Hi all!

Let me start by saying this truck has been sitting for about 7 years (). Decided since I really miss the truck (was the truck I got when I turned 16) I was going to get her back on the street because I just now have some money I can spend on her. It was running good when I parked it at my grandmothers as a theft deterrent (people think that there is someone else at the house). Life happens and time got away from me as it sat. Truck is a 1987 F-150 4.9 Regular Cab short bed with one gas tank.

Slapped a battery in it and didn't hear the fuel pump so I loaded it up on a trailer and took it so I could work on it. Pulled the bed off and realized it was full of "gas." Later found out that the top of the tank was rusted through and I believe it filled up with rain water over time. Ordered a new tank and fuel pump. Installed both and flushed out the fuel lines up until I got to the o-ring for the reserve on the frame rail. Had to replace it because it was leaking. Followed the lines to the high-pressure fuel pump and replaced it because it wasn't running. Got her running, sort of. She was barely idling and pouring out black smoke. Let her run for a little bit and realized she wasn't going to clear up so I went ahead and replaced all the fuel injectors and spark plugs. Got it back together and she ran a little bit better. Put a fuel pressure gauge on it and checked pressures with key off, on, running, and with the vacuum line off of regulator. All seem to be within spec. I took the computer out and took it apart to find a compaciter leaking so I ordered and whole new unit. No change. I saw a video on YouTube where a guys truck was barely running and it was the EGR so I installed an EGR delete with no change. The next thing I tried was a new MAP sensor with no change. I have noticed that the truck will run 80% better with the MAP unplugged and the vacuum line connected. I'd imagine that the truck reverts to a fail-safe fuel strategy. When the MAP is unplugged, even though it is running better, it will stumble and die a few seconds after you put it in gear.

So, this is where I need you guys/girls suggestions. There is another forum that a guy had an Econoline van with the 4.9 and was having similar issues, but he scrapped the van before he was able to find a fix. This truck doesn't have a check engine light to flash out any codes.

Scrapping is not an option for this truck.

Thank you for any suggestions!
-Matt

 

Has that truck got an O2 sensor on it ?

 

Oh yeah... I haven't checked on that thing yet.

 

Finally got my hands on an OBD1 Ford code reader and pulled the codes. First 3 codes were EGR codes which I expected because the EGR is blocked off. The fourth code is code 87 which is "Fuel pump circuit fault (check inertia switch) – Power / Fuel Pump Circuits." So this is what the truck is doing now. When I turn on the switch I hear the pump prime like it should. When I start the truck it will run with a surging idle or stall a few seconds later. What should I check now? Is it possible the relays are bad? I actually drove it around yesterday. Thanks for the help.

 

Ok since I hate seeing posts with no outcome... Here it is: This post is a reminder to not over took the basics. Pulled the distributor cap off and realized the terminals were corroded. Sanded them down with no change. Bought a set of Motorcraft wires, a new distributor cap, and a new rotor button. Noticed right away that the new rotor button would push the cap up when trying to screw it down. Got everything together... No change. I decided to drive it around the block a few times and she ran better and better, to the point she was back to how she has always ran. I'm guessing a few of the plugs were fouled out and then finally started burning. I still don't know why I was getting the code 87. I'll try to get a video of the old girl today. Now it's time for brakes, rotors, and a muffler.

Moral of the story: "Don't assume stuff is good, even if you think it was relatively new when you parked it."

-Matt