truck died...help!!!

mutang02 · #1 (**permalink**) 03-03-2008, 05:41 PM

hey guys I have a 1988 bronco with a fuel inj 302. I was driving it down the freeway yesterday at about 70mph when the truck completely died. It was running fine until it just felt like someone turned the key off. I figure it is fuel pump related, but I have never heard of one just going out after running fine. I replaced both the fuel pump relay and the eec relay. I can start the truck with ether, so I figure it isnt the ignition. Also when you turn the key on the fuel pump never primes. Anyone know of anything else to check before replacing the pumps themselves. thanks

NumberDummy · #2 (**permalink**) 03-03-2008, 05:49 PM

Quote:

Originally Posted by mutang02

hey guys I have a 1988 bronco with a fuel inj 302. I was driving it down the freeway yesterday at about 70mph when the truck completely died. It was running fine until it just felt like someone turned the key off. I figure it is fuel pump related, but I have never heard of one just going out after running fine. I replaced both the fuel pump relay and the eec relay. I can start the truck with ether, so I figure it isnt the ignition. Also when you turn the key on the fuel pump never primes. Anyone know of anything else to check before replacing the pumps themselves. thanks

Usual cause: Ignition module and/or stator (aka pickup coil) inside the dizzy.

Where is the module, on the dizzy or on the left fender inner apron (prolly on the dizzy)? Ford used both types, depending on the engine size.

If on the dizzy, you'll need a thin shanked TORX driver to remove it.

Dizzy Module: E43Z-12A297-A (Motorcraft DY-425) Marked: E3EF-12A297-A1A or A2A.

E5PZ-12A112-A .. Stator (Motorcraft DU-30-A)

mutang02 · #3 (**permalink**) 03-03-2008, 06:03 PM

the ignition module would cause the fuel pump not to prime? is there a way to test the module before replacing it? I am trying to spend as little money as possible, I close on my first house friday, and will be eating nothing but ramen as it is. thanks

andym · #4 (**permalink**) 03-03-2008, 06:16 PM

If the ECM doesn't think the distributor is turning (the hall effect sensor inside the distributor tells it so) then it won't turn the fuel pump on.

So yes, it can cause this. Also if the ECM itself died it will cause this behavior. Can you pull codes from it? If so, the ECM is probably ok.

You could also have a wiring problem somewhere between the relay and the pump.

mutang02 · #5 (**permalink**) 03-03-2008, 06:43 PM

but the pump should prime when you turn the key on before the engine starts rolling over.....before the distributor turns correct?

andym · #6 (**permalink**) 03-03-2008, 06:56 PM

You know what... you're right. I must be asleep over here.

It's either a dead pump (a multimeter at the pump will tell that for sure), a wiring problem (open circuit, loose ground) or a dead ECM.

mutang02 · #7 (**permalink**) 03-03-2008, 07:05 PM

thats cool I was just making sure I am not crazy. can i just unhook the wires from the pump, and see if they are getting juice with the key on? or does it only send juice for a second until you start to try to roll the engine over? also the truck also has what looks to be a second pump on the framerail....is that stock?

blue beast · #8 (**permalink**) 03-03-2008, 07:10 PM

I had a wire get worn through on mine, The wire bundle was touching the alt bracket
and it was a bear to find since I had to pull apart the loom and undo all the tape
and finally I found it. So bust out the multimeter and a safety pin and trace the wire
for the fuel pump start at the pump itself and stick the pin in every 12 inches until
you get voltage. You can also just inspect all the wiring where it comes into contact with any metal part. Don't just start throwing parts at it get a DVOMeter and test
test test tell us what you get and we can give you other stuff to test. Unless you
like wasting money.

andym · #9 (**permalink**) 03-03-2008, 07:10 PM

Yes that's how you can test to see if the pump is getting power.

That is a stock setup. For EFI trucks up until 1990, there was an external high pressure pump on the driver's side frame rail roughly under the front seat and a low pressure pump in each tank. In 1990 they went to a high pressure pump in the tank.

mutang02 · #10 (**permalink**) 03-03-2008, 08:25 PM

alright I will do that after work tommorrow thanks a ton guys

Encho · #11 (**permalink**) 03-03-2008, 08:45 PM

Before anything else, check the fuse box (manual in hand), it might be something as simple as that.

mutang02 · #12 (**permalink**) 03-03-2008, 09:37 PM

i already checked every fuse just to be sure, It actually ran good enough off ether to load it on the trailor, granted it took 3 cans......

Bimmerboy1989 · #13 (**permalink**) 03-03-2008, 10:48 PM

The ECM is turning on I assume? The ECM relay controls the ground to the fuel pump relay. If the ECM relay doesn't come on the fuel pump doesn't come on. How about a faulty inertia switch?

blue beast · #14 (**permalink**) 03-03-2008, 11:52 PM

Don't waste your money on Ether(not really ether anymore!!) Just use a propane
torch (not lit) and run it off that. You can start it, diagnose vac leaks, loosen seized
hardware and burn the sucker to the ground if it makes you that mad!! All with propane
If the inertia switch is faulty please don't just wire around it!! At least put a toggle
and mark it FUEL PUMP in big letters so if you wreck out and a flame thrower is issuing
from your grill they will know to cut that switch!!

mutang02 · #15 (**permalink**) 03-04-2008, 06:18 PM

alright guys, checked the wiring going into both pumps, and there is no juice at either one. however there is juice coming out of both the fuel pump relay and eec relay. There are four wires coming out of each relay and three of the four on both are hot. does that leave me with a possible bad wire somewhere? Could it still be the inertia switch? and if so where is it located?