I just recently bought a 89 302 AOD with 160,000 on it. I like to run OEM parts on my cars but when I priced the dist. cap and rotor from the dealership I almost *****...$39.50 for just the cap. I have been doing some searching on here and it seems that a lot of people are using MSD cap and rotor as well as the coil. I was planning on using the 9MM Ford wires but am looking for cap, rotor, and coil and whatever else I may need for a good tune up since I do not know the last time it had one.

I know my truck is EEC-IV but what about TFI? What does TFI stand for? Just want to make sure I order the correct parts/ part #'s or if you guys can point me in the direction of a reputable distributor . Any help would be great!

 

Super-Dav,

When it comes to ignition components the best advice I can think of is the time-honored "you get what you pay for". In other words you don't necessarily need to go to a dealer to get the same quality parts you can get at the aftermarket parts store chain. Don't pay $40.00 for a distributor cap because we all know thats highway robbery but there's no need to go the other direction completely and buy a $9.00 cap in the "automotive" aisle at the local "discount store". Do just what you are doing and research before you buy. I have always replaced ignition components with Ford's own parts so when I belly up to the parts counter at NAPA or Carquest I go for the Motorcraft brand whenever I can.

TFI is an acronym for Thick Film Integrated circuit board. Also referred to as the ignition module, your truck will have it mounted to the side of the distributor casting below the cap. They are available from any parts supplier but again (and this is especially true of electronic components) go for the Motorcraft version if at all possible. It interprets signal from the EEC-IV computer and makes spark timing adjustments and keeps the truck running with a back up pre-programmed timing signal in the event that signal from the computer suddenly stops while you are cruising down the interstate. (Well it should... if it overtemps or loses power in the form of an electrical short or break in the circuit the truck will still die). The module is a hermetically sealed circuit board with a seven-pin connector at one end. It generates a fair amount of heat on its own while in operation so it not only is mounted via two bolts to the distributor casting but it also requires a coating along the metal backing where it contacts the distributor of heat-conductive "goo" that helps the heat it generates drain away from it so that it does not overtemp and fail. This Thick Film of heat transfer compound is where the name stems from. The TFI module is not a routine tune-up replacement item... its too freakin' expensive anyway. It is engine/vehicle specific but not neceassary to replace during a tune-up. If it fails you will know right away, just trust me on this one.

(Not that it matters or you would care but later models had the module relocated to a large heat sink on the driver's inner fender because it was determined that being in such close proximity to the engine the module still had susceptability to heat-related failures).

 

Greystreak- YOU DA MAN! I think I will start calling you Professor Greystreak! LOL

I wasn't going to replace the TFI module, but I just like to be on the same page when I read others posts and look up parts. Some manufacturers list parts for the TFI and other's don't mention it so I just want to make sure I get the correct parts. It has been a few years since I wrenched on one of these trucks, since I sold my 88, so I am just getting back in the swing of things trying to get my new truck into working condition, fixing all the little things that commonly go bad like window motor gears, temp. and fuel sending units and other stuff like that. So thanks again for your replies and help.