1987 2.9L to a 1991 4.0L

[Joeschiffman]

I bought an 87 ranger 4x4 with a 2.9 manual and my head gasket went bad the next day. The engine already had some blowby and I had another ranger I could buy cheap (also wanted more power) the 91 ranger I bought for the engine is a 2wd with a 4.0 (also manual) me and a buddy have the new engine in the truck we just haven’t done the wiring or fuel ext. was wondering if anyone had done this swap and could gimme some advice on the wiring or just advice in general. Thanks.

 

[Josh B]

Cool deal Joe. Give it some time, someone will drop some info your way. I don't know a lot about the swap but I think they're fairly similar. Good luck either way

 

[dvdswan]

4.0 Liter Engine Conversion FAQ's - The Ranger Station

Engines & Fuel Systems - The Ranger Station

 

[gaz]

Use the wiring from the 91 in the 87, all of it, every bit, the computer too. It will be simpler to move everything from the 91, all sensors, the entire dash and steering column.

Doing it this way is way more "plug and play". A complete operational system taken form one chassis and placed in a new home.

If you follow this track, the only wiring decisions to make are with the head lights. The better solution there is to build a NEW relay controlled circuit from the battery direct to the headlights (the stock light control switch is still used to energize the relays off/on).

 

[Shran]

While I somewhat agree with gaz on using the donor wiring, be aware that moving the dash & steering column into the donor is not a simple task.

Problem #1 is the firewall requires extensive modifications to make the 2nd gen column fit:

Problem #2 is the pedal assembly supports the dash on 2nd gen trucks but a 2nd gen pedal assembly doesn't fit very well in a 1st gen truck.

Problem #3 is caused by #2, the slave cylinder is at a different length away from the pedals so you have to modify the pushrod to disengage the clutch completely

Problem #4, the 2nd gen dash upper mounts along the windshield are in different spots than a 1st gen and the dash itself is a very tight fit

Problem #5, the big "cannon" plug on the driver's side firewall, this does not exist on a 1st gen so you have to make a new hole for that

Problem #6, minor, you lose your dash speakers

I believe there were a few other ones but as you can imagine it's a lot of work. If I did it again, and I had a 1st gen with a nice interior, I would NOT swap the 2nd gen interior in. I only did because my interior was trashed.

 

[Joeschiffman]

4.0 Liter Engine Conversion FAQ's - The Ranger Station

Engines & Fuel Systems - The Ranger Station

This looks like it’s for a bronco do you know if it’s relatively the same?

 

[dvdswan]

This looks like it’s for a bronco do you know if it’s relatively the same?

As far as I know it for Rangers and Bronco IIs. I can't see installing a 4.0L into a Fullsize truck or Bronco.

 

[Joeschiffman]

Hey so my wiring harness got cut on this (long story lol) and there are identical wires running through it and I’m unsure which ends go to each other. Any help?

 

[Josh B]

Man, wiring is a whole nuther beast. Good luck with it though, wear your thinking cap and bring your patience

 

[SenorNoob]

Post up some detailed pictures of what you have for wiring and maybe some specific questions. It's a difficult thing to explain over the internet...

Very generically, you want the computer and and every wire originally attached to it (all the way out to each sensor) from the 91. I found it easier to pull all of the relays and the underhood fuse box from the donor too. When you pulled the engine, should've just unplugged a large connector to the rear passenger side. It would plug right back into the other wiring you need. If done right the only splices required are at the firewall on the driver's side, to keep the 87 dash.

When everything engine related is removed from the 87, you'll still have a few wires coming from the firewall going out to lights, horn, and fuel pump. Those need to stay original.

I just noticed your in TN. Where abouts? I'm in Lafayette myself. If you're close enough I'd be willing to come help if ya want.

 

[Joeschiffman]

Post up some detailed pictures of what you have for wiring and maybe some specific questions. It's a difficult thing to explain over the internet...

Very generically, you want the computer and and every wire originally attached to it (all the way out to each sensor) from the 91. I found it easier to pull all of the relays and the underhood fuse box from the donor too. When you pulled the engine, should've just unplugged a large connector to the rear passenger side. It would plug right back into the other wiring you need. If done right the only splices required are at the firewall on the driver's side, to keep the 87 dash.

When everything engine related is removed from the 87, you'll still have a few wires coming from the firewall going out to lights, horn, and fuel pump. Those need to stay original.

I just noticed your in TN. Where abouts? I'm in Lafayette myself. If you're close enough I'd be willing to come help if ya want.

The wiring harness has been cut in two different spots the wires run from that fuse box to the plug that goes into the interior. I patched a handful of wires then noticed the identical black and white wires. So I tried to find a wiring diagram for the truck so I could trace them to where they need to go. But couldn’t find anything helpful/: thanks.
I’ve posted on the wanted thread for a new wiring harness. And I’ve contacted a scrap company that might have what I need. I’ll keep y’all posted on this. Thanks for all the help

 

[bobbywalter]

just use the eec harness and pdb.

 

[SenorNoob]

I'd be willing to bet that those go to pins 40 and 60 on the ECU. Which are both ground from the battery.

 

[lil_Blue_Ford]

Id use an OHM meter to probe a wire on the cut end and check the plugs until you find where it goes to. I have an old meter set up with an alligator clip on one lead so I can strip a little insulation off and clip that end on and probe with the other. Pain in the neck, but it works. Label each wire as you trace it. Masking tape works good for temporary labels. If I think I’m ever going to have to trace stuff out again I print labels with a labelmaker.

I’m going to say it… I don’t like the looks of your splices. Not sure what your method is, but it looks like you may be inviting future problems. Be less of a worry in the cab, but IMHO, the best two methods for splicing on a vehicle is solder and glue-lined heat shrink or the solder-shrink connectors that have a ring of solder that melts when it gets hit with a heat gun inside of a bit of heat shrink. Even those are not quite as good as unbroken wire, but much better than wrapping with tape.

 

[Greenasspider]

Hi , currently in the middle of swap . 87 supercab 4x4 . 2.9L ,out , dash out . Firewall stripped inside and out . Front clip removed. Installing , 2006 4.0 L SOHC .
Donor cab , dash firewall is 2003. I see where the brake , clutch pedal assemblies will be an issue for installing the new dash .
The question i have today is . clutch and flywheel for 4.0 L , will this mate up to transmission , bell housing , stock from 2.9L ? The bell housing will bolt to the engine , the splines and pilot on the input shaft are the same, but the distance to release bearing doesn't seem to measure up . Has anyone done this ? Or is there another clutch that will work ? The flywheel thickness is the biggest difference . Can someone please tell me the thickness of the 2.9L flywheel for manual transmission as i no longer have it .