Newbie here. My 1990 Dakota with the 3.9 engine recently won't start. Thinking it was the fuel pump I get under the truck and have a friend turn the key. I hear the fuel pump so then I disconnect the fuel filter on the frame rail and have the key turn on and fuel pumps out strong. I connect the fuel filter and then disconnect the fuel line that goes into the throttle body. Crank the engine and fuel is pumping strong out the fuel line. So somehow the throttle body isn't getting fuel. What gives???......Is it a fuel pump relay? What could it be? Appreciate all any any information

 

Is this motor one with the throttle body injection unit, or is it an injector per cylinder?

If the former (or the latter for that matter!), I'd get a set of NOID lights and see if you're getting the pulses.

If you're not, it's time to back track the wiring to the ECU and make sure no plugs are loose.

(On my 1988 truck, the ECU just flat quit on one injector ... but overall, I understand that's a rare thing.)

RwP

 

I have the one with the throttle body injection unit.....Hmmmm... I guess I'll have to pick up a NOID setup......If I'm getting pulses what could it be????