I have what I believe is air in the fuel line. If I run my truck for less than 20 minutes and shut it off, it will not restart unless I open the hood, take an ink pen and press the "air valve" looking thing on the fuel rail behind the back of the engine. Fuel will spray all over me and the engine compartment, but as soon as I turn the key, presto it will start every time. It is like I get an air pocket in the fuel line. Where could it be coming from? I think the reason I don't have this problem on long hauls is because the engine builds more heat and burns off the air, but hell,. what do I know.. I am a mechanical FI kinda guy.

Everyone at the office thinks I moonlight at a service station because I smell like 93 Octane .

Justin

 

Do you have 1 tank or 2? If you have 2, does this happen with both? it sounds alot like vapor lock, except that vapor lock is prevalent when hot, not cold, and it's pretty much been eliminated in fuel injected vehicles because the fuel pump pushes the fuel from the back of the vehicle, instead of sucking it from the front of the vehicle. I would check your fuel pressure. Could be a reg. problem too.

Take care,
-Chris

 

It has two, but I only use the rear tank. My mid-ship tank had a pump that does not work. I would have replaced it long ago, but the tank is full of old gas and no place to drain it. Also, the $200.00+ dollar price tag does not help either.

What is the pressure susposed to be? How do I test the reg? Is is similar to a "leak down" test I do on an Injected, Blown Engine?

Justin

 

What engine do you have?

 

Sorry, it would have been helpful...

It is the 4.9L

Justin

 

KOEO: 45-60 psi
KOER: 50-60 psi

Key off: pressure should remain constant for 60 seconds min.

Pressure should reach it's max when the regulator vacuum hose is disconnected and plugged.

Check reg, vac. hose for fuel.

Take care,
-Chris

 

Thanks, I will check tonight and let you know Monday, doubt you will be checking posts this weekend!!!!!!! Have a good one.

Jg

 

It looked good. Now what?

 

If the pressure stats are on the money, I doubt that that's where your problem is. It may just be coincidental. If you left the truck running, would it stall, or just have trouble restarting?

Take care,
-Chris

 

IF I leave truck running, it would run until it ran out of gas. If I shut it off, and I try to restart it, it will attempt to fire once, then just turn over, and over and over, until I press the valve and spray gas everywhere. Then, it will start without any hesitation or stumpling, it just starts and drives normal.

Justin

 

Justin,

Have you changed anything that might allow excess heat to soak into the fuel rail or any of the hoses? Does you engine run at reasonable temps?

I have seen this happen on a vehicle with headers and no wrap. The additional heat rising off the headers vs the stock manifolds allowed the fuel line to get too hot. Similar symptoms.

 

signmaster

No, this is a stock Truck. Replaced a few vacuum hoses, but no mods like headers. The only thing I have done is replace the fuel filter. Thing is I don't recall if this was doing it before I replaced it or after.. This problem is over a year and a half old. Could this be it?


Signed,
Clueless.