Thanks very much for the information. This is great news since I can get the 1990 F250 (donor truck) for free.

 

I finally got the 1990 engine in my 1995 F150. I used the distributor and upper plenum off the 1995 engine. Started and ran great for 2 minutes.....then it died and won't start. Has spark. Smells gassy. What causes these computer controlled rigs to flood out?

 

Is your '95 truck mass air?
Did you use any wiring from the '90?

Concerning point #1 above.. if your truck is mass air you have a big problem, the '90 motor has the old 302 firing order while '95 truck is setup for the HO firing order so both the plugs and injectors are out of sync with the motor. That's a big problem because fixing it involves either reqiring the injectors or swapping the cam.

Concerning point #2.. you cannot use any wiring from the old truck.. it's simply not compatable with everything in the '95... mass air or not.

 

Yes, I believe my 1995 truck is a Mass Air truck. I thought the 1990 truck was mass air as well.......maybe I don't know what I am looking at.

I did not use any of the 1990 wiring. I did use the 1990 injectors. I only swapped the upper intake. I don't know if this is helpful to mention, but the 2 upper intakes were very similar....it was just easier to keep the 1995 upper for everything to hook up right.

I have an extra wire coming out from under the front of the upper plenum. I can't figure out where it plugs in. I am pretty sure it is not extra....since it is clean and not full of grease.

Thanks for the help.

 

Yeah the upper intakes are the same so you didn't save anything work there and that extra wire could be a problem but that's the least of your concerns... you have a major mismatch between the engine's firing order and the '95 EFI system so this motor will never run right unless 4 injectors wires are swapped around or you change the cam. The injector wires that have to be swapped are 3 to 5 and 7 to 4 and to do this you either have to take the injectors harness apart and physically move the wires or move the associated pins in the EEC connector or where the engine harness connects to the chassis harness.

 

I guess I'll be changing some wiring around.....easier than swapping the cam. Does it make any sense that the engine seemed to run fine for a couple minutes? Maybe since there was no load, the mismatch was unnoticeable. Thanks again. I'll post an update......hopefully without more questions.

 

Another question. Not questioning your knowledge....you know way more about this than I do......just trying to understand. How come when I look up the firing order for a 1990 F250 5.0 engine (donor) and compare it to the firing order for a 1995 F150 5.0 engine, they are the same? Is it possible that the 1990 has the same injection system as the 1995?

Thanks!!!!

 

Where are you looking up this info? There is all kinds of wrong info out there on the web.. it keeps us regulars pretty busy here.

There is zero chance that these two motors have the same firing order if indeed it came out of a 1990 truck, the only way it would be the same is if it came out of a Mustang.

 

Yeah, I know there is a lot of bad info out there. That's why I wanted to run it past you. The website was called autorepair.about.com. You can look up firing orders by year, make, and model....not very useful when their info is incorrect. My donor engine definitely came out of a 1990 F250.....I have the whole truck. When did the firing order change in the trucks?

Since I swapped distributors, maybe I got the spark plug firing order correct, but the injector firing order is wrong. Could this explain why the engine seemed to run well....that is, until it stopped running altogether? Possibly the misfiring injectors led to unburned fuel, causing the fuel smell.

Hopefully I'll have good news in the next few days.

 

I would say if you got a 5.0L out of a 1990 F250 truck you found a very rare truck.
Most F250 had the 4.9L or 5.8L or 7.5L or 7.3L engines.

If the engine you have is a 5.8L then yes it would have the same firing order as the 1995 5.0L engine.

Check the VIN on the door of the 1990 truck to see what engine it had in it.

 

I worked on the truck more this afternoon. My donor truck.....the 1990 F250 is definitely a 5.0 (VIN N).......I agree, an unlikely engine to find in an F250. Of course you were right about everything. The 95 has a different firing order. It runs, but you can tell it is not firing in the right order. I am not looking forward to taking the injector wiring apart, but it beats swapping the cam. I found where my extra wire goes.

Another question.....the 1995 had an electrical 3 prong plug on a freeze plug (passenger side rear of engine). What is that for? Is it necessary, or just a block heater?

Thanks!

 

That's the block heater.

 

No not at all I have seen plenty of these... it's usually the LD F250.

 

It has been a long time coming, but my 90 to 95 engine swap is finally complete. My truck is back on the road and runs great! A friend of mine rewired the injectors to match the 1990 firing order. So far, no check engine lights and no problems. Thanks to all those who provided answers to my questions.

Highway 101

 

Thanks for the followup and good to hear you got it running correctly. In the past we have had Ford Racing tech support guys say it isn't necessary that the injector firing order match the engine firing order in a sequential injection vehicle. It's good to have proof(outside my own experience) that this info is totally wrong.