the purpose of hearing the engine fire up, it will make no difference if the fuel is sprayed from the injectors or sprayed into the throttle body. The fact it does fire when fuel is sprayed into the throttle body tells me you have ignition and compression.<br /><br />If all conditions are as you state, there will be fuel delivered from the injectors. So why doesn't it run? Obviously because you do not have fuel delivered from the injectors. This can only be explained as an error in measurements.<br /><br />Go back and check your fuel rail pressure with another known good pressure tester. Check your injector firing. NOID lights are great, but make sure you are not losing electrical power under the load of actually connecting the injector. One way to infer this would be with an automotive stethoscope. Listen to each injector for that distinctive tick.<br /><br />Your 50 lb of fuel pressure makes me question your measurement. 4.9 six does run higher pressures than the V8's, but that is too high. How are you measuring this?. The proper method would be with a gauge attached to the Schrader valve test port on the fuel rail. The engine does not have to be running for this test and the bypass type fuel pressure regulator will keep the pressure around normal running pressure which would be in the mid 30's range. You are not just dead heading the pump, are you? The pump should be running continuously which can be accomplished with the engine on and the fuel pump test pin grounded on the EEC test connector.

 

Deleted as just saw the year with the lower fuel pressure.