Mama always said, the only stupid Question is the one not asked.
I have an 87 F-150 2wd. 5.0 EFI 32,000m on ODO, duals after converter. One strong old truck for a 302! Sounds awsome for no headers.

It was a badly neglected vehicle when I bought it a month ago. Had to do all the usual stuff, some still needing done. Added some tunes ( radio would come and go on bumps), did tranny swap from a wreck, (had shift probs we couldn’t rectify) unclogged a severe radiator full of MUD, (Could barely force water thru it with drain **** removed) flushed engine and radiator (still need to do heater core cause it don’t heat up too good.), replaced thermostat, repaired torn heater hose, replaced horn, (hot wired but no honk) and the lighter had a loose screw laying in it, and when punching the lighter in, the lighter/horn/cruise fuse blew. Repaired PS leaks x3, replaced smog pump (thought at first I had an engine knock WHEW!) replaced Fuel pump and sender in front tank (rear still don’t read and that pump acts as if its going downhill too). It appears to have been a farm truck. It has absolutely no (ZERO) oil leaks whatsoever from any location on the Engine. (Very ODD!!) Truck Runs Great. Even looks real nice aside from some clear coat that has peeled on top of hood and it even has a descent interior. However, when I was doing the transmission swap, (which I knew was bad when I bought her), I immediately noticed that there was no harness connection at the O2 sensor on the exhaust just in front of the converter. Didn’t give it a lot of thought at the time with that big C-6 in my hands and I knew the truck ran well. (main reason purchased) Started looking around later, found that 2 harness wires had been lodged between the frame and cross member on that side of the vehicle, and they appeared to have had the connector torn off them. They were not in a jacket. Was this and accident resulting from a trip through some brush, or did someone do this intentionally? I traced these wires back at a later time, and they travel thru the harness across the back of the engine block and into a larger harness over the break booster and probably into the computer inside the cab. I have stored them away until I am certain as to their purpose. (as if I don’t already know) There were several wires in the engine compartment that I found to be quite brittle, some were missing insulation on the connector ends, some were not in jackets etc, and there were some that had been taped up in some shoddy repair attempt that I had to tend to. Obviously someone had jacked with the wiring at some point a little, as I know is often the case on old second hand vehicles. Most of these problem areas were around the fuel injectors, and across the top of the engine drivers side. I have an emissions light on the dash panel at bottom left side of steering wheel. It seems to work as it’s supposed to. Comes on w/key, goes off when vehicle starts. Gauges all operate properly, albeit the Oil Pressure tends to bounce erratically and read negative at idle. Old girls a little testy on real cold mornings as to how it idles, for about 5 minutes (it is in severe need of new plug wires still, old boots are melted and decayed on bottom nearest exhaust manifolds) other than that it runs absolutely great. Barely ever a miss! How can this be with no O2 sensor for the computer? If these 2 wires that were lodged in the frame rails, are supposed to be connected to the O2 sensor, I am missing a connector, and am left wondering why would someone have not made some of these repairs and kept this vehicle. Am I missing a bigger picture here? Was there simply a bad sensor, and some dits just didn’t have enough gumption to fix it ( as was the case with many small things on the truck)? Is there a bomb about to go off in my truck? It Runs sooooo good tho????? I have a ford Code scanner and as soon as it is back to normal weather conditions in west Texas, I will see if I get any codes. In the interim, I thought Id pick some brains. Some of you dudes are pretty ford quick!@ For future reference, whats the possibilities of running the EFI on a duraspark 2?

 

it seems to me that only with only 32 k you should not have any of these problems and if you do then the truck was seriously abused. as for the O2 sensor I just bought one yesterday and auto zone offers a generic version that you have to wire yourself, or the harness version ( i chose the harness). that could be one reason that there is no harness. hope this helps.

Chris

 

The computer really uses the O2 sensor as feedback to see if its fuel mixture is correct. If the computer is dead on with its estimation of the proper fuel ratio, then it will run just fine. However, if some operating parameters change, the computer will not know what the actual air/fuel ratio is. You can either wire an O2 sensor directly to the wires, or find a harness to go from the passenger side fender connection down to the O2 sensor, so all you will have to do is plug in. There should be 3 wires there, one is 12V with the key on, one is a ground, and one is a signal to the computer. Are you sure the truck doesn't have 132000 miles? You won't be able to run Duraspark II with EFI, since Duraspark uses a different distributor and ignition controls than EFI. If you remove the EFI distributor, the computer will not be able to run the fuel injection or ignition.