Hello I have a 1993 Ford F-250 with a 7.3 nonturbo. When I am on my back fuel tank and the truck sits for a while it takes a little bit to start. I checked for fuel leaks and couldn't find any. So I decided to get a fuel check valve. Where should I install the fuel check valve? Will this check valve work http://www.siliconeintakes.com/index.php?products_id=9581 thanks

 

This may temporarily relieve your problem, but somewhere between the fuel selector valve and the fuel in the rear tank it is leaking.

My first vote would be the rear sending unit has a pinhole in it, second I would say the selector valve..

Put it as close to the fuel as possible. This will require cutting and splicing your fuel line which is iffy to say the least when it comes to nylon.

 

Where can I buy these parts can't seem to find them anywhere? Also where is the fuel selector valve?

 

Could it be a leak under the truck? All I checked were injectors, fuel filter, and pump.

 

When I say take a little bit to start I am talking 3-4 seconds 5 seconds top

 

Well it seems to be doing it on both tanks. I switched tanks to see if it did it on the front tank and it's doing the same thing. I have an inline fuel filter don't know if that could do it. Also I see some dirt on the the steel line where it connects to the fuel pump. Which means it's leaking a little and dirt is getting stuck to it. What would you use to seal up the line fittings teflon tape? Should I get rid of the fuel filter and put a check valve there? Where is a picture

 

It sounds like an air leak somewhere. 3-5 seconds is nothing to really be worried about though. Little long for hot but it could be your injection main rotor in the pump starting to show its age.

I prefer to double clamp any rubber lines where they go to a hose barb/filter and I've never had the need to use teflon on one of those fuel pumps. It doesn't seal on the threads like a water pipe, it has a flare type connector inside of it. Try loosening and tightening the fitting a few times to help reseat it.

Get the truck up to operating temperature, shut it off and see how long it takes to crank, if it fires right up your pump is fine, if it mainly happens after sitting 20min to a couple hours it's air related/fuel drainback. If it only happens when cold your start times are perfectly normal.

 

If I installed a check valve where the inline fuel filter is and sealed the threads on the fittings do you think it could fix it. Considering it does the same thing on both tanks? I put a new fuel pump on it about 4 months ago. After it warms up and I turn it off and go to restart right after I turn it off it it fires right up.

 

does it only do it when the engine is still warm, after having sat for at least 10 minutes or so?

 

It takes the longest to start in the morning. It will start right up 20, 30 minutes after it sits. Anything after 40 minutes it starts to take a little bit to start. Going to try to seal up the threads on the metal fuel line and install a fuel check valve where the inline fuel filter is. Do you think that will help? I also have 8 new motorcraft glow plugs to install.

 

Does it smoke white while cranking, or no smoke?

If smoke, your problem is glow plugs. If no smoke, you might be right with a check valve.

Also, if the check valve fixes it, you might want to try pulling the bed(not that hard, actually) and go through both tanks, replacing the (probably shot) fuel pickups and checking the O-rings on the lines that connect.

 

What color smoke while cranking? Will the color be different if the engine has a lot of blow by.

 

I know there is a lot of dirt down at the steel fuel line where it hooks up to the fuel pump. So maybe the line is slowly draing while it sits for a while.

 

White generally. (totally unburned fuel)
You'll see some gray/black when it is actually starting, which is normal. If it's more than just a puff, though, and keeps smoking when it's running, that's another problem(usually retarded timing or injector issues).
No, because the oil won't be hot enough to actually vaporize at cold start.

Aand all IDIs have massive blow by. It's just the way things are; the engine was pretty much designed around it, what with the very large ring gaps and all..

 

Ok thanks will be checking that. I know there is a lot of dirt down at the steel fuel line where it hooks up to the fuel pump. So maybe the line is slowly draining while it sits for a while. Do you think that could cause it? Also putting the check valve where the inline fuel filter is might also help. What do you think? It just started doing this starting problem the beginning of the week. Just went out to start it but from what I can tell it didn't smoke while cranking but as soon as it started there was white smoke and then turned to black. Was hard to tell while cranking because of pouring down rain. Do you think this check valve is big enough http://www.siliconeintakes.com/liquid-air-adapter/aluminum-one-way-check-valve-8mm-barbed--p-9581.html and would it be ok to put it where my inline fuel filter is now? Here is a picture of where my inline fuel filter is you can see the fuel pump on the right.