I’m stumped on no start

[9t3lightning]

Ok group
My 1990 wagon was sitting for almost 2 years , with occasional starts
Well now it won’t start , changed the fuel pump twice( thought maybe the first one was bad) changed the filter, and regulator ( what a joy to get to last screw ) also have power at injectors when car is on
And still not starting , it will start with starting fluid no problem .
Now both pumps were also only showing about 5-10 lbs of pressure
But seems like there’s more when the schrader is pushed in.

What can i try
Next ??


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[kishy]

I would agree that you've got it narrowed down to a fuel issue (e.g. not a spark issue).

Fuel works like this:
You turn the key to run, and the ECM powers on the fuel pump relay for a couple seconds to prime the pump.
The pump sucks gas out of the tank and pushes it into the fuel rail, where it waits for the injectors to open to let the gas into the cylinders.
The computer will power the relay again when the engine starts to turn, and will continue to keep the relay powered as long as the engine continues to turn.

You need 35+ PSI (spec is 35-45) for the pressure to be enough to make a pattern that atomizes, and supplies enough fuel (e.g you need both fuel pressure, and to flow enough volume to keep that pressure up once it's running).
You're definitely too low and this is why it won't run.

Low fuel pressure has a few possible causes:

-electrical problem preventing the pump running adequately to produce pressure.
Since you've been at this for a while, I'm skipping to a little bit more advanced and dire methods:
If it were me, I would use a battery (such as a booster pack) and some test lead wires to directly power the fuel pump at the connector above the tank under the car, and check pressure at the fuel rail while the pump is running in this arrangement. You should see your 35+ PSI. If you get your 35, the problem is "upstream" of that connector. If you still don't get your 35, the problem is either not electrical, or is electrical "downstream" of that connector. e.g. the wiring between that connector and the fuel pump hanger, or the wires that are part of the pump hanger itself.

-bad pump. The probability of this being your issue is very low.

-low fuel level in the tank. If the level is just high enough for the pump to pick some of it up, but also pick up air, you'll get little squirts of fuel but not enough to do anything useful. Silly question, but you're sure there's at least a few gallons in there, right?

-restricted fuel line, such as a kinked nylon line (perhaps occurred during removal of the tank? the "rubber" lines at the tank are actually nylon lines inside of rubber sheathing), or steel line plugged with debris such as rust flakes/chunks, or possibly degraded chunks of the rubber line from inside the tank, if it was falling apart previously. I'm assuming you replaced the line inside the tank when changing the pump. If not, it is also suspect as a possible leak point preventing pressure building.

[9t3lightning]

Thanks for the response
I forgot to mention
It seems like I hear the fuel coming up the return line, or i hear what sounds like a leak but it’s definitely on the drivers side near the fuel line.
But after disconnecting the return line at the drivers side rear wheel
And turning on the key gas is coming from the metal line and not the tank so that rules out the pump being wired wrong ?
Only thing i don’t understand is in the shop wiring diagram it states connector c400 for the fuel pump The halves are reversed?? What is that meaning ?


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[kishy]

If with the return line disconnected, the fuel is coming from the front of the car rather than the rear, yes, the fuel is flowing the correct direction and the pump polarity should be correct.

This also tells us that fuel is getting from the pump, to the fuel rail, through the regulator and back to the tank.

I believe that language probably means the "male" and "female" ends of the connector are reversed, e.g. on a sedan perhaps the male terminals are on the car side and the female are on the tank side, and on a wagon the reverse would be true. Most likely this would be done to prevent the factory mixing up the harness for a sedan vs a wagon. This is all just a guess.

I just looked through my photos and see that on my 84 Town Car, the female plug is on the body of the car, and the male plug comes from the tank. I wasn't able to find an equivalent photo of my wagon but I think I remember it being the other way around.

[sly]

If the fuel pressure regulator is not restricting any flow at all, you won't create much pressure either. So as long as the fuel filter is known good (new), the fuel is known good (no water), the fuel lines are not crushed at any point or broken, it's probably the fuel pressure regulator.

[WagonMan]

I put a new fuel pump in my 89 Colony Park. It won't start unless I cycle the key three times. Then it starts right up. I assume you hear the fuel pump run for a few seconds when you turn the key on? WagonMan

[9t3lightning]

I put a new fuel pump in my 89 Colony Park. It won't start unless I cycle the key three times. Then it starts right up. I assume you hear the fuel pump run for a few seconds when you turn the key on? WagonMan

Yes I here it
Come on , and even jumped the fuel pump prime connector up front to
Make
Sure I hear it run


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[9t3lightning]

If the fuel pressure regulator is not restricting any flow at all, you won't create much pressure either. So as long as the fuel filter is known good (new), the fuel is known good (no water), the fuel lines are not crushed at any point or broken, it's probably the fuel pressure regulator.

Well I changed all three items
How can i test the new regulator to see if it’s faulty ?


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[9t3lightning]

Also
Hooked up a fuel pressure gauge at the schrader valve and after cycling the key a few times from both fuel pumps that i tried now the most pressure i get is 10lbs.

This is driving me nuts


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[WagonMan]

Maybe try hooking up a line on the output end of the fuel filter and check fuel pressure there. It would tell you if there is a problem before the filter or after the filter. WagonMan

[9t3lightning]

Hahaha
Getting ready to do that now [emoji16]


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[sly]

You should get well over 50PSI direct off the filter if you dead head it. I think the pumps are rated for 80-90psi, but I'm not real certain on that. You should definitely get more than 40PSI since that's the high level during actual running.

[9t3lightning]

Ok an update
I get 90 psi direct from the pump line before the filter, changed the filter again just to make sure and get 46 psi at the bottom of the motor at the quick connect. But when I hook it all back up I get 10 psi at the schrader valve.
I also blew out the line from the bottom of the motor connection all the way to the top of the motor at the return line to make sure of no blockage.
So this is crazy, and on top of it
The fuel pressure regular hisses when the pump comes on??? I’ve already changed it and it still hisses, put the old original one on and it hisses too??
What could cause that?
And with the schrader valve right at the point of the fill line coming from the pump u would sware I should have presssure….. heeeeeellllp me


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[9t3lightning]

Forgot to add this
When I had the lines open on the motor, and pressurized the line from the bottom of the motor with air and kept my thumb over the return line connection the pressure gauge would register like it has fuel pressure but just with air. Crazy


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[friskyfrankie]

Hissing? Possible vacuum leak in the area of the valve for the fuel regulator?