Check valves are in the fuel pump module. Have you noticed fuel going from one tank to the other? That could be a bad check valve.

 

If inertia is good lets run codes. Do you know how? I can send a link

 

No idea on how to run codes .OBD gen 1 on a ford is something I never messed with .

 

You can use a paper clip instead of the jumper.
You should have three digit codes. write them down and post and we will see what you have.

 

Any questions on the OBD 1 test?
OBD-I Diagnostic Trouble Code (DTC) Applications - Ford 3-Digit Codes

 

Will do tomorrow. I'm bout burnt out today. Almost leaning tword restriction in fuel lines somewhere at this point . When I just bled pressure off could only get it to 18 lbs. For awhile. Played with it some , connectors , not really sure what I did got it back to maybe 25 . Spun more connectors the push click type I think it is finally getting about 32 . Maybe it was the constant key off key on. Weird.

 

You can go to an auto parts store and get the code reader most use on this forum. It makes reading codes so easy. Here is what you need. INNOVA 3145 RE: above post 32PSI is not enough.


IF anyone has any ideas that might help Rob that he hasen't done, please chime in.

 

Inertia switch kills power to the pumps when tripped. It is on the passenger side on that truck. Push down to reset. It’s a magnet with a small steel ball that drops when tripped and closes a circuit killing the power. I have heard of them tripping for no reason, but we’re able to reset.

Pressure regulator should be vacuum on yours.

Fuel return check valve (internal) is post regulator, shouldn’t affect manifold pressure. (If it does, I’d like to know how? Honest question)

I would suggest trying your old press regulator along with above suggestions. As well as verify your test gauge if you’re getting erratic readings, they can fail.

On some trucks there are check valves in the pressure fuel lines at the pump fittings, along with the FDM check valves. Mine has them. The FDM check valves are opened by fuel pressure. Pressure line also has pulse dampener, not sure if they can ‘clog up’.

Fuel filter is in the correct orientation? I’ve had leaking fuel bowls/filters clogged filters cause no starts on other types of machines - sucks air / restricts.

Is the same problem on both pumps? We’re both pumps/FDM replaced? Sock filters too? New tanks on both, or old, if old was is cleaned out? Lots of sediment can build up in them.

Hope these help you out.

If you need pages from the Ford service manual let me know.

 

This is just a thought, and I haven't seen anyone else mention it, but are you getting adequate voltage to your fuel pumps? I'm having this issue with a 93 F150 with a 5.0 engine. If the pumps aren't getting adequate voltage they may not produce enough pressure or in some cases may not work at all. My voltage drop happens at the fuel pump relay. I have 12 volts coming into the relay but only 6 volts going out. I have changed the fuel pump relay but it did not change the problem. I'm in the process of running the wiring to see if I have something shorted against the chassis causing the voltage drop.

 

Map sensor. Never thought that would make it not run but I guess seeing as it has no mass airflow makes sense . Runs like new now. Kinda amazed how good.
Thanks for all the replys

 

Did you get a code to tell you about the MAP being a possible culprit.

 

No I didn't . I actually thought it was the fuel line I ran a rubber line from pump to fuel rail to by pass everything still didn't work. So I sat down drank some beer , scratched my watch and wound my *** for awhile. Then I remembered I had a spare map from a 302. Plugged it in for shots and giggles cause it took 20 seconds. Was like yea right this ain't gonna work. And bam prolly turned over half a turn and I was smiling big.

 

Well, I would rather be lucky than good any day. Glad you got it going Rob.

 

I agree. I was changing the fuel system anyway due to both tanks being slap rusted up from the inside they had tons of water and I think Moses was the last one to put fuel in it. It had sat for years and got it cheap. Just wanted to come reply so many threads people don't finish out after others were nice enough to help