My van is having problems with fuel delivery. Basically the problem seems to be that the pump cannot deliver enough output to keep the fuel in the lines properly cooled. When the van gets hot, I loose a lot of power, and if I shut it down and let the heat soak into the fuel lines, it will stumble at restart until I get the vehicle moving again. The engine is not overheating, in fact the coolant temp is normal. But the underhood temperatures can still get pretty high. When the underhood temps get high, the fuel pump starts screaming. The pump was replaced last summer, and is doing better than the original, but my question is that if I replace the pump again will installing one made for say a Mustang or other Ford model fit correctly, and would it really be of any benefit, or are all the pumps going to be about the same. I'm just trying to get a system that can keep up. When the ambient air is cooler, everything works better, even if the engine is warmed up. Its when the temperatures get around 90 or above that this problem exposes itself.

 

That sounds like the pump is getting weak. There may be an obstruction in your fuel line before the regulator, putting extra load on the pump. Do you have another pump to try?

Since you've replaced the pump before, you can take to old one to one of the Mustang houses to see if the size and shape are compatible. My feeling is yes, but I've never took measurements of either to know for sure.

 

what's the fuel pressure at the rail with engine running?

was there any debris/crud in the fuel tank or the pump filter sock on the last change of pump?

is the modified exhaust system dumping more heat into the fuel tank or fuel line system? common problem on rock/hill climber rigs or hwy tow rigs.

how old/many miles on the FPR? can be failing and dumping extra fuel under heat soak.

any major modifications blocking engine compartment air flow?

any restrictions in fuel return line?

any fuel line/filter restrictions? extra inline filter?
did Ford every get this one wrong in their Aero service manual
quote
NOTE:
The in-line fuel filter should last the life of the vehicle under normal driving conditions.
--------NOT

last resort
http://www.heatshieldproducts.com/p_...uel_sleeve.php

when i used to tow heavy with the Aero in the mountains and w. deserts, the under hood components would get so hot that i would have to let it set an hour with the hood open before checking anything. the dipstick handle would leave burn blisters.
but the rig ran like a champ, never overheated or boiled over the coolant nor any signs of fuel boil.

 

When the vehicle is acting normal, the fuel pressure is between 35-45 psi, depending on throttle.

There was no crud or debris in the tank that I recall. Everything look pretty clean.

My modified exhaust does dump a lot of heat, but it dumps it at the tailpipe. The muffler i have no runs cooler than my last one. I have wrapped my crossover pipe to stop heat from getting into the trans pan. Wrapping had no effect on the heat soak into the rail. As best i can tell, the fuel tank itself isn't overheating.

The FPR is the original, I suppose I can pursue testing/replacing it. How involved is that on a 4.0L. I have done that on the 3.0L and it was a pain (I did it without removing the rail).

Airflow has been opened up in the engine compartment. I also have electric pusher fans that keep airflow going when the AC is running or if the coolant reaches a certain temperature.

Since the fuel pressure tests come back as normal, I don't suspect a restricted return line.

The fuel filter has been replaced twice. Doesn't help. Best I can tell the filters are not plugged.

I will consider additional heat shields or sleeves. The heat wrap I used helped a little, but it was more to protect the transmission than the fuel system.

 

The FPR is located on the front passenger side of the fuel rail, and is pretty easy to remove. Just 1 or 2 bolts, and it pulls off. It might be stuck on its O-ring, so just pull firmly. The harder part is to pull the fuel line off of it.

 

Ok, I changed out the FPR, and can feel the van is a little more peppy and has better response. Not hot enough to see if it still acts weird in the heat, but so far seems like the FPR was the ticket. I also changed out the t-stat with an OE one, and replaced the temp switch (gauge indicator).

 

disconnect the + batt. lead for 5 minutes to reset the PCM KAM memory. fuel mapping probably off from defective FPR, will correct sooner if KAM cleared.