I just purchase a 86 f150 short bed XLT Lariat that HAD an EFI 302. Previous owner put in a EFI 302 out of a 94 f150 extended cab….. the problem, he mounted the block but never completed the installation. He claims he never found anyone to do the wiring. I have both the 86 and 94 wiring/computer.

Questions:
1. is this engine swap doable?
2. If so, should I use 86 or 94 wiring/computer?
3. if not, what year 302 engines should I look for?

 

The guy had no idea what he was doing.

1) Yes
2) You need to use the ‘86 wiring and computer. None of the ‘94 electrical will work without wiring modifications.
3) A 302 block is a 302 block. The difference is that the ‘94 should have a roller camshaft. Use the accessories and brackets from the truck because the ‘94 used a different a/c compressor and R-134a refrigerant. The serpentine belt system is also different.

 

Welcome to FTE

So you have a good motor sitting in the engine bay and you need to wire it if I get it right.
First I am not up on the EFI trucks other then what I have seen here but ....

Do you need to pass smog and if so do they look at the motor and what all is installed?
What parts do you have from the 86 EFI system and the 94 EFI system?
Also if you have said parts for either system how will you know if they are good or not?
My thinking is if the 86 truck was EFI it might be best to go back with that but thhen again the factory system I dont think was all that great and trying to get it back together a PITA.
If you dont have all the parts for either EFI system and dont have smog maybe an intake swap and carb is the way to go?
BTW what transmission dose the truck have?
Dave ----

 

Put all the 1986 EFI back on it. It will all plug back into the truck. There is a chance that some of the 94 sensors are different as you start plugging in the 86 wiring. If you have access to the 86 block/sensors, grab what you need and transfer it over to the 94 block. If you do not have the old engine anymore, then you will have to buy some pieces, but there will most likely not be very many you need to buy.

Then you will have a 86 truck, with 86 EFI and wiring. You can go to any Ford manual and everything will match up to the factory wiring diagrams.

 

I'd think the 86 option would be best, too.

To help determine which sensors are the same for 86 and 94, RockAuto is a great resource. Open two windows, one for each year. Then it's easy to see which parts are effective for both years.

 

The sensors are the same if both engines were speed density. The ‘94 could be mass air if it had an automatic transmission. Then the air temp sensor would have been in the air box instead of in the intake manifold. Using the lower intake manifold from the ‘86 solves that problem.

 

First of all, all the above posts are good advice.

I just wanted to add that if you use the 86 302 V belt pulley system, you need to change the timing covers and water pump. Serpentine belt used a reverse water pump.

If it was my truck, I'd keep the serpentine belt.

 

The above is true, but not always. Some of these trucks did have a serpentine belt, but the waterpump turned the normal way. You can tell this by looking at the pulley. If the waterpump pulley has ribs, it turns the conventional way. If the waterpump pulley is smooth, that means it runs on the backside of the belt and it does turn backwards. You do not think Ford would make it too easy do you?

 

The 94 and 86 distributor wiring is different. The early one has the TFI module on it and the later is remote mount. Either one will physically drop into either block, but it will need to match your harness

 

The easy button is the ‘86 distributor with the ‘94 gear.

 

[QUOTE=My4Fordtrucks;21098467]The guy had no idea what he was doing.

1) Yes
2) You need to use the ‘86 wiring and computer. None of the ‘94 electrical will work without wiring modifications.
3) A 302 block is a 302 block. The difference is that the ‘94 should have a roller camshaft. Use the accessories and brackets from the truck because the ‘94 used a different a/c compressor and R-134a refrigerant. The serpentine belt system is also different.[/

This caught my interest I have a 1986 F150 got the engine as a basket case it's a 91 block roller lifter and it has the serpentine Hardware all new including the water pump and I think it's a neat idea to run Serpentine and roll arised cam and lifters since the old block I never got with the truck I like the idea of the later model Hardware for Simplicity and more economical with roller raised valve train with 86 EFI Hardware which was original with the truck because it had a 302 5.0 and the state that I live in has no eCheck for that age truck.

 

If it is a truck engine it still has a flat tappet cam unless someone changed it to a roller. More economical?

 

All I know is 302 1991 roller cam and more economical because better fuel mpg and no oil additives to protect flat tapped cam

 

Picked up the truck this weekend.

Turn out the previous owner bought the 86 truck with no engine/transmission. He then bought a working 94 extended cab and transfer everything he could to the 86…. Engine, transmission, differential, gas tanks, etc. He transfer the entire engine bay wiring from the 94 to the 86. The wiring he left un touch is the wiring behind the firewall(everything under the dashboard). Even the headlights are unplugs cause the connector are different 😡 IT’S A TOTAL MESS. I have some of the 86 engine bay wiring but I don’t think it complete.

What do you all recommend I do? How should I tackle this mess?

 

Oh my, that will be a mess!

If he left the original 86 wiring in place, you may be ok. It gets a bit detailed, but the 86 had two extensions through the firewall , one on each side up to respective headlights. No firewall plugs on this bit of harness. The EFI harness was something of an add on. It passed through the firewall behind the engine and the ECM is mounted under the dash, just to the right of the driver's footwell. If it's still there, you may be able to wire up the 94 engine to the 86 ECM, but you also mention the transmission was swapped. Next question is, which transmission do you have? 4r70W and E4OD will require the 94 ECM as they are electronically shifted. Original transmission in the 86 would have been an AOD or maybe a C6. Of course, if this is a manual transmission you can ignore any ECM connection. 94 wiring is quite different. ECM was mounted through the firewall down by the driver side kick panel. ECM wiring is integrated into the underhood wiring harness and there is a multi pinned disconnect where the cab harness and underhood harness meet at the firewall.

You would do well to obtain good OEM wiring diagrams for both trucks. If you were anywhere close to Saskatchewan Canada, I could help, but that's probably unlikely. Plus, it's nasty cold out here these days.