• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

87 2.9L tank pump won't work when rail pump is plugged in


manley

Member
Joined
Oct 20, 2007
Messages
40
Reaction score
4
Points
8
Location
Richmond, IN
Vehicle Year
1987
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
2.9 swapping to 4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31
My credo
Wut?
Some history:

Bought the truck from a guy who had the truck running, but it puked coolant out of the exhaust. Blown head gasket, so he swapped in another 2.9l and never got it running again. He sent a video of it running with the first engine. I think the truck sat for a long time before he bought it.

So far, I fixed a missing hose in tank between pump and hard fuel line and new EEC relay. Inertia switch tests fine. Fuel pump relay test fine. Both pumps worked when removed and directly wired to 12V.

When the high pressure pump on the rail is unplugged, the tank pump will turn on. When I plug the high pressure pump in, neither will work. I'm thinking pinched wire somewhere.... unless someone else has some knowledge to share with me? Strange, strange problem.
 


adsm08

Senior Master Grease Monkey
Supporting Member
Article Contributor
Ford Technician
TRS 20th Anniversary
Joined
Sep 20, 2009
Messages
34,623
Reaction score
3,613
Points
113
Location
Dillsburg PA
Vehicle Year
1987
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31X10.50X15
Jump 12V from the battery to the plug near the LH side of the engine bay where the fuel pump wires split off. It will be a small plug with a single pink/black wire going in and two of them coming out the other side, somewhere more or less right below the brake booster.

If both pumps run that way suspect a damaged wire between the relay and that plug that is unable to carry enough amperage to run both at the same time.
 

manley

Member
Joined
Oct 20, 2007
Messages
40
Reaction score
4
Points
8
Location
Richmond, IN
Vehicle Year
1987
Make / Model
Ford Ranger
Engine Type
4.0 V6
Engine Size
2.9 swapping to 4.0
Transmission
Manual
2WD / 4WD
4WD
Tire Size
31
My credo
Wut?
Got it! Thanks for the help! Both pumps turned on when I connected the pink and black wire to 12V. Started tracing it back, splice looked good, not damage to be seen. Pulled the inertia switch off and jumped the wires, truck fired right up. Obviously I did something wrong when I was checking the inertia switch. Appreciate the help a lot!
 

Sponsored Ad


Sponsored Ad

Staff online

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Kirby N.
March Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top