Hello Im thinking about purchasing a used '86 F-150 FI Im assuming its a 5L 302 cuz its fuel injected, but anyway the owner says there are two problems with it one is it needs new injectors, and two it needs new rear main seals, I have some experience with fuel injection so... but my question is, is this TBI? or MFI? Also the rear main seal what do I have to do to replace them...? Whats involved any special tools? and most importantly where the hell is the rear main seal , I personally am a chevy man but Id like to try out a ford, so thats why Ive never heard of a rear main seal, anyway any help or suggestions would be useful Thanks!

 

the injection is what "chevy" called "multi-point" FI( 1 injector per cylinder.) I would be very suspicious of an engine that needs "all" of its injectors replaced. Sounds like the engine is very tired and the seller is using the injectors as the reason for it runing poorly. The rear main seal is just that. The main oil seal on the rear of the engine. It is the oil seal for the crank shaft where it meets the flywheel. Agian, sounds like the engine needs major overhaul. To replace the rear main, you need to remove the trans. and flywheel, drop the oil pan and then you can access the seal. I would negotiate a great price and plan on an engine rebuild.Good Luck

 

An 1986 with these problems is (with great bodywork, paint etc) worth about $500. And if running great worth about $1500. Personally I would pass.

 

well see thats the thing the guy is only askin 500 for it I may offer him 100 if its not running, but anyway Im just lookin for somethin I can tinker with in my spare time...Hopefully the removing the tranny will be a job I can take on by myself =) Anyway thanks for the replys guys

 

ok guys bought the truck, now I have a question, I bought a Repair manual for it, it says its possible to flash trouble codes but it doesnt say how... Could anyone tell me how? or where the Datalink Connector is...

 

the data link is just aft of the air box on the drivers side you will need a $20 code reader from walmart.

Before replacin g the injectors I'd get them cleaned or at least
run your truck to 1/8 tank and throw in a bottle of fuel inject. cleaner.
For the main seal if it's not leaking to bad ; try the new highmileage oil it has seal conditioners in it and may stop the leak in a few hundred miles.
after the regular tune up (plugs wires cap,filters and vacuum leak check)If the engine is still running rough the EGR valve and port often get blocked with soot,also check the pvc valve and clean the O2 sensers.

 

Ok, well @ the moment injectors seem to be "ok", I put a new battery in it, but the alternator isnt putting out any voltage, so could it be that if the lower the voltage the more gas the injectors throw? Anyway Im working on the charging system problem, but I have a few other issues, first is the Speedometer, it isnt working so I think either the cable is broke or somethin wrong with trannie, is there anyway to check? before I replace the cable...? Also the fuel guage isn't working, how would I test this..? Aso where is the sending unit... Another thing there are two tanks, front and back, with a switch on the dashboard, the previous owner said that when he switched to the rear tank he thought the gunk in it fouled the injectors... he hardly used it, Anyway is there a sending unit in the secondary rear tank? Also he said the switcher is bad where it switches from tank to tank, does anyone know where to get a wiring diagram for the tanks and such...? my book doesnt show anything about the second tank or switcher... Thanks guys This is my first ford and I must say its pretty good.

 

If you have to replace the Injectors I would suggest getting a used set from a local mustang shop. I did this with an 86 Tbird that had two injectors that were shot, I took it to my local mustang shop and they had ample supply of 19# injectors for real cheap cause alot of their clients come in with brand new mustangs and put superchargers on em which require larger injectors making the 19# stock ones useless to the mustang owner so they give em to the shop.

My 86 tbird had i think 16-18# injectors it was somthing smaller than the 19# ones I replaced em with but then again 86 was the first year for alot of the ford cars and trucks to go Fuel injection so it could have been some trial and error on Fords part as to what size they were putting in the 5L V8.

Good luck with your truck! I think once you get that joker running good you will convert totally to the Blue Oval, It seems to have that affect! Was an F150 that converted me from the Dark Side!

-Adam

 

I just got my 83 with perfect bodywork and engine rebuilt...paid 4k

 

speedo disconnect it at the tranny and spin it with a drill.

fuel tank senders are on top of tanks in fuel pumps.
I think the sending unit signals go through the tank select sw.

and get the Hanes repair manual 1980-96 it has good wiring diagrams and step by step touble shooting for electronics

 

ok Thanks guys, 4,000 for an 83? wow my body is fine and I only paid $300, I tested all the injectors, back two are a little weak on the spray pattern... Ill replace those two... As for replacing em all, there are no sport shops around here... Also I still can't find the ECM connector, I looked all over the firewall, behind the air filter and nothing... I really need to pull the codes... and also the oil is thin, like theres gas in it... what could it be... my alternator was completely dead, got a new one on the way. Another thing is when starting it, it starts fine when its been sitting for a while, but last night I tried to start after it had been run for like 5 min, it wouldn't start... smelled like fuel too.... also the idle is really erradic, don't know what its @ yet, putting my tach on tomorrow. One more thing is when revving when you let off the gas, it doesn't go down right away, it takes a few seconds for the rpms to drop... not sure what all this means but... also the battery has been disconnected for like 3 yrs, does the computer need time to "relearn" everything? is there any learn procedure? Thanks you guys are lifesavers.

 

O one more thing, do you guys think I should soak the tips of the injectors in injector cleaner? Also 4 out of the 8 plastic tips on the injectors are cracked, There all on the same side too... What do ya guys think?