After replacing my EEC, my farm truck is back running. But after some closer looking I see that the wire running to my h/p fuel pump is wired directly to the fuse panel, slid into a fuse. Does anyone know where the wire from the pump should go. A color guide perhaps. Would like the pump to kick off and on like it should do. Not run all the time when the key is on. I'm thinking this may cause a problem at some point.

 

I have some good wiring diagrams for my 91 I can give you if they apply to yours.

Your truck has low pressure pump in tank and high pressure pump on frame rail? If it does, my diagrams won't help. Only E-series vans used that setup in 1991.

Do you have a single tank or dual tanks?

Funny, I always thought the 90 F-150's had the single in tank high pressure pump. Let me know! Hopefully I can help!

Chris

 

My truck has 2 tanks with a low pressure pump in the tanks and a high pressure pump on the rail. Apparently someone had bypassed the EEC when it went bad and wired the h/p pump directly so it would run. It would have been easier to get a new eec and not done the other stuff. Must have been a money thing. They also changed the ignition switch, which will not allow the key to be removed. And put a starter button in it. Seems like alot of work for something so simple. It is a farm truck now and not driven on the road, but having worked of vehicals for 40 or so years I don't like things scabbed together. There are 3 or 4 wires under the dash that don't go anywhere. I'm not sure if this will cause a problem at some time so would like it fixed. Yes sir she is a real jewel!

 

Wow, learn something every day! I thought they had stopped using the rail mounted H/P Pump in like 1988. Good to know.

Well, hopefully someone with a 90 can chime in here. I'm not sure my diagrams would do any good, so I won't clutter your space with them.

Yeah, thats a lot of work. They must of had a hot date or something to de-engineer it like that.

So the key won't come out of the cylinder? I'd just turn it to RUN, push the little button with a pen and remove the cylinder. New ones aren't expensive. Just stinks you have to rewire all that.

Chris

 

Ya the ignition is just one of many projects on this truck. Luckily it is only a farm truck. Otherwise I would have never bought it, no matter what the price. Hoping the constant running fuel pump won't be a problem as it only runs for short periods. To get me in and out of the fields or gather firewood.

 

Sounds like your truck has been hacked a bit - I hate having to fix stuff like that. Were the original wires not left behind? Maybe tucked away somewhere?

My truck is a '91 and only has the hi-pressure in-tank pump so I can't crawl under mine and be of any assistance.

All that said, since I presume the pump is only running when the ignition is "on", you're really not going to be leaving it running but for a few seconds more than with the stock setup, so no big deal really. Of course, that assumes that both the fuel pump wiring and ignition hacks are safe and reliable of course. And I realize that may be a big assumption.

 

Haven't traced all the wires that are hanging in the wind as of yet. Most gauges don't work, I'm happy the gas gauge works. But very happy to have it running. By all the leaves and debri in the engine compartment I'm guessing it sat for years. It's slow going but it's going. This is the newest vehical I have really tore into, most are 70's era or older.