Replaced fuel pump 11 months ago. Car died again while driving. Found that the engine was not getting fuel. No voltage at the pump. Checked the inertia fuel shut off switch - no voltage. Checked the fuse and fuel pump relay - both good. Found the relay not closing. Checked the coil voltage - had 11.87 volts. Is this enough to energize the relay? Bypassed the relay and had voltage to and thru the inertia fuel shut off switch and car still will not start. Any other ideas?
Yes we have spark. If I give it a shot of starting fluid it will fire right up.
July, 6, 2011 AT 9:25 PM
Dandy. 11 volts is plenty to energize the relay, but the problem is the Engine Computer isn't turning it on, and that is because it's not getting a signal from a sensor telling it to do so. That missing signal, I suspect, also fires the injectors, so even though the pump is running with the relay bypassed, the engine still isn't getting fuel.
Now I have to admit I'm not familiar enough with your vehicle. Ford started running their fuel pump the same way Chrysler did it for many years, but even Chrysler has changed their system now so the engine can still run when one sensor fails. Typically one sensor determines when to fire a coil and the other one synchronizes the injector timing. On the Chrysler engines, the injectors are fired according to the camshaft position sensor signal. Both your crankshaft position sensor and camshaft position sensor look suspiciously similar to what's was used in the Jeep vehicles but of course that doesn't mean the computer works the same way. Even though the camshaft position sensor is a bolt-in item, rather than throwing parts at it, see if you can borrow a fault code reader from an auto parts store that rents or borrows tools. If there's a fault code stored in the Engine Computer, that will direct you to the circuit with the problem.