Dude, those fuel lines are toast. You NEED to replace the rubber on them!

And yes, it's supposed to be 14.5PSI with the pump running. If you prime, how much does it get to?

Did you bypass the ASD yet?

Here's a picture of a matching relay; you want to jump the 30 to the 87 terminals. That will run the fuel pump (and enable power to the injectors and the coil; don't leave it jumped!)

It should pump up to 14.5psi quickly. If not, before I pulled the pump (even though I'm positive that's the problem!), check and see if there's any gas odor at the vacuum line to the regulator. If there is, swap that first; in any case, also swap the fuel filter on the frame rail under the driver's seat.

http://www.texasindustrialelectric.c...0332209138.asp

RwP

 

The fuel filter is not clogged, i already blew in it.
There is no matching relay (the thing on this link : http://www.texasindustrialelectric.c...0332209138.asp ) in the Fuel relay emplacement (tell me if you understand here) IS THAT IMPORTANT OR NOT NECESSARY

- Id like to ask if the setup to test gas pressure is ok because i was getting around 2-5 psi (which i think isnt enough)

I'll get a new pump and install it and see if it goes better. If it doesnt work then i don't know what to do hahaha

Thanks for the help, it's really appreciated !

Jordan

 

Not the "fuel pump", but the "ASD" position.

But then again, on a 1991, it may be different.

That's why I'm suggesting running the pump by itself.

You can cheat a bit .. turn the ignition ON (but NOT TO START!), leave it for ten seconds, turn it off, leave it for ten.

Do this three or four times.

See if the fuel pressure comes back up to 14.5 or not.

Unless you've changed the fuel filter, I'd change that ALSO.

I did discover - the 92/93 filter is straight through, the 87-91 requires a 180* bend on the inlet hose. Be sure to test that 180* bend ALSO. And if you replace the filter, rerun the lines to use a 92/93 filter.

RwP

 

I don't really get what you want me to do... You want me to remove it ? Or place it somewhere else?

Jordan

 

I can't make it any clearer in English, but I'll try.

Remove the ASD relay.

Take a piece of wire about, oh, 10cm long.

Strip both ends.

Put one end in the #30 position in the socket.

Put the other end in the #87 position in the socket.

See if the pressure builds to 14.5psi / 100kPa .

Also, see how quickly it builds to that.

RwP

 

If you don't want to do that, ignore the relays.

Turn the ignition to ON (but not to START!) for ten seconds, turn it off, and repeat this three or four times.

That is , ON ten, OFF ten, ON ten, OFF ten, ON ten, OFF ten.

At that point check the pressure, is it 100kPa/14.5PSI?

RwP

 

Alright , i'll test that asap.

But, could you tell me if my gas pressure test setup is OK like that? I'm NOT a mechanical guy at all... I just do that in free time !

Jordan

 

Yep, that's how you test it on our trucks.

RwP

 

UP, I tested gaz pressure, i only get 8 psi of pressure, it goes right to 8psi real quick

Jordan

 

Spec for the TBI units is 14.5PSI; I'd say you've got either a bad pressure regulator or a bad pump or filter; possibly all three.

RwP