87 f 150 no power to fuel pump!

Reply Subscribe

Thread Tools

Search this Thread

May 16, 2019 | 08:02 PM

Pixel123

Thread Starter

New User

Joined: Mar 2019

Posts: 9

Likes: 0

87 f 150 no power to fuel pump!

I have an 87 f 150 4.9 l standard shift that died all of a sudden. When I turn the key the fuel pump doesn’t cut in. I have zero fuel pressure according to gauge. I removed external fuel pump and manually wired it and it operated fine. Fuel pump relay clicks and meter reads 12 v coming from relay. At initial switch I cannot lot read a voltage or at fuel pump connections.still no voltage. Is it my inertia switch gone bad or can I bypass. Thanks any ideas?

May 18, 2019 | 06:53 AM

EPNCSU2006

Lead Driver

Joined: Nov 2002

Posts: 9,557

Likes: 44

From: Concord, NC

Start tracing the wiring from the relay to the tanks. Are you forcing the relay to turn on through the diagnostic test port under hood, or just turning the key? The inertia switch connector had melted partially on my truck many years ago. I don't know if it ever stopped working but it definitely got hot at some point.

May 29, 2019 | 11:38 AM

LxMan1

Moderator

Joined: Dec 2001

Posts: 22,436

Likes: 17

From: Louisville,Ky.

You should have power on at least one side of the inertia switch for a couple of second when you first turn the key on. If not, the problem is upstream.