OBD 2 4.0 into an 86 bronco 2

[cp2295]

So I was thinking about swapping a 4.0 into the bronco, my 2.9 is tired and burning oil and doesn’t run quite right. I personally like obd2 much better than obd1. I also like MAF sensors vs MAP sensors. If I were to get a complete engine harness, and possibly a body harness from a ranger how difficult might it be? I’m pretty good at wiring, have rewired a couple of harnesses. I figure the ecu only needs so many powers and grounds to function properly so if I read the diagram and figured that out I should be okay. Then run the obd2 port up under the dash. Wouldn’t be too concerned about engine codes as I don’t have to pass emmisions in this old truck. Only engine codes I could think of getting anyways are a post cat o2 sensor (since I wouldn’t run one) and maybe a speedo sensor code since I’d just use the Broncos cable driven speedo. Also, would my stock gauges work or are the values different for the 4.0s sensors...? Might even be able to put the 2.9s dash sensors onto the 4.0 engine. Another issue I can think of is fuel pressure, would i need to swap an in tank fuel pump into the bronco or would I be okay if I got a 4.0 with a return type fuel system? And just used system that’s in the rig now.

The 4.0 should just bolt into place am I wrong? Probably going to swap an m5r1 for the fm145 that is on its way out anyways too.

Anything else anyone can think of let me know appreciate it thanks.

 

[adsm08]

Wow. So many questions that have been asked and answered 100 or more times around here.

The 4.0 system, even the OBD2 system, is not hard to make stand-alone, as you guessed. The earlier you go the better though, as in later years you start having to deal with things like PATS and the IC becoming it's own module.

As far as dash indicators the temp gauge is the oil pressure is the only one that is an issue. In 89 the switch reversed polarity, so using an 89+ engine against an 88 or earlier dash oil pressure turns the light on or makes the gauge go to 0. Simple matter of just swapping the earlier switch, or putting a mechanical gauge in.

Fuel system will be fine. Connections at the rail will have to be altered to make the connection. The 2.9 fuel rail is one side male, the other female, the 4.0 is two of the same kind, and I think one of the sizes is different. On my Ranger I shortened the lines to the rail and added the correct barrels. On my B2 I used a section of old line I had to make "jumpers" that go between the engine and the body fuel lines.

There was a build thread here a few years ago were someone fitted an 04 dash into an 87 cab after the engine in his 87 blew and his 04 got rear-ended. Took the whole interior, engine, trans, anything good and useable off the 04 and put it to the 87.