Hi all,
I know this is an F-150 forum, and I have an F-150, but since there is such a great amount of knowledge here, I wanted to ask a question before I did something stupid or waste a lot of money needlessly.

The fuel pump check valve on my wife's 1995 Dodge Dakota will not allow fuel to stay in the line or fuel rails after shutdown, like a few hours or overnight. So when it comes time to start it, it has to crank a long time before fuel gets to the rails to start the thing up.

I have a stainless steel aircraft fuel line one way check valve that I can splice into the fuel supply line close to the fuel pump to prevent fuel from draining back into the fuel tank. I was considering installing this rather than paying upwards of 400 bucks for a new fuel pump and labor to install it when it's just a .75 cent part that isn't working properly.

My question is, what do you all think?
Will it work?
Is it wise?
And which line do I splice into? There are two lines coming from the pump going towards the front of the vehicle.

Any help or advice will be appreciated.
Thank you

Reloader

 

It probably would work if it would let enough gas pass in the normal direction. Do you feel comfortable in attaching and mounting it? Odd things like vibration could wear a hole in a line.

Normally, if that is the only problem and it rarely is, just turning the key to the run position for a second before turning it to start should correct it. This problem often is accompanied by a plugged filter or poor pump performance. Good luck, even though it is a Dodge.

 

Turning the key to the run position only starts the pump for a second, then it shuts off because the crank isn't turning. I have tried turning the key on, off, on, off, etc, and it helps a bit, but it still cranks a while.

 

That's why I asked. If you turn it on, let it run a second and immediately to start, that 1 second should fully presurize the fuel rail. If the filter is clogged or the pump is weak, it might no be enough. There's also a chance that the starting problem isn't low fuel pressure.

 

If you're comfortable mounting and intsalling it I say go for it. However how much pressure is running through that fuel rail/line? Whatever you splice in has to be able to handle that pressure (yeah I'm Captain Obvious) or you'll end up spraying fuel all over the engine compartment.

 

Two things come to mind. First the reason the fuel pump is shutting off after a second is because it has reached full pressure and the shut off switch is killing the electricity to the pump so it does not continue to run building heat. These are high pressure pumps and capable of building full pressure in just a second or so.
If the engine is not starting then there is probably another problem.
Second if you have a fuel return system and you put a one way valve in, you would/could do much more harm then good. Try to get a fuel pressure gage and see if that is the real reason for the no start.
Good luck.

WLF

 

Hmmm......I was under the impression that the fuel pump shut off because the computer sensed that the enging was not turning as opposed to a sensor sensing full pressure in the line. So, I'm wondering which is correct?
Also, I was thinking of mounting the check valve close to the fuel pump under the bed, nowhere near the engine or the engine compartment.
But the burning question keeps nagging at me.....Is it a stupid idea?

 

Close enough. There's a timer that runs the pump for a second or until it sees CKP pulses, whichever comes first.

I wouldn't. Nothing really wrong with it but even though it looks mundane, there's a lot of engineering into making a system that won't leak hot, cold, vibration, wreck, corrosion, anything. It would be easy to have problems. And then, it's probably not the root cause anyway. On GM vehicles, probably 1/2 pumps over a couple years old won't hold pressure when they're not running. But they don't cause any startup problems. If it weren't such a pain to replace them, tech's would replace them left and right but they wouldn't need it. I expect you've got another problem that could be the pump or filter or not even fuel related that is the cause of your hard start.

 

If the pressure regulator is mounted in the engine compartment pull the vacuum line off of it after shutting the truck off. If the vacuum line is wet with fuel then it needs replacing. The diaphram inside is shot and is letting the fuel pressure bleed back to the tank. I think it was around '97 that Chrysler started putting fuel pressure regulators in the gas tank with the pump but I'm not sure of every engine.

 

Hi guys! Thanks for your replies. It seems like you guys were on the right track because I stumbled across a Dodge Dakota forum and did a search for long cranking times. It appears that quite a few Dakota owners are having the same problem, and it stems from a bleed back check valve that is mounted on the pump which is inside the tank. Apparently, the gasket or seal in that valve fails which allows all the fuel in the line to drain back to the tank which would cause the problem. All that for a $1.00 dollar part that cannot be replaced separately. The entire pump needs to be replaced. Crap! Now....OEM or aftermarket.......hmmmmmm.
I hate the thought of replacing it. Drop the tank or lift the bed............drop the tank or lift the bed.........Damn!
At least I asked the question first in the best place I could think of........HERE!
I used to work on cars all the time when I was younger. But now since I got older.......I don't really like to do it anymore.
I do appreciate the replies, and again....thanks!

Reloader