86 Ford start problem

[phat rat]

I've got an 86 Ford 1/2 V8 that's giving me problems starting. It was doing ok until last week. I shut it off and went to restart it and it wouldn't start. I thought maybe I'd run it out of gas, gas gauge doesn't work and it's a truck that's only used on the property so it doesn't matter. I put gas in it but it wouldn't start. I was going away the next day and didn't have time to fool with it and I finally got back to it today. It still wouldn't start until I sprayed some carb cleaner into the throttle body. Then it started right up and sat running for at least 5 min. I then drove it about an 1/8 mi. to unload the brush that was on it. Shut it off and it wouldn't start again. Sprayed more carb cleaner into it and it started right back up. If you shut it off and immediately try to restart it won't unless carb cleaner is sprayed in. Any ideas?

[enjenjo]

There is a relay that runs the fuel pump when the key is first turned on for 5 sec. this will produce enough pressure to start. In the past I have found the wires to the relay corroded, keeping the pump from running at key on. The power to run the pump after it starts uses another circuit, so if you can get it started it will run all day. The relay is usually under the hood on the left side.

[phat rat]

Frank, so this a different one than the one with a reset that's inside just just to the right of the trans hump?

[enjenjo]

Frank, so this a different one than the one with a reset that's inside just just to the right of the trans hump?

Yes. that one is the inertial switch.

[phat rat]

Thanks Frank. I'll try it tomorrow and let you know the results.

[wayne petty]

here is the wiring for an 86 F series with a 5.0

http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0900c152/80/07/c0/cd/large/0900c1528007c0cd.gif

the fuel pump relay is top center... so you can verify the wire colors to it..


the EFI main relay powers up the Fuel pump relay.

but it really sounds like the relay is dirty or bad as described above..

i was looking for the colors... usually the efi main relay has a brown connector.. and the fuel pump relay has a green connector...

i posted the diagram above.. so you could verify the wire colors...

i have found fuel pump relays on those ... under the hood... behind the left kick panel.. behind the right kick panel.. behind the glove box...
i just don't remember which..


the stuff online says under the hood..

if you need more info.. i have a ford drivability book stashed away.. probably has the info ... if you need it..

there are a bunch of different relays...  when you find the one with the right color wires...   and you remove it... be sure to google the ford number on it... make sure the replacement is close to being the same...  only minor differences...

the links below are how the various fuel pump relays are wired internally..



RY-46 Relay
   Fuel Inj Pump Relay;FUEL PUMP ; 5 Pin ; Yellow ; Gray ; Black/Green ; OE # E3TB-13A025-A1A;Or {RY-69} ; Use w/{RY-66} Conn.; Years: 1986-1989;


   RY-69 Relay
   Fuel Inj Pump Relay;FUEL PUMP ; 4 pin ; OE Style ; Or {RY-46} ; Use w/{RY-66} Conn.; Years: 1986-1989;
http://images.wrenchead.com/smartpages/partinfo_resize/STA/RY69.jpg

   RY-70 Relay
   Fuel Inj Pump Relay;FUEL PUMP ; Yellow or Gray ; OE # E6VB-13A025-A1A ; Use w/{RY-66} Conn.; Years: 1986-1989;
http://images.wrenchead.com/smartpages/partinfo_resize/STA/RY70.jpg

   RY46  Relay
   Fuel Inj Pump Relay;FUEL PUMP ; 5 Pin ; Yellow ; Gray ; Black/Green ; OE # E3TB-13A025-A1A;Or {RY-69} ; Use w/{RY-66} Conn.; Years: 1986-1989;

[reborn55]

sometimes their is a auxiliary fuel pump om the frame rail right below th toe board.  Check the contacts there--they have a tendency to corrode