Considering swapping an engine from a 1999 3.0 with an automatic transmission and 4wd into the body of a 1991 3.0 manual with 2wd. I would have to take the 1999 engine harness and computer along with the engine. Are there any issues I'm overlooking with taking the engine, harness, and computer from an automatic and running a manual with it? or taking the engine, harness, and computer from a 4wd and running a 2wd with it?

 

No, you would just need to swap over the 1991 3.0l upper and lower intake manifolds over to the 1999 3.0l, and swap in 1991 distributor to replace Cam synchro on the 1999

Assuming engine swap only, if you want to change 1991 to automatic then yes you would need computer and wiring harness from the 1999, and rear drive shaft, you can leave transfer case attached just locked in 2WD

 

Thanks for the reply. What you described does sound like a nice easy approach. Just out of curiosity, is what I described possible? Like, let's say I hated distributors and wanted to use the sensor approach on the 1999, could I use the engine as is from the 1999 and just bring along the computer and harness from the 1999?

 

No, not easily

The 1991 uses a 60-wire EEC-IV OBD1 computer
1999 Uses 104-wire EEC-V OBD2 computer, also its for an automatic trans, so wouldn't work well without an automatic trans hooked up to it

Anything can be done, but extra wiring to get it to work would be needed, and you would need a 1999 manual trans 3.0l computer, 2wd or 4wd don't matter

 

Thanks. Appreciate the knowledge.
Here's another question for you. Are the various ford ranger engines of different sizes fairly interchangeable as far as bolting in to that 1991 3.0 body that I referenced above (with similar modifications like you mentioned)? ie would the Ford Cologne V6 4.0L bolt in as well?

 

No, Ranger engine sizes didn't used the same transmission bolt pattern, so you need the transmission for that size engine along with engine mounts, exhaust, radiator plus computer and wiring for that engine and transmission

You would only do a V8 swap in a Ranger if you wanted to change sizes, because you can't buy a factory V8 Ranger, and same work as any engine size change swap

Plus you can just buy a 4.0l Ranger and for less money than say a 3.0l to 4.0l swap would cost, economically it just doesn't makes sense or Cents, lol

 

What sort of extra wiring comes to mind when you think about doing this (putting a 1999 engine harness and computer into a 1991 body)? I've been running through this in my mind but Im sure I'm overlooking things and I'm curious what you are thinking of.

 

Assuming the 1999 3.0l engine is swapped as well
You need an extra O2 sensor after the Cat converter
You need to change the fuel pump assembly
EVAP system swap <<< optional depending on your Emissions testing, but CEL(check engine light) would be on all the time if you don't

Transmission swap as well if automatic, but if you have to do this the speed sensor becomes an issue
If 1991 manual trans then you would need to add/splice wire to 1999 computer for speed signal

Can't think of anything else, but that might just be lack of imagination on my part, lol

 

thanks! What is the deal with changing the fuel pump assembly? Why is that required? Does 1999 require different PSI?

 

Yes, up to 1997 Rangers used a Return system with 2 fuel lines and a pressure regulator on the engine, running 35psi
1998 and up used Returnless with 1 fuel line and pressure regulator on the gas tank assembly, running 55psi

 

I think the 99 would have PATS

 

+1 ^^^

That would be another system you would have to move over to use the 1999 V6 computer in a 1991

 

Ah, that would explain where the other line is haha. I've been working on removing the 1999 engine and I remember noticing only one line and thinking the return line must be hidden behind something...

 

Are computers and engine harnesses the same if they are using the same EEC? For example, lets say I came across a 1998 manual transmission EEC for a 3.0. It wouldn't have the PATS (they started in 1999, right?). Could I just plug it into my 1999 harness? Or were there differences between the years even when they both were using EEC-V?

 

I'm going to guess NO,
If just switching the EEC worked, that would by-pass the PATS, people would just install a 98 EEC into a 99 or newer to steal the truck.

 

Yes, it will work, but 1998 3.0l only swap for a 1999/2000 3.0l

You will need to ground the Starter Relay in the engine fuse box, not hard to do

The 1999/2000 used PATS type C, it used a separate PATS module above the glove box, it grounded the starter relay if Key "passed the test" and would then send an "OK to start" message to the computer
1998 computer doesn't need the "OK to start"

But there is a problem, the 1998 computer needs a 3 wire Cam position sensor, the 1999 and up 3.0l uses a 2 wire, different signals, not just wires
So you would need to change the cam sensor/synchro unit to 1998 model and get cam sensor connector and wires from a 1995-1998 3.0l in wrecking yard

There are computer turners that can delete PATS and delete automatic trans software as well if you want to use a manual trans

 

Sure seems like a lot of work to get away from a distributor.