Ive swapped my 89 305 TBI for an 89 350TPI MAF style....i have a serious problem. I replaced the fuel pump with a new high pressure one. When i turn the key I can hear it prime but have 0 pressure at the fuel rail. At certain points I can see it dribble out of the shrader valve when i push it with a screwdriver. When I disconnected the ruber line from the metal line leading to the tank and turned the key, it looked like a water fountain, but still didnt seem too pressurized. I have 2 theroies to the problem.
1)Bad fuel pump, and whoever manufactured the thing is gonna get a kick in the face. This makes no sense because it primes.
2)The VATS is shutting down the fuel pump because I have 3 differant components. The computer is from HAWKS, the key is from my car, and the PROM and engine are from an 89 TA. Any thoughts here guys?
Thanks,
Steve

 

The VATS isn't the problem, if it didn't prime the VATS is the last thing I would check.
Assuming the pump and the shrader valve are good, no pressure at the shrader valve indicates that the fuel is not reaching it.
Disconnect the inlet rubber hose section between the engine and the frame, clamp a piece of rubber hose to the end at the frame which comes from the tank into a container, prime the pump if there is flow then, there is blockage some where beyond that point and the shrader valve.
Time to disassemble and clean the shrader valve, fuel pressure regulator, and fittings.

Be sure to have rags around the connects to catch any fuel in the lines.

 

The pump does prime but it is not giving much pressure. There is flow at the fuel line connected to the frame and at certain points it would just dribble out of the shrader. I will take it all apart and clean it and hopefully that solves the problem but if it is not do you have any idea what could be signalling the fuel pump to stop pumping? Thanks

 

the pump runs for (i think) two seconds each time the motor fires. The pump also primes for three seconds each time the key is trigger. The prime relay is a stand alone system from what i understand. It could go bad but i havent heard of it yet. More than likely it is you Fuel Pressure Reg. If it was sitting in the fuel rail on some old fuel rail for a while with no fuel in it i can almost guarntee that diaphragm dried up and blew to pieces the first time it got 50 psi of fuel to it.
Disconnect the fuel return line(smaller of the two lines runing up to the rail) and block it off. If the system primes and pressures then u prolly just need a regulator.
Pull the bell on the regulator and take a look at it. Make sure you have a replacement on hand. You can always return it to oreilly if you dont need it. If the diaphragm is torn or the little disc isnt spring loaded anymore, replace it, its prolly fixed. If the diaphragm has many peices of rubber missing you prolly ought to pull the fuel rail to make sure theres no debris in front of the injectors too. While they're out, i think there are some methods for soaking injectors to clean them. Check it out. Cars love fresh, clean injectors. Blow through the rail with compressed air and clean it all out. Put it all back together. You shuold replace all the injector orings at this point and the orings in the fuel lines. The injector orings are sold in pairs @ orielly for .99 each. The fuel line orings are 3.49 for the two different sized lines. The regulator is a special order part that runs 73.99(~$4). The Intake runner gaskets were like $13 and they had them in stock by chance. The fuel pump is special order also. Make sure you get the right one!!!! They gave me the low pressure pump the first time. It can cause a similar prob because you only get, you guessed it, 22psi.
Need anything else? holler.

 

Thanks for all the info. I took the entire fuel rail assemply apart and cleaned it. The o rings are new because the injectors are brand new. The regulator seems to be ok. Its still spring loaded and the diaphraghm is still in one piece. I soaked it in gas to freshen it up a little. i reassembled the whole thing and I have made no progress. Now I found out that i didnt put a pulsator on the fuel pump when i changed from the low pressure to the new high pressure pump. Do you think this could be causing my problem? Thanks again,
Steve

 

This is a 350 TPI, right?

If you didn't substitute a short piece of hose (should have come with the new pump) for the pulsator, yes, that's the problem.
However I don't think you left out such an important piece.

Have you disconnected the return line and checked for flow?
Have you checked the gauge? use it as a tire pressure gauge.
Shrader valve, is it good?

BTW I haven't read anywhere that you've cranked the engine.

There doesn't seem to be any obstructions in the system, beginning to look like a bad fuel pump.
You might want to use a standard gauge connected to the supply line where you know you have flow and see if there's pressure there, and how much before you condemm the pump.

 

You can jumper power directly to the fuel pump via the 'G' terminal in the ALDL connector inside the vehicle. This may help you diagnose the problem more easily.

 

Is there a possibility they just sold yuo another TBI pump ?

 

i read the instructions for the fuel pump and sending unit and new fuel pump and surprise surprise they say the pulsator is not included....im beggining to think that is the problem. there is no blockage in the entire system, shrader is good, and it primes so it is getting power. what do i do with the G terminal to get the fuel pump to run? just plug a positive from a battery into it and connect the negative to a ground source? Thanks again for all the replies guys.
----------
BTW, i have cranked the engine, it is a 350 TPI and the fuel pump is a brand new replacement from carter for the 350 TPI

 

I dont have a pulseator on mine. Just a peice of hose that connects the fuel pump to the hard line of the sending unit. Did you do that? If you didnt bridge that gap, then no fuel presure. But you would have LOTS of noise in the tank.

Go ahead and disconnect the main inlet line just before the motor, and hook a fuel pressure guage up on the line that goes back to the tank. Jump the fule pump like Vader said and if you dont read any fuel pressure there, then it is either crushed or otherwise obstructed fuel lines or a bad pump or, least likely, bad power to the pump. If the pump does prime, then it shuold have good power.
OOOhhhhh, a funny(tear) story. The fuel line segment that came with my fuel pump wasnt heavy enough to handle the pressure. It burst one month later even with a completely dead fuel pressure regulator. I have since installed a piece of braided 3/8 emmissions hose with metal hose clamps(instead of the plastics that come with it). That could happen too.

 

Just supply the 12v from any hot at all times source to the "G" terminal with the key off, the pump is already grounded at the tank.

 

Well it looks like im gonna have to drop the tank and find out what i have. I know i dont have a pulsator but there is always is the possibility that i went into the project unprepared and screwed something up. im going to try the power idea to see what happens. Any other thoughts? I really appreciate the help guys. This may be a stupid idea but does anyone think that 4 gallons couldnt be enough fuel to reach the pump? The tank was COMPLETELY bone dry when i put it back in and i filled it with 4 gallons. Thanks again guys

 

Probably enough, but I'd suggest another 4 gallons, now that you know about the "G" terminal emptying the tank is a snap.

 

If you reused the short piece of rubber tubing instead of a pulsator valve, thats your problem right there, the rubber tubing has probably burst under the higher pressure, it can only support 12 to 15 lbs not 45. Replace it with a puslator valve or some high pressure FI hose.

 

Thanks alot i finally gave in and dropped the tank and sure enough it burst. Engine runs great now. Thanks again.