Ford F550 V10 6.8L does not start

Joined
Oct 16, 2003
Messages
1,015
Location
Northern Virginia
I've had this problem for 2 years and now just finally trying to resolve it.
2012 F550 Super Duty shuttle bus, V10 6.8L gasoline. 53K miles.
It will crank forever and not start. Sometimes it will start after a minute of cranking, if I hit the gas pedal. Once it starts, it seems to run well and drive well. Especially on higher octane.
Once it starts the first time, it will easily start each consecutive time that day. If it seats overnight, back to square one of no-start.


I did some research, read that it's the fuel pump. Got some help replacing the fuel pump with a lot of difficulty, (cracked connectors, spliced hoses).
It's not the fuel pump. New fuel pump does the same thing. Did not make a whit of a difference. No start. I am getting frustrated.
My next idea it's for sure the plugged up fuel filter. Except I can't find it anywhere on the rail on the driver's side. Following the fuel line up and down, no fuel filter. I don't know where it is, maybe the PO deleted it.

I need someone with really strong diagnostic skills. What else could it be? Fuel pressure regulator? If so, *where* is it located, because I cannot find it anywhere on the fuel line and I crawled everywhere under it. This is not some plain-jane F550, this is a long shuttle bus.
Injectors failing? Strange, at only 53K miles.
I think starting fluid makes some difference but it's hard even with the starting fluid.
 
The thing to do is hook up a fuel pressure gauge. Make sure the pressure is in spec while running, and then that the pressure holds after you shut it off. Really, this should've been done before you replaced the pump.
 
A quick google seems that rotted off ground straps are a common cause of your issue.
but that might not pertain to your short bus model.
 
I've had this problem for 2 years and now just finally trying to resolve it.
2012 F550 Super Duty shuttle bus, V10 6.8L gasoline. 53K miles.
It will crank forever and not start. Sometimes it will start after a minute of cranking, if I hit the gas pedal. Once it starts, it seems to run well and drive well. Especially on higher octane.
Once it starts the first time, it will easily start each consecutive time that day. If it seats overnight, back to square one of no-start.


I did some research, read that it's the fuel pump. Got some help replacing the fuel pump with a lot of difficulty, (cracked connectors, spliced hoses).
It's not the fuel pump. New fuel pump does the same thing. Did not make a whit of a difference. No start. I am getting frustrated.
My next idea it's for sure the plugged up fuel filter. Except I can't find it anywhere on the rail on the driver's side. Following the fuel line up and down, no fuel filter. I don't know where it is, maybe the PO deleted it.

I need someone with really strong diagnostic skills. What else could it be? Fuel pressure regulator? If so, *where* is it located, because I cannot find it anywhere on the fuel line and I crawled everywhere under it. This is not some plain-jane F550, this is a long shuttle bus.
Injectors failing? Strange, at only 53K miles.
I think starting fluid makes some difference but it's hard even with the starting fluid.

1 problem here is that someone owned this vehicle before you, did you look on the passenger side of the vehicle for the Fuel Filter, up under the rear right tire? Are your battery connections tight and clean? You need to find the Fuel Pressure Regulator!
 
I've had this problem for 2 years and now just finally trying to resolve it.
2012 F550 Super Duty shuttle bus, V10 6.8L gasoline. 53K miles.
It will crank forever and not start. Sometimes it will start after a minute of cranking, if I hit the gas pedal. Once it starts, it seems to run well and drive well. Especially on higher octane.
Once it starts the first time, it will easily start each consecutive time that day. If it seats overnight, back to square one of no-start.


I did some research, read that it's the fuel pump. Got some help replacing the fuel pump with a lot of difficulty, (cracked connectors, spliced hoses).
It's not the fuel pump. New fuel pump does the same thing. Did not make a whit of a difference. No start. I am getting frustrated.
My next idea it's for sure the plugged up fuel filter. Except I can't find it anywhere on the rail on the driver's side. Following the fuel line up and down, no fuel filter. I don't know where it is, maybe the PO deleted it.

I need someone with really strong diagnostic skills. What else could it be? Fuel pressure regulator? If so, *where* is it located, because I cannot find it anywhere on the fuel line and I crawled everywhere under it. This is not some plain-jane F550, this is a long shuttle bus.
Injectors failing? Strange, at only 53K miles.
I think starting fluid makes some difference but it's hard even with the starting fluid.
Coincidentally, this video came my way just a short while ago. Maybe it can help you.

 
Need to start with seeing if you're getting fuel/spark. Could be something like a crank position sensor or something else electrical. Look under the hood and jiggle electrical connections and relays.
 
If pressing the gas pedal gets it started it sounds like an idle air problem. Might need a new IAC valve or clean it. If it has one.
 
The thing to do is hook up a fuel pressure gauge. Make sure the pressure is in spec while running, and then that the pressure holds after you shut it off. Really, this should've been done before you replaced the pump.
what do you hook up a fuel pressure gauge to? where is the outlet for that?
 
Got some help replacing the fuel pump with a lot of difficulty, (cracked connectors, spliced hoses)

what do you hook up a fuel pressure gauge to? where is the outlet for that?

You put passengers in this shuttle bus? Asking for a friend.
 
what do you hook up a fuel pressure gauge to? where is the outlet for that?
I'm not familiar with your engine, but it's usually on the fuel rail. I would pick up a repair manual for it if I were you. Then you'll have this info along with the pressure spec.
 
I think it's bad gas.
What is a decent and not too expensive electric transfer pump I can use to siphon out all the gas from the 50 gallon tank? It's about half-full.
 
I think it's bad gas.
What is a decent and not too expensive electric transfer pump I can use to siphon out all the gas from the 50 gallon tank? It's about half-full.
Bypass the fuel pump relay, and either disconnect a fuel line at the fuel rail, or better yet, remove the Schrader valve from fuel rail and put a piece of hose over the fitting and into a gas can.

I've done this on several vehicles. Should take about 5 min to fill a 5 gal can.
 
Even by '07 on the F150 Ford had deleted the fuel pressure Schraeder or anything resembling it.

You read fp with a scanner. I hear the collective "OH MY GAW!!!!!" sighs and I can literally hear the eyes rolling.....but be glad Ford even provides a PID. Many don't like Toyota and Nissan -- at least on some models.

Now, maybe the dinosaur 3V V10 has a port, but I doubt it.

Secondly, OP, please stop guessing and throwing parts at it. And gas at it.

You need some data. Why has no one mentioned that OP said it's more likely to start if he screws with the skinny pedal? I'd love to see what the ECM thinks it's seeing for throttle position when the throttle is closed. And if it sweeps predictably as you press the pedal.

Why would "bad gas" cause hard starting but allow it to run fine when it does start?????????

Also I find it unlikely you have a fuel filter. Most likely a "filterless" system relying pretty much on the sock in the tank.
 
Could it be these? Seems like it's not a gas issue at all, but a spark issue. Since it won't start with ether either, sprayed directly into the throttle body.

Camshaft position sensor
Crankshaft position sensor
 
Back
Top