no start

[epowers777]

need help 7.3 Lf350 just bought 3 weeks ago wont start. It cranks then sounds like it wants to start but just cranks. I checked all fuses fuel bowl full and pump is working. the waite start light does show and turn off and the check engine light is not on. I do not have a scanner to test codes. Pls help

[epowers777]

wiggled some lines on fuel tank and got the truck started barely made it to the garage no power and missing.Leak in fuel line? they just replaced the sending unit. Can I get codes without a code reader?

[cleatus12r]

No. No codes without a code reader.

The sender was just replaced? Did the supply line get kinked/pinched?
An air leak in the fuel line upstream of the pump (which is under the floorboard) will cause a fuel starvation issue because the pump will suck air instead of fuel out of the tank. Checking fuel pressure isn't really easy on a Super Duty since Ford conveniently failed to put a port on the fuel bowl like on the older trucks. There is no fuel pressure sensor on the engine either, but an indirect way of checking fuel pressure is to monitor the injection control pressure and commanded fuel pulse width. A lot of pressure and a long commanded pulse width are signs that there isn't enough fuel pressure. A pressure gauge can be attached to the fuel bowl drain valve tube at the passenger side front of the engine...just be sure to use clamps on the hose because fuel pressure will be around 60+ PSI if everything's working right. Attach the pressure gauge, open the drain valve, turn on the ignition (can you even hear the pump running with the key on/engine off??), and look at the pressure. The pump should run for 20 seconds.

[epowers777]

Note to self never let truck get below 1/4 tank . It got air in the line. cycle key 5 times then drain valve while cycling don work. To properly bleed fuel system.....

if you have access to an air line tightly wrap a shop rag around a blow tube and stuff it into the fuel filler. Have someone release the bleeder vale on the injector rail while pressurizing the fuel tank. This will force fuel into the line at low pressure [The rag will loose some but not all the pleasure applied] and bleed the air out of the line. When fuel [with no sputtering] is flowing out of the bleeder tighten it down and you should be good to go.

[cleatus12r]

I had that happen one time with a truck I put an engine in. It was warm when it came into the shop (not heated) and when I tried to start it a couple weeks later with ambient temps of about zero.....it wouldn't start.

The pump ran but I had no fuel in the fuel bowl. It turns out that the gas cap wouldn't vent and when the fuel cooled in the tank, it sucked the fuel out of the fuel line, back through the pump, and filled the fuel line with air that the pump wouldn't purge out.
I won't get bit by that again.

[907DAVE]

Wow.....I have heard about gas tanks imploding when that happens.

Good find!

[cleatus12r]

I've seen it a lot, Dave (the gas tanks imploding bit).

We get a lot of fine dust around here and it just so happens that the EVAP canisters get saturated with this dust so they can't breathe. Well, folks around here have just gotten used to the check engine light being on because of the vent system performance (P0446) so when they get plugged up enough, the gas cap vent has failed, and they have steel tanks (the early 90's S-10 Blazers are the worst).......

They get sucked up and usually bend the metal fuel level sender assembly.

[epowers777]

When i was reaching up on the tank I noticed a vent with dirt on it i cleaned it the best i could with my nails. Is that what yo are talking about?

[cleatus12r]

Oh. No, this is regarding gasoline engines. Sorry to confuse you.