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Is my fuel pump dying and where is it?

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tanman

Is my fuel pump dying and where is it?

86 straight six with Single barrel carb. Truck died on the road. Started after about 10 tries. She’s done that a couple times. I’ve heard it rev a couple times when idling. There have been a couple times when she will bog down when I step on it for a moment.

I tried to listen for the fuel pump to engage when I turn on the ignition. I hade my ear right up to the tank. I don’t hear anything.

All that said I just took my Mom to lunch and had zero issues. Any ideas?

86 F150 4.9 Automatic

Gary Lewis

Re: Is my fuel pump dying and where is it?

Administrator

First, you shouldn't have an electric fuel pump on an '86 w/a 300 six. It should be a mechanical pump on the engine.

Second, I've not had a fuel pump cause that kind of problem. Usually they just quit.

Instead, I think you may have an ignition problem. Perhaps the TFI module, which is notorious for failing?

Let's see what other say, but I think you are losing spark until things cool down.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

grumpin

Re: Is my fuel pump dying and where is it?

I concur, when I first read this I wasn’t sure if the six had a mechanical pump or electric pump.

But the TFI will act like that, and as Gary said, work again when cooled down.

Dane
1986 F250HD SC XLT Lariat 4x4 460 C6-Sold
1992 Bronco XLT 4x4 351W E4OD
1998 GMC Sierra SLE K1500 350 4L60E
Arizona

ratdude747

Re: Is my fuel pump dying and where is it?

In reply to this post by Gary Lewis

As somebody with a similar setup, I agree. Not likely a fuel pump (mechanical if stock, front driver's side of engine block)... more likely a TFI module issue or something else in the ignition. Been burnt on that one before...

1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).

FuzzFace2

Re: Is my fuel pump dying and where is it?

I would say the same, TFI going bad.

It is a little gray box on the side of the dist. with all the wires going into it.
Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

tanman

Re: Is my fuel pump dying and where is it?

I agree. This was happening previously and went away. But it’s returned. Don’t hate me but I bought a HEI dizzy from summit. I will create a post in the projects section documenting the install. I don’t wanna mess with this ignition issue anymore. This is the third and final straw trying to fix it. I don’t have a timing light does anyone know how to swap and keep the timing correct or at least close?

86 F150 4.9 Automatic

ratdude747

Re: Is my fuel pump dying and where is it?

Uhh... are you still running the stock carb (carter YFA feedback) and ECU? If you ditch one part of it, you'll have to ditch all of it, as it only works as a complete system. TFI requires the rest... so unless the last person hacked it, you'll have more than just an ignition system to redo if you want to go the HEI route.

1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).

Gary Lewis

Re: Is my fuel pump dying and where is it?

Administrator

Amen, brother!

My understanding is that the YFA will operate w/o the computer, and obviously the HEI will. But you will have a lot of other wires, sensors, etc that will no longer be operating. And the system won't operate as efficiently.

It might be easier to relocate the TFI module than to change the system so significantly.

Gary, AKA "Gary fellow": Profile

tanman

Re: Is my fuel pump dying and where is it?

I have an intake and header kit coming next week from Clifford. Also a new starter and alternator upgrade. Will the new distributor work at all without swapping out the carb? I was afraid of doing everything at once. So much to troubleshoot.

86 F150 4.9 Automatic

Gary Lewis

Re: Is my fuel pump dying and where is it?

Administrator

Yes, the new distributor will work w/o swapping out the carb. But the computer will have its knickers in a twist and won't control the carb, so the air/fuel ratio won't be spot-on.

You'll need to wire in a relay with at least #12 if not #10 wire from the battery to power the HEI. You can trigger the relay with the wire that currently powers the coil.

Gary, AKA "Gary fellow": Profile

ratdude747

Re: Is my fuel pump dying and where is it?

In reply to this post by Gary Lewis

Should have clarified... by "work", I meant "work well". Air/fuel control will get locked to junk due to the computer likely going into limp mode due to the ignition timing not being ECU controlled.

Will it start? Duh. But it's not a setup I'd suggest driving on for very long.

1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).