90 F150 starting problem

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Jul 16, 2003 | 11:44 AM

ed45306

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Joined: Jul 2003

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From: Ohio

90 F150 starting problem

I need help. I have a '90 F150, EFI 4.9. 5 speed with dual gas tanks and FDM pumps. Sometimes it will run sometimes it wont.
Once it is running I dont have any problem the rest of the day.
When I have the no start/ no run situation, the engine will crank over but not fire. I can hear the fuel pump running. Switch tanks, hear the other pump run.still will not start. When it doesnt start, if I turn the key to on position without cranking the engine, the fuel pump will not shut off after 2-3 seconds. It will keep running.
When it does start I have noticed before turning the key to start that the fuel pump will shut off after 2-3 seconds. Truck runs great after it starts.
Took truck to local garage who had it a week. Sometimes it would start,sometimes it wouldn't.They said no codes showing on computer.Checked fuel pressure and volume, both good. Could not find anything wrong with truck.
I have replaced: fuel pump relay, eec relay, coil, PIP sensor, distributer cap, plugs and wires, ICM, fuel filter.
Any suggestions will be greatly appreciated.

Thanks,
ED

Jul 16, 2003 | 04:34 PM

jimdelta

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Joined: May 2003

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90 F150 starting problem

I HAVE A 93 AREOSTAR THAT WOULD RUN SIMILAR TO YOURS WHEN IT WAS WET OUT OR RAINED HARD THAT DAY. AND IT TURNED OUT TO BE THE ROTOR. YOU SAID YOU CHANGED THE CAP BUT DID YOU CHANGE THE ROTOR ALSO?ALSO BUY QUALITY IGNITION PARTS. I'VE BOUGHT NEW ,CHEAP IGNITION PARTS THAT WERE GARBAGE RIGHT OUT OF THE BOX.

Jul 17, 2003 | 09:26 PM

steve83

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Joined: Nov 2002

Posts: 9,987

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From: Memphis, TN

90 F150 starting problem

The rotor would never cause the pumps to run on. It has to be an intermittent short in the wiring harness, possibly along the frame rail or under the dash near the fuse block.

Jul 20, 2003 | 09:29 PM

fishin4x4

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Joined: Jul 2003

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90 F150 starting problem

I'm having the same problem but have not had quite as many partss replaced as you. I'm not encouraged by your post. The last parts repolaced were cap and rotor - no help. I'll let you know if i gwet it resovled.

Jul 23, 2003 | 01:50 AM

ed45306

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From: Ohio

90 F150 starting problem

fishin4x4, good luck. I replaced the fuel pressure regulator on the fuel rail this past weekend . I still have the same problem. I was told it could be the ignition switch.The switch is around $7.00 at my local autozone. I will pick one up tomorrow. Might not get it in right away but will try Thursday to get it installed. Will let you know if it "fixes" my problem. Not much left to replace

Jul 25, 2003 | 09:46 PM

fishin4x4

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90 F150 starting problem

i replaced the plug wires and when its wam it starts and runs fine, but still won't start in the mornings. I then checked it with a volt meter when it wasn't starting. i got spark to the dist. but not spark to the plug wires. I already replaced cap and rotor, so i'm not sure what is left in the distributor that could be causing the problem. Did your $7 fix work? I could only dream tht $7 will fix mine.

Jul 26, 2003 | 10:28 AM

1yamman350

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Joined: Jul 2003

Posts: 203

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From: Virginia

90 F150 starting problem

i think 7 out of 10 people have this same problem with the EFI 302. if you check for pressur on the fuel raill when it wont start i bet ther is none. everyone says its a short between the rear pump and the booster pump. that pump you here running is probably just the booster pump. if you can find the short you should be just fine. hope you have more luck then me though.