Hello friends, my D1 with 113k stalled out while driving one cold night and would not restart ie crank just fine but would not 'catch' so I pushed it into a parking lot as a cliff was nowhere to be found. When I listened for the fuel pump it was very quiet,unlike what it used to sound like. I replaced just the pump with the airtex pump from auto zone( I forget the part#) I primed the system with the key and after a couple of cranks off I went.
Well over the past 3 weeks it has become increasingly harder to start. I'd say about 4 long attempts before it finally sputters to a start, the engine spins strong. New fuel filter last year,new plugs,plug wires in the mail,newer battery and alternator.
Today I picked up a fuel pressure gauge and hooked it up. Key completely off I get 8psi, engine running 28 psi.
I figured I'd double check my earlier work. I removed my fuel pump assembly and tightened down the hose clamps that secure the two vertical hoses attached in the pump and then reinserted the fuel pump in tank.
-With key in pos 2 the pump now sounds very strong and fuel pressure rises around 38- 40psi.
-With the engine running around 34-38psi.
-As soon as I turn the key completely off or while in pos2 and the pump times out, right back to 10 then to 8 psi again, immediately.

It will now start right up if I let the system prime for a few seconds, or 2 quick starting attempts. Should I be holding fuel pressure longer with the vehicle off? Or does this sound normal? Keep in mind my plug wires are in bad shape.
-Thank you

 

try pinching off the vac line to the fuel pressure regulator to see if the regulator is functional.....other possibilities....you may have a leaking(dirty) injector or two, bleeding off the pressure, and partially flooding the engine when not running, keep us posted

 

Thank you, I'll try pinching the vac line, what should I be looking for? My fear is a leaky injector, I have no idea on how to, or cost of repair.

 

Ok I removed one side of the vac line and there is a lot of suction. After blocking off the suction with my finger and waiting 5 minutes, no fuel leaked from the regulator and my psi gauge read 48psi. I reeved the engine and it held 48psi. I reconnected the line and the gauge crept to 38psi. When I reeved the engine the psi would rise then drop to 38. When I pinched the vac line there was no change in psi,but I could hear the engine dip slightly.
I'm not sure if my check was the correct method. Any insight would be appreciated. Interesting though,today when I initially plugged in the gauge it again read 8psi. Then fuel pump only, it read very high 48psi. With engine running it stayed at 48psi for a few minutes. This was the first engine start of the day. Is there a diaphragm or check valve inside the pump assembly? I'm thinking maybe something in there has failed.
Thank you

 

I'm 80% sure that there is some sort of a check valve in the pump .....hopefully some one else will know for sure.
from what you said above, the regulator seems to be working.,also I know you said the filter was new a while ago, but a new one wont hurt anything. also a bottle or two of fuel injector cleaner wont hurt either.

 

Thank you. Id like to think that since initially I only touched the fuel pump the problem would stay there. I ordered some kingsborne wires, I suppose I'll throw a filter on as well. Its unsatisfying having to do a 3 second count before starting.
If it is the pump assembly does anyone know a cheap replacement? I have a non sai.

 

Check valve is in the fuel pump pickup where sock is attached. When your checking the pressure at the Schrader valve it's not rail pressure but line pressure. So with that in mind check for any leaks in your line, maybe at the filter can or sending fuel line at pump attachment. Leaking or stuck closed injectors make a motor run unbalanced and with less power. You'd notice. Those are easy to find by eyes on spark plug (wet/dry) and injector plug pulling. Another point is the fuel rail itself is made out of less than ideal material (should be stainless) that rots (rusts). I've blown my rail out a few times because I found rust scale in the injector screens. The FPR has a plunger/pintle arrangement and if it's not fully seating it will allow pressure past it. Instead of fuel I use air to pm my fuel system.