anyone know about fuel system on Late model Bronco?

I've been chasing a no start problem for most of last week. Motor turns over, good speed - this was a 'sudden' change. The truck was running OK, parked it for a day or two. Went out to start it and it wouldn't go. Tried it a few times before figuring that something was wrong.

I've check shut off switch - its OK, checked and changed out TPS and IAC - both were original to the motor and TPS is in a weird spot and IAC was "iffy", so decided to install new. To be safe while change out the sensors/inputs, I disconnected the battery - the bad thing about that is it probably means I can not pull any computer codes. Checked for blown fuses: both under dash and underhood, didn't find anything that was obvious.

I'm down to 1.) bad fuel pump. 2.) bad relay 3.) bad PMC. Changing the computer or fuel pump are expensive - saving them for last resort, seen too many people swap the computer for no good reason - seems most shops want to start there, ignorance or greed?

I found someone that suggested how to test the fuel pump energizing circuit but I am unable to physically perform that test. So, thats on the back burner right now too.

OK, history lesson over, on to the meat in this sandwich. I checked my dusty, trusty Chiltons for 88 - 96 bronco/f150, but it doesn't have the detailed information I need to locate the last piece of the puzzle. So, my question(s) start with; does anyone know which relay controls the Fuel pump circuit for a 1995 Bronco.

Can you guys think of any step I missed or point out the correct relay to check, change, replace - are the relays 'self-healing", or resetable? By this - I mean once tripped, is the relay destroyed? Can you reset them somehow or does it need to be replaced?

Might me easier for me to talk you through but. When turning key on you should hear fuel pump for 3 seconds. If you dont then you need to locate the fuel pump and eec relays under hood by left hood hinge. If it is 88 ish then look to make sure really are not just laying there filling up with water. Check for any green or broken wires. While holding or touching relays have some one else turn key to on position. You should feel both relays click and in 3 seconds one will click again. Let me know what happens.

Originally Posted by gbic1

Might me easier for me to talk you through but. When turning key on you should hear fuel pump for 3 seconds. If you dont then you need to locate the fuel pump and eec relays under hood by left hood hinge. If it is 88 ish then look to make sure really are not just laying there filling up with water. Check for any green or broken wires. While holding or touching relays have some one else turn key to on position. You should feel both relays click and in 3 seconds one will click again. Let me know what happens.

No - its a 1995. They changed things around a lot from year to year.

On the 1995, there are 2 boxes under the hood, the larger one has fuses and large size fuses, the second one is smaller; long and narrow - it has space for 4 relay sockets, two of them are filled (meaning they have relays plugged in), the relays are about 1 inch cubes.

The fuel pump on the 1995 model is not the same, it has a single pump, of the intank design.

Glad you added year but it still works the same. Are relays clicking? Ground the light blue and orange wire at the self test connector and turn key on. fuel pump should run. if not it may have bad pump but you can now test power to pump by your self.

Originally Posted by gbic1

Glad you added year but it still works the same. Are relays clicking? Ground the light blue and orange wire at the self test connector and turn key on. fuel pump should run. if not it may have bad pump but you can now test power to pump by your self.

Thanks for the tip and the work around test. I'll give it a try.

My bad: I could have sworn I mentioned the year in the initial message - I try very hard to do that, 'cause it really chaps my hide when I want to or try answer a question and the guy doesn't provide the basic information needed to give him help.

Normally you posts are excellent so was not really trying to rub it in. I am having problem uploading the wiring diagram. SO if you want to send me privately you email addy I will send it. This fuel system is my specialty. I currantly own a 88 Bronco with 5.8 and a 93 F350 with 5.8.

The Inertia switch, although still in good physical condition is a concern in may newer and older bronco's here in my neck of the woods.

It was the same on the Rangers for a while also.

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Yeah, the inertia switch can be a gotcha once in a while. I would locate the relay (using the legend on the box lid or tracing the wire colors) and just jump it. If the pump runs the issue is before the relay (power or control) or the relay itself. If it still doesn't run, the issue is after the relay (power, I.S., pump, grounds). You can jumper each item to rule it out.

David

Problem was cured. Fuel pump was defective, this took care of the no start problem. Other issues cured along the way: too high idle - IAC, continued Check engine light - EGR valve obsruction, three is one other issue which was uncovered on the way, that is still undiagnosed. But the truck is running, and running better than it has in a while, I'm actually finding a silver lining in this cloud.

That's great news! Please make sure that if you have a frame mounted pressure pump that you ensure every 6 months or so that the Electrical connections (if the male female blade type) to ensure they are tight.

They like to get warm with use and lose their grip then start arcing and giving poor pressure up top because they turn on and off with every other bump in the road.


FE