Hi all once again!

Got a new problem for you guys to help me figure out. What would make a FI engine act like its flooding out and dying after a short run on the freeway?

Details:
1994 F-350 351W (just overhauled this winter)
has new TPS, ICM(?).
Dual exhaust dumps right before the tires
new filters in tanks, new fuel filter on frame rail
All fuel lines have been opened and blown out from the tank to the engine compartment fitting near firewall.
Fuel pumps hold good pressure when tested.

symptoms:
smells like its running rich most all the time
after a short hiway run @ 70MPH it will stumble and die when returning to surface streets.
fuel smell near engine sometimes, but no obvious puddles or leaks anywhere.

may be related?:
when on a longer hiway run, I can't use the FWD tank for a long period without the engine stumbling and cutting out or popping at times. But I can swap to the rear tank for a bit then run the FWD tank again for a while. driving up hills it seems to be worse, but I'm in the panhandle of TX right now..good grief!

I am having to drive this truck for work long distances. While I dont expect a vast fuel range, it would be nice if I could go a couple hundred miles on 20 gallons of gas lol. Anyone have an idea on this one?

 

Sounds like you may have two problems:
1. Bad FPR.
2. Bad rear fuel pump (FDM).

 

I am going to replace the FPR as soon as I can, since you are the second one to suggest that as a cause. Thank you.

 

Ok I changed the FPR out...no change...I am at a loss as to whats going on here, anyone have another idea?

 

Excess fuel comes about from;
1. Excess fuel pressure.
2. Faulty fuel regulator, allowing excess pressure or diaphram leaking fuel into the intake.
3. Leaking injectors.
4. Faulty map sensor.
5. Ox sensors not working causing open loop fuel operation.
6. Blocked/restricted return line back to the tank, would raise fuel pressure.
It has to be one or more of these areas.
good luck.

 

Don't forget a bad coolant temp sensor causing the ECU to think the engine is cold causing a "choke" enriched mixture. The best thing to do is pull the codes. Some local parts stores will do it for free.

 

what about a 1988 FI 351W flooding and when u give it fuel to clear it up it looks and acts just like the old carb engines put in new cap rotor plugs and wires, temp sensor andair filter thermostat all help is apreciated from a wounded warrior who it will take me a while to check or get someone to check for me

 

plz help i have a 88 f-150 351W that acts like a carb engine also my gauges on both tanks arent working one shows empty the other over full and i have changed the thermostat, temp sensor temp solenoid plugs wires rotor and cap also air filter i am a wounded warrior so it will take me a while to check the trouble shooting and thx again it floods and clears up when u give it some gas but has gas fumes and rich exhaust

 

Check the vacuum line going to the fuel pressure regulator and make sure it has no fuel in it. If it does, then the diaphragm is bad and the regulator needs replaced.

Also make sure that the vacuum line going to the MAP sensor is connected and not dry rotted.

 

The E in EFI stands for electronic so step 1 when diagnosing a problem is pull the codes.