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-   -   1989 F150 4.9L Fuel issue ???? (https://www.f150online.com/forums/pre-1997-models/292829-1989-f150-4-9l-fuel-issue.html)

Dave13 07-10-2007 02:37 PM

1989 F150 4.9L Fuel issue ????
 
Sputtering and dying. Doesn't matter if it is at idle or hiway speed. Switched tanks, no help. Changed fuel filter, plugs, cap, rotor, wires, no help. Changed in-line fuel pump (external). Worked great for about a week. Then, sputtering and dying and a new one....engine starts racing (about 2200 RPM), then back to sputtering and dying. Any ideas ?
I should mention this truck has 180,000 + miles on it and I am the original owner. I am kind of fond of it. Could it be the fuel pressure regulator ?

Thanks

Dave

Steve83 07-11-2007 03:36 AM

Choppy writing hard to follow - full sentences better.





Have you checked the fuel pressure WHILE it's sputtering? A Sears fuel pressure gauge is just long enough to run out the back of the hood & tuck under a wiper so you can watch it as you drive. Are the in-tank pumps working? Have you ever changed the filter inside the reservoir?

What area do you live in?

Dave13 07-11-2007 10:08 AM

In order to test it while it's sputtering I would have to have a pressure guage, I don't, but I will on Saturday, or sooner, when I buy one. I will also check the filter in the reservoir, I didn't know there was one in there. As for the in-tank pumps I haven't tested them. Do you know of a test procedure for these pumps ?
I live in the Seattle area.
Thanks for the advice, I will be heading to Sears as soon as I can. I will let you know.

Dave

Steve83 07-11-2007 01:21 PM

Don't touch that reservoir until you have a new O-ring that fits it. It'll leak like a sieve if you disturb it. The only way I've found that O-ring is in the box with the filter, but being up North, your truck SHOULD have the external filter instead (not both). Read this recall:

https://www.supermotors.net/getfile/...76fuelline.jpg

Call your local dealer to see if your truck is still eligible for it. If so, it'll be totally free (other than your time & transportation while it's being performed).

To test the pumps, disconnect all but the one you want to check, then put a jumper wire in the DLC as shown at the bottom of this diagram (ignore the top of the diagram - your pumps are VERY different) and turn the key on.

https://www.supermotors.net/getfile/...mbnail/fdm.jpg

You should hear the pump running in the tank. If not, probe its wires to check for power. If it has power, it might just be running quietly. Get a drain pan & pull off the supply line at the reservoir for that pump & see if there's a stream coming out. (It's only ~4psi @ ~3gph, so it won't shoot across the yard.) If you get less than a healthy stream, replace the pump.

If you have no power going to the pump, trace the wiring forward to the fuel tank select switch, the inertia switch, & the FP relay.

That reminds me: you should do this modification ASAP.


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