1987 F150 with the 302

I have a 1987 F150 & it won’t stay running .
We have changed the fuel pump and the tank & the battery & it still won’t stay on !
When you spray ether “starting fluid” it starts but won’t stay running my dad thinks gas isn’t getting to the engine & we are at a stump. Any one got any ideas ?

Did you check fuel pressure?

it’s sitting in the drive way , how would you recommend I check that and if that was the issue how would I fix it ? As of right now it’s not getting gas we have changed the fuel pump the tank the filter inbtween it. The relay , I’m running out of options .

hookup fuel pressure tester/gauge, turn on ignition. our 88 f150 w/302 was injected. 87 was not?

Okay well I’ll tell my father to see if he has one.

Anyone check the filter?

With the key turned to Run (not all the way to Start) pump should run for a few seconds. Can someone hear this, through the open fuel filler tube or maybe under the tank (assuming pump is in tank)?

Yup sure did

Pump is in the tank , we already changed the in-line fuel filter the tank the pump and relay

If you mean the engine will start and immediately die you should consider checking the fuel pump relay ground for the trigger circuit in the relay.

This is a single wire connector next to the Diagnostic Link Connector and will be tan/green or blue/orange in color. Use a test light by probing that connector with the light grounded, If it starts and runs fine then you need to consider a faulty ground circuit inside the ECM

There are other things it could be (ignition module which is a TFI and very prone to problems or a faulty ignition switch. That’s the short form. Hope it helps.

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How long does it run after it starts until it stalls? Is there anything you’ve tried that helps it to stay running longer, before it stalls? If so, what was it, and how much longer did it run? What’s the recent history for this truck? Was it running fine for many months, then just one day a few weeks ago it started to show this symptom? If you’ll allow a guess just based on what you’ve reported so far, it sounds like it is running too lean. So either a problem with not enough gas, or too much air. The air problem is sometimes easier to check. Have you done a thorough vacuum system check, to make sure there are no vacuum hose leaks, and not vacuum operated devices that are leaking? Two vacuum operated devices to definitely check are the brake vacuum booster, and the hvac door actuators, if they use vacuum power.

Some ford engines of that era as I recall had a problematic EGR part. Forget what it is called, but it modulates the vacuum to control the amount of EGR to use. When it fails, it opens the EGR valve too much for the operating condition, which will stall the engine. DPFE is what that part is called I think. But I don’t see that part listed for an 87 F150 302. There is at least one tsb listed for the egr system for your truck. Number 89-18A-9.

Your truck came with either EFI fuel injection or carb. Are you sure you have the EFI version?

If when you first turn the key to start and the engine fires up, as soon as you let go of the key, is that when it dies?
If so, sounds like a bad coil resistor/ballast resistor to me

If it were my 73 Ford 302 truck with mechanical points, that would definitely be a possibility for a cranks-starts-and-dies scenerio. But OP’s truck is an 87 and uses Ford’s electronic ignition system. That configuration may or may not use a ballast resistor. If there is one, it will be in the wire between the ignition switch and the + side of the coil. The starter relay will have a wire attached to it that bypasses the ballast resistor during cranking. The ballast resistor is usually just a short length of wire on Fords, labeled “resistor”. Usually 1-2 ohms.