Pappy Goodwill

2002 F150 XLT, extended cab, 5.4 L, Won't start- no fuel (will run when spraying starting fluid) Wait a couple of minutes after first few attempts and fires right up. No trouble codes on OBD2, Replaced fuel filter, fuel pump relay, PCM relay, doesn't have fuel pump regulator module, replaced PCV valve and all vacuum hoses suspected of dry-rot. Temperature/weather and engine cold/warm make no difference. Roll-over/impact switch connections clean and tight. ?Failing PCM? Is there available software/connectors to diagnose PCM?

Okay, maybe I wasn't clear. (Copy of reply to other user) The engine will crank/turn over/spin. Good starter, good battery. It will "start" and "run" with starting fluid. Well, more sputter than run, but there is combustion occurring with starter fluid. The real mystery is, that when it decides to start, all I have to is "bump" the key and it fires up and and runs smooth as silk. I'm beginning to wonder if my PCM is losing it's mind, or my OBD diagnostic module is losing ITS mind. I REELY don't want to drop $100 on the roll of the dice to see if it is the fuel pump.

white89gt

Did you replace the pump? You only said the relay.

BareBonesXL

Sounds like you're saying that it won't start on the first try after it sits for a while.

That is often a sign of a failing fuel pressure regulator. The fuel pressure is leaking down when it sits and doesn't build back up fast enough. The first few attempts squirt a little bit of fuel, not enough to fire, that vaporizes while you wait. Measuring fuel pressure would tell you.

JCR 56

I think the fuel pump is on it's way out.

BareBonesXL

The other side of the pressure retention is the fuel pump. There's a check valve inside.

Pretty common in old car world for one or the other to be bad, letting pressure drop and the fuel rail to empty itself.

Jbrew

With the pumps,there's a 1 1/2" rubber/silicon tube just after the check that was known to split. It's there to reduce pump to hard-line vibration. They fixed the problem I believe, but if it's an old pump....

dontherogue

On my '99 4.2l, I had an intermittent problem like the one you describe. Then one glorious sunny day .... no start condition. Period. With the tow and new fuel pump complete with labour, set me back over a thousand beans. The pump itself was over $400 and installation about the same (they have to drop the gas tank of course). Then with taxes and miscellaneous charges you break into four figures. Hope your problem doesn't turn out as serious but my truck had less than 100,000 miles on it when this happened so fuel pumps, I guess, aren't a 200,000 mile part.

Pappy Goodwill

I really don't think it's a fuel pump thing. It may sit all weekend (Friday 4:30 pm to Monday 7:00 am) and fire right up first try Monday morning. It sits for 2 minutes while I run in the convenience store for a cup of coffee and: nada. I've gone for a week or two without any trouble, then every other time it won't start. This morning it would't start, I got P.O.'d and shoved inward on the key and it started. All day long, inward pressure on the ignition switch and it started. It may just be on a cooperative binge and I may be just dreaming that it's the ignition switch.

BareBonesXL

When you say won't "start" do you mean the engine won't even turn over/spin/crank? Or that it turns over but doesn't fire? Why would you even think to press inward on the switch unless it wasn't turning over?

Not really clear what you're describing, that's why I tried to summarize it earlier.

Jbrew

Anyone mention the inertia reset ? I didn't see it, might be worth a look....before going after pump integrity anyway.