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Having starting trouble, looking for advice.
87 150. Truck sat for a few months, never had issues starting previously.
Engine turns over won't start. Pumps don't prime with key rolled forward.
Replaced fuel pump relay.
Battery is good.
I can jump the relay and activate tank and HP pumps, they will not prime by key.
Inertial switch seems okay (good way to test?) white button.
I've cleaned and checked grounds.
Not familiar enough with the system to work backwards effectively.
Any and all advice is welcome. Thanks for listening.
Having starting trouble, looking for advice.
87 150. Truck sat for a few months, never had issues starting previously.
Engine turns over won't start. Pumps don't prime with key rolled forward.
Replaced fuel pump relay.
Battery is good.
I can jump the relay and activate tank and HP pumps, they will not prime by key.
Inertial switch seems okay (good way to test?) white button.
I've cleaned and checked grounds.
Not familiar enough with the system to work backwards effectively.
Any and all advice is welcome. Thanks for listening.
Have you had any previous issues with the key cylinder?
When you rotate the key to the run position, do accessories like wipers, heater fan, radio, etc work?
Stand beside the truck with the hood open and turn the key to the run position. The fuel pump relay and the ECM relay should click on. After about 2 seconds, the fuel pump relay should click off. During that 2 seconds, you should hear the fuel pumps running.
There are blue capacitors on the ECM circuit board that are known to fail. The ECM is behind the driver's side kick panel, and pulls into the cab for removal, after unplugging the 60 pin harness connector by loosening the 10 mm head bolt, in the center of the connector.
There's also a bracket connected to the ECM housing behind the kick panel.
Here's the thread where I replaced my capacitors Relay chatter after turning key off - Ford Truck Enthusiasts Forums https://www.ford-trucks.com/forums/1...g-key-off.html
Also, make sure these two grounds are connected to the battery negative terminal, and if you have this style of battery terminals, the terminals could be your whole problem. They cause issues with loose connections and corrosion.
Thanks. I'll have a look today.
The truck is in pretty good shape, I keep connections clean. Never had a problem with the key cylinder, lights, horn, wipers all in working order, nothing loose or sloppy.
I don't have any relay chatter, in fact I can't be 100% sure either of the relays are cycling with the KO. I'll have to put a hand on them to be sure, currently I don't believe they are.
I do remember having a possibly related problem when the truck was running before it sat. It would occasionally sputter and quit while sitting at idle, like it was fuel starved. Possible whatever was failing then has quit for good.
Relay chatter was the symptom with my truck, but there are plenty of instances of no starts caused by malfunctions of the circuit board. The board controls the fuel pump relay.
Well, went out this morning, inspected some wires, jiggled a few things, plug and unplug and got the relay to pulse, pumps primed and the old truck started right up. Not surprised, pretty reliable, suffering from aging electronics. Pleased but also disappointed it was such a simple fix...
Well, went out this morning, inspected some wires, jiggled a few things, plug and unplug and got the relay to pulse, pumps primed and the old truck started right up. Not surprised, pretty reliable, suffering from aging electronics. Pleased but also disappointed it was such a simple fix...
Glad you got it.
I use anti oxidant on anything I unplug.
[QUOTE=TheARC;21701603 Pleased but also disappointed it was such a simple fix...[/QUOTE]
Jiggling a couple things does not mean it's fixed. Let alone a simple fix. It's an assumption at best that anything you did caused the engine to start. I've worked on enough intermittent issues that just because you kicked the tire means it's fixed. Many times, it has nothing to do with your problem. Just have AAA on speed dial.
Well, went out this morning, inspected some wires, jiggled a few things, plug and unplug and got the relay to pulse, pumps primed and the old truck started right up. Not surprised, pretty reliable, suffering from aging electronics. Pleased but also disappointed it was such a simple fix...
Look for loose and corroded terminals at the EEC and fuel pump relays. I had that problem on my ‘89. It would cause a no start problem or the engine would shut off while driving
. Have "fixed" many vehicles with a turn of the battery terminal. 
