theonenandrew

Lately, my '96 F150 4.9L has been having trouble starting cold. It'll crank for a while and eventually start, kicking out a puff of white smoke. Now if I cycle the key (waiting for the fuel pump each time) 4-5 times, it'll start right up. Would I be correct in assuming it's a fuel pump issue as opposed to a fuel pressure regulator issue? Both tanks seem to do pretty much the same thing but I basically already much knew the rear tank fuel pump was going because I've had the truck shut down on the highway running on the rear tank.

Another question I have is how do I check the fuel pressure on this truck? Is there a check valve on the fuel line to hook up a fuel pressure gauge? Or do I need to run it inline?

Things I have replaced already (not specifically for this problem but in general) are the fuel filter, air filter, spark plugs, plug wires, distributor cap, radiator since it blew, and ECT sensor. One last thing to note is that right before I was having the hard cold starting issue, I had hard codes P0117 (Engine Coolant Temperature Sensor 1 Circuit Low) and P1131 (Lack Of HO2S11 Switch - Sens Indicates Lean) as well as pending codes of P0171 (System Too Lean Bank 1) and P0174 (System Too Lean Bank 2). Any help would be greatly appreciated!

justintendo

there is a schraeder valve at the rear of the engine, between the intake and firewall. definitely check the pressure, as this sounds like your issue. check and write down the values for both tanks..will need to see 45 psi key on engine off, up towards 55-60 snapping the throttle. better yet test under load driving to really see what pressure the pump can put out.

Chris_1

iTrader: (1)

96 4.9 runs at lower pressure than the earlier ones - 30 to 45 psi (that changed in 94, previously they ran between 45 to 60).
You will need a minimum of 30 psi for the truck to run; you really want to see 40 to 45 as soon as you turn the key on.