No fuel pressure at rail [Truck won’t start] 88 F-250 EFI 302 Before I went to FLA for the winter m
 

No fuel pressure at rail [Truck won’t start]

88 F-250 EFI 302 Cab


Before I went to FLA for the winter months, my truck would not start. So I decided to wait until I got back to troubleshoot.

When I got back past Wed after 4 months, I decided to replaced the ignition coil. Why not, I tried everything else. The truck started right up. I was pointing to the front tank. I let it run for 15 minutes, and then switched to the rear tank and the truck stalled and will not start on either of the tanks.

I have NO pressure at the rails with the jumper test. The Vacuum is working fine. I took off the line from the HP fuel pump and it’s priming gas from the front tank KOEO. When I switch to the rear tank, it doesn’t prime gas KOEO. ???

Before installing LP fuel pumps in the new tanks, they tested OK.
I’m thinking that it's the Low pressure fuel pumps are bad.

Before I pull the tanks out, I would appreciate any help!

Thank you,

Runner

New parts I replace last year.

-Injectors cleaned

-Fuel regulator

-Ignition Coil (This year)

-Fuel Filter

- Rebuilt the (Selector valve)

-High pressure Fuel pump

-Front Tank with new sending unit (old Low pressure Fuel pump)

-Rear Tank (with old sending unit (old low pressure fuel pump)

Still no pressure at the rail from the front tank ?

Vinny thanks for taking the time to help!


No pressure at all at the rail with the jumper test. .

Before I left for FLA it would NOT start. When I got back I decided to replace the ignition coil and it fired right. While running,I switched to the back tank and the engine STALLED and at that point the truck will not start at all.


If I turn the kOEO I can hear the HP fuel pump. If I KOEO several times, the HP pump sends enough gas to the engine and it starts for a few seconds,

It seems that the issue is before the HP fuel pump. Maybe it's the Fuel tanks selector valve that I cleaned out.

I'm at a stand still. I'm thinking about looking at the selector valve and make sure all lines are OK, If so, I'll take it out and take another look inside.

thanks for helping!

Runner

I think you will have to follow it up from the tank/s to see where the flow stops. Like you say the selector valve is common to both tanks.

thanks!

I'm going to make sure there are no kinks in the lines at the tanks and look at the Selector valve connections. If all is good, I"ll see if there is flow at the the valve.

Got a gut feeling that's it a bad Selector valve and cleaning it didn't last long. If I have to, I'll take it apart again and see if the valve is not stuck etc.

Runner

Update Fuel Selector valve
 

I had time to troubleshoot why the truck will not start and has no fuel pressure.

I was planning to remove the fuel selector valve and see if it's stuck and try a rebuild.

Previously I put 3 gallons in the front tank and 3 gallons the rear. So I decided to siphon all the gas from both tanks and did the rear tank first and 5 + gallons came out of the rear and there was NO gas in the front tank. When I would turn over the engine, the Valve moved all the gas from the front to the back. The gauges are So inaccurate showing that I had plenty of gas in both tanks.Thats another issue.

It's got to be the valve I would think and will take it apart soon.

If that fails, I'll bypass the valve and run from 1 tank and hopefully that will work.

Any thoughts here?

Thanks

Runner

Were you able to prove that your rear pump is providing fuel to the selector valve or not?

No.

I"m guessing to test if the rear tank pump is to remove the feed line from the valve and see if gas comes out of the line when KOEO.

I didn't take down the valve yet but drained out the gas from both tanks. I could still test this.. How would you go about it?

Again. I was going to see if the valve is stuck. IF all fails I was going to bypass the valve and use 1 tank.

thanks Vinny!

Yeah, you would have to put some fuel back in and remove the line from the valve.

OK I'll give that a try.

I'm assuming if NO gas comes from the rear feed line it's the Low pressure in tank pump. OR if gas comes out of the feed line it's the FSValve. Correct?

I"ll test both Low pressure in tank pumps just to make sure. I can hear the HP fuel pump working when I turn on the KOEO. If the front tank is OK and the back tank is NOT I'll bypass the valve and do direct hookup to the front tank. If that;s the case I'll work once again on the valve but keep an eye out for a good deal for a new one. They currently run for $190.

I did replace it a long long time ago and at that time it was only $60 directly from a ford dealer. Oh well. greed is out there.

I'll keep you posted vinny

Runner

Checking both pumps to the valve is a good plan.
After that you can check the output of each pump thru the valve, to see what you have going on with the valve.

OK .. I'll give that a shot tomorrow.

many thanks for helping

UPDATE:
Just tested.

Both sending gas lines from the front and rear tanks spew gas when I KOEO. That's a good sign that I don't have to pull down the new tanks.

I would think it's a clog valve etc. I'll give that a shot. If that fails, I'll bypass the FSV and go directly to the Front Tank.

I'm going to pull out the FSV and see if the valves are working. Once I do that, I'll put it plug all the lines back in, and test.

Wish me luck.

Runner

worked on truck today




Took out the FSV and tested to see if the valves were working.. It sounded good. However, Still having issues. So I put back the OLd bosch High pressure fuel pump. Vs a new cheap one I put it its place and it fired right up. Apparently the old pump is giving more fuel pressure. However, it's still taking all the gas from the front tank and puts it in the rear tank and I starting having the same issue.

FSV is not good.

Tomorrow I'm going to completely bypass FSV and just run from the front tank. I hope. Then I'll pull the FSV again and check out the rings etc.

I'll keep you posted.
Runner

Before you pull the valve out, disconnect the line going to the HP-Pump and see what comes out for each tank selection.