1993 Bronco Fuel Pump ????

[tmbkb]

Hey guys - I have a question.............

Thru tons of diagnostics, my fuel pump seems to need replacing...........truck will start and run just fine, and then when it is shut off for 5-30 minutes, it will not start. Testing shows the pressure is about 17-19psi. Should be about 35psi. Natch this is a KOEO test. Previous tests when truck is starting just fine, KOEO pressure is 35psi and KOER is 47psi.

I let FORD test this truck and they said that it is the fuel pump that is causing this prob. Tested the relay and it is good, the 20A fuse in the PDB appears to be ok. Are there any other fuses that could be shorting out???

Anyway - question is - should I use a motorcraft pump assy or is there another suitable mfg for this.

any words of wisdom will help.

thanks

 

[Seabronc]

"You get what you pay for", you might want to do this while you are replacing the pump. http://broncozone.com/forums/index.php?showtopic=12329

Good luck,

>-

 

[tmbkb]

"You get what you pay for", you might want to do this while you are replacing the pump. http://broncozone.com/forums/index.php?showtopic=12329
Good luck,

>-

I saw ur thread earlier and am going to do that. Know that u get what u pay for. Is motorcraft the best way to go. Just looking for some advice.

thanks

 

[tmbkb]

How long does it have to stay off before it starts & runs fine, and what's the pressure during cranking THEN?
This doesn't sound like a pump problem to me - maybe debris in the tank, or a bad shuttle valve, or something on the engine (coil, TFI, ECT...).

BTW

I've also done an access panel article with lots of pics & measurements:

thanks for the reply.

Coil, TFI, IAC was replaced. TFI did test bad, and coil was original.

New cap, plug wires. Cap looked really nasty and wires were really old. Always have spark.

Sometimes when 1st turned off, PSI rises to 57; later when wont start, PSI is around 18. Every time the key is turned, u can hear the pump cycle (go on); When I 1st tried to start the truck today around 10AM, pump would cycle but no start; then it started. Drove to destination and turned off. About 2PM, pump would cycle but no start; then after 2 or 3 times, truck started. I believe now that heat soak has nothing to do with this problem as I have the problem in the AM after sitting all night.

It really appears to be fuel problem and not spark problem. Also, there are never any codes to relating to any problem.

Any thoughts.

thanks

 

[tmbkb]

How long does it have to stay off before it starts & runs fine, and what's the pressure during cranking THEN?
This doesn't sound like a pump problem to me - maybe debris in the tank, or a bad shuttle valve, or something on the engine (coil, TFI, ECT...).

BTW

I've also done an access panel article with lots of pics & measurements:

Here's the latest scoop: I have put a pressure gauge on the fuel rail and have left it there for testing.

1. When sitting Overnight the pressure drops to about 13-17psi. I dont know if this is normal or not. In the morning, engine cranks but no start. Pressure remains the same. Absolutely no gas odor or gas dripping anywhere.

2. I then ground a lead from the FP self test connection to run the pump continuously. Pressure jumps up to 42psi. Engine cranks and on 2nd crank engine starts. I then remove the FP ground and engine runs just fine.

PSI remains steady at 45.

3. When I turn the engine off, the pressure steadily climbs to about 62psi and remains there. I have not stayed and watched the pressure gauge to see how long it takes to drop. Engine off for 5 minutes and will start just fine.

4. After engine has been off for a while, engine will not start and pressure is about 17psi. There is absolutely no gas odor and no gas drippings visible or felt.

5. Put the FP ground lead on and run pump and engine starts right up. I immediately remove FP ground.

Steve83 - any thoughts or ideas.

thanks

 

[AdamDude04]

I thought mine was the fuel pump.. but turns out it was the ECT sensor. A heck of a lot easier to replace than a fuel pump.

I was also going to do the fuel pump access pannel..but decided to wait. However I may do that soon..fuel pump was replaced in 93.. I got nearly 20yrs on this fuel pump. Going to ride it out...