No Spark, No Fuel, No Codes, No Nothing 91 Bronco SD 300

rustyoldfords

Active member
Howdy all. I'm just about at my wits end with my girl's truck. She was leaving work the other day, fired the truck up and let it fast idle. When it kicked down to slow idle, it shut off. Didn't stumble or anything, she said it acted like she turned the key off.

Being very new to EFI (only other experience was swapping this straight six into this truck due to a tired 351) I followed some troubleshooting steps I found online. Had power everywhere it was supposed to be, so I changed the TFI module. No luck. I also bought a new PIP sensor, but I can't get the gear off the distributor to change it. I'm wondering if this is even the right direction as it has no fuel at the rail either.

When I turn the ignition on, I can hear the relays under the hood engage, but the fuel pump never does. I can however remove its relay and hotwire it and make it work.

Furthermore, I never get a check engine light throughout the whole process, and plugging in the tester for a KOEO test, the truck acts like the testers not even plugged in.

Any suggestions or kicks in the right direction would be greatly appreciated.
 
rustyoldfords":2s7me27d said:
......

When I turn the ignition on, I can hear the relays under the hood engage, but the fuel pump never does. I can however remove its relay and hotwire it and make it work.

Furthermore, I never get a check engine light throughout the whole process, and plugging in the tester for a KOEO test, the truck acts like the testers not even plugged in.

Any suggestions or kicks in the right direction would be greatly appreciated.

Fuel pump dead upon key being turned means ECM dead.
No check engine light mean the ECM is dead I belive
Tester being dead is the same also.
 
That's what happens when the ECM goes bad: nothing. Everything drops out and the truck is dead. Happened to me at least once with my 87 F-150. Just freakin' stopped. Fortunately it was in a center/turn lane of a city street and not on a highway.
 
Right on. Thanks for the help all. I will begin the hunt for yet another ECM for this motor.

My understanding is that any 91-94 ECM for a 300+E4OD will work, correct?

The ECM that went in it from the swap was from a 93 Econo with this set-up, and it worked. I'm wondering if that isn't why it cooked though.
 
It was indeed the ECM. I've compiled the following list of ECM part numbers which should work with all 91-93 300/E4OD combos:

F1TF-12A650-AGA
F1TF-12A650-ALA
F1TF-12A650-ANA
F1TF-12A650-ARA
F2TF-12A650-AXA
F2TF-12A650-AXB
F2TF-12A650-VA
F2TF-12A650-VB
F3TF-12A650-ABA
F3TF-12A650-ABB
F3TF-12A650-ZA
F3TF-12A650-ZB

I personally have used the F2TF-12A650-VB and F3TF-12A650-ZA and can verify that both run a 91 E4OD with a 93 300 L6.

P.S. These are all standard emissions computers, sorry CA folks.
 
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