jumbofisher

2010 4.6L 4x4 will only fire but not stay running when attempt to start while engine is still warm is made. Sometimes. Everything runs great when it does get started and runs for as long as you want. All normal operating temps/pressures/voltages/etc. What is causing this aggravating problem? Been happening for a while now.

Mark_

Interesting problem. Start by checking if you have a flood condition on restart. Maybe you have an injector that leaks after being shut off. You can check this with a fuel pressure gauge connected at the rail to see if the rail holds pressure once the pump is turned on Key on, engine off test. The pump should run for a second and then shut off, this pressurizes the rail. Check to see that the rail pressure holds.

If you have a scan tool with PID capability you could look at the O2 readings and the fuel trims to get some clues as to what is going on.

Mark_

I should add it could also be a fuel starvation issue. Again, you need to test with the fuel pressure gauge hooked up to see what is happening on restart when it won't run. You could also have a bad fuel pump relay that will not close the circuit when it gets hot. This is a common problem with pump relays.

Other than a bad relay, there are quite a few things that could cause the computer to shut off the injectors like loss of cam or crank position sensor signals. But first step is to see if the pump is charging the rail and if the injectors are being pulsed by the computer.

jumbofisher

Tried a few things. Took it to a mech I trust he hooked up his analyzer and couldn't get a readout. Took it to Ford dealer here they could analyze it but there were too many codes and the first try was the evap canister purge valve making too much of the wrong noise. Replacing didn't help and couldn't afford more tries.

Initial scan produced P025A,P025B in history also found P2006,P2007 in KOEO.
After an hour of running with new purge valve the truck stalled.
Second scan produced P025A,P2006,P2004.
Next recommendation is a new PCM but a previous dealer tried a different PCM with no change @ 49083 KMs. There is 143583 KMs on the truck now and the problem seems to occur when the gas tank is below 1/2 full. This is the fatherinlaw's truck and I've been driving it a week on a full tank with no trouble.
Ford dealer found a weak battery and I changed that myself at home. Didn't get a direct answer to the fuel injector manifold pressure question and not sure where to do it myself

ji603

Previous posts on here for same problem. Search for fuel sender, collapsing fuel tank, purge valve.... I'm sure you'll find it.

ETA. Found one for you

https://www.f150forum.com/f38/new-gu...ations-107053/

jumbofisher

I got the truck back from the dealer before PCM replacement was made. Filled it up with gas and changed up to a bigger battery. Ran it through the first tank and 1/2 way through the second with no more problems. Old battery was weak. Rated at 650 cc amps and load tested at 550. Pretty sure the new battery fixed things.
Thanks for all the info.