90 Bronco II fuel pump replaced but won't start

[joshshields9]

My 1990 Bronco II was starting with a fair amount of difficulty, especially when cold, so I decided to replace the complete fuel sending module with a brand new one.
Now that I have replaced it, however, it will not start at all, even with starter fluid.

I already purged the lines by taking out the fuel pump fuse and cranking the engine, but this did not help. I can also hear the fuel pump running when I turn the key.
I checked the fuel rail pressure by pressing on the outlet with a screwdriver. The first time I pressed it, some fuel flowed out, but after trying to start the engine a few times, nothing comes out at all. This makes me think that the initial pressure in the line was just residual.
I double checked the electrical and fuel line connections, but the electrical connector is all the way on, and the lines are snug and connected with the 90 degree hose going onto the vertical tube of the fuel sending module and the straight hose going onto the horizontal tube.

I'm not sure what else to check to figure out why the new unit is not delivering fuel even though the old one did just yesterday.
Any help is greatly appreciated.

 

[L\Bronco]

Hey Josh
Does yours have the 2 pump system?
They often have a hi press pump on the frame rail. If not, make sure the plastic line from the sender didn’t get trapped between the tank and the floor on reassembly. (It happens sometimes.)
Good luck
Cheers

 

[joshshields9]

Thanks for the help! I pulled off the line coming out of the fuel filter and had my wife turn the key. Fuel was coming out, so that shows me that everything from the pump to the filter are gtg.

Tomorrow I will take the line off after the high pressure pump and see if that is functioning. If it is then I believe that would indicate an issue with the fuel regulator.

 

[L\Bronco]

Good luck

 

[joshshields9]

Good luck

I've been looking for the high pressure fuel pump and have traced the line from the filter all the way to the pressure regulator. Still don't see it?! Do some models come without it? All the diagrams in the manual have it but I'm simply not seeing one...

Thought I found it for a sec but it was some kind of unit to move brake fluid that looks similar to the hpfp.

Going to disconnect the line at the pressure regulator and see if fuel is good up to there.

 

[Tiha]

In your other thread you said fuel pressure was 0.

Is that still the case?

If the pump is running and pressure is 0, you have blockage, bad regulator. Maybe even injector stuck open.

 

[eddiej]

Hi Josh,
Have you checked to see if your inertia safety switch has tripped? You may just need to reset that.
The older fuel injected Rangers and Bronco II's (88-?) had 2 pumps, a low pressure pump in the tank, and a high pressure pump mounted behind a metal shield on the frame rail just below the driver. A filter was mounted on the frame rail, downstream (after) the hp pump. Early models also had a small fuel reservoir canister prior to the frame mounted hp pump. It is a black plastic canister and a bit larger than a tuna fish can. My shop manual says this was to prevent hp pump cavitation when starting on an extreme slope while low on fuel. Although Fram makes a filter, there is disagreement as to whether or not this reservoir should have a filter in it or not. Our 88 Ranger 2.9 STX did not have a filter in it. The canister does unscrew from the housing, but Warning- The O-ring seal is very thin and fragile.
With all that being said, Have you tracked your fuel line all the way from the tank to the engine to verify a second pump or not? You may be hearing the tank's lp pump, but that won't push much more than 8 psi and you should be seeing about 38-40 at the Schraeder valve if the hp pump is functioning. Also, once you get fuel pressure, carefully disconnect the vacuum line on the fuel pressure regulator and if the line is wet with gas, the diaphragm has ruptured. You'll need to replace the FPR.

 

[L\Bronco]

Although Fram makes a filter, there is disagreement as to whether or not this reservoir should have a filter in it or not. Our 88 Ranger 2.9 STX did not have a filter in it.

They never came with a filter from the factory. In the mid 90’s Ford did a fuel line recall on F-150 and full size Bronco for fire caused by static discharge. You removed the FG-800 inline filter and 2 lines, replaced it with a braided stainless line and installed an FG 848 in the cannister after removing the stand pipe. (Thats why they are available)
Hey Josh, I agree with Eddie, make sure you don't have the 2 pump design before going any further, they definitely come both ways and I cant remember the change over date, sorry. Once you are sure its one pump or the HP pump is not the issue, if you remove the return line at the regulator, and cycle the key it can verify the regulator. There shouldn't be any fuel flow at the return line until the system reaches 48 psi.
If there isn’t any, then check the flow at the supply line. (The bigger fitting is pressure, small is return.)
Hope that helps
Cheers