'89 Bronco II 4.0L Build

[dclack]

Hey everyone; new guy here. Quick intro: I have '02 Excursion 7.3L, '97 F250 7.3L, and a '73 Bronco 5.0L EFI. So I usually spend most of my forum time on FTE or Classic Broncos. But my 15 year old son just picked an '89 Bronco II that came with a 4.0 and 5spd from a 2000 Ranger. The guy had the 4.0 sitting in the Bronco but no wiring has been touched. It came with the 2000 harness and ECU so we are planning to make that setup work. I know that will be more work than getting a pre-95 harness and ECU, but we're up for the challenge. I know a guy that can tune some of the unnecessary items out of the 2000 ECU, so that should help a lot. I'm sure this has been done before, but I haven't found any build threads. Does anyone have a link to one?

We had to go just south of Grants Pass OR to get it; over 8 hours each way. But it was worth it. I have not found any rust and the interior just needs a good cleaning. For $700, I think it was a steal. My son is pretty stoked about it. Hopefully we get it on the road before he turns 16 in June. Here's a couple pics of us getting it.

 

[RobbieD]

Nice looking B2. It should make for a great runner, and good luck on getting the wiring together.

I'm sure you'll be getting some input here on getting those loose ends tied up.

Welcome to TRS.

 

[dclack]

Well, we finally started working on this project; mostly just trying to see what parts we have and what we need. We did get the M5OD and front driveline installed. I have decided to go with the EEC-IV control and not the OBD-II. In looking at the parts needed, I think I need to buy a parts rig. We searched all of the local junkyards and couldn't find any '91-94 Explorers.

 

[RobbieD]

Others with more knowledge may confirm or correct, but a 1990 through 1992 Ranger with a 4.0 should also be a donor option.

 

[SenorNoob]

True.^ In fact Ranger would be better. A 90 Ranger harness might even just plug in to an 89. It would certainly be VERY close.

 

[dclack]

I've been looking for both, but haven't found either in any local junk yards. The hard part in finding a Ranger is that they also came with the 4 cyl (2.3L?) and the 2.9L, whereas all Explorers had the 4.0. I think I found a few options further away; hopefully I'll be able to get something soon.

 

[dclack]

Found a '91 Explorer with a 5spd for $400. This should make things easier.

 

[RobbieD]

A 4-door Explorer with a 5-speed for $400?

I hate you!



Just kidding, of course. Damn good score!

 

[gaz]

@dclack
You have some interesting options, I like using the 91 PCM, harnesses and peripherals. If you go 100% 91 wire harness, PCM with your 00 engine, you are almost done.

The difference is the location of the Explorer's big round wire bundle on the driver's side. If you also chose to use the Explorer dash/instruments and steering column, then the dash and column structural attachments become the ONLY facets to to resolve:
• BII dash attaches with 6 upper points and 5 lower
• Explorer attaches with 4 upper and 5 lower
* These differences are complicated by there locations, though easily corrected. I used the Explorer dash lower support bracket but kept the BII gas pedal. It lines up nicer with the BII's transmission hump

You will have light systems options but I feel that a new stand alone system controlled by the original light switch, controlling the new dedicated relays, powered directly from the battery. You can use 12 or 14 gauge wire which will deliver more current, providing improved lighting, even with the original headlights. Superior lighting potential through this new stand alone harness can be achieved using new, aftermarket housings and improved, inexpensive halogen bulbs ..)

I further suggest scraping that cranksharft driven fan/clutch for a 2,800 cfpm 15"electric fan, remote engine oil filter with cooler.

Welcome from the PNW..)

 

[dclack]

A 4-door Explorer with a 5-speed for $400?

I hate you!



Just kidding, of course. Damn good score!

Yeah, it was such a good deal that I jumped on it as fast as I could. I'm hoping to make my money back selling parts I don't need before sending it to the scrap yard.

@dclack
You have some interesting options, I like using the 91 PCM, harnesses and peripherals. If you go 100% 91 wire harness, PCM with your 00 engine, you are almost done.

The difference is the location of the Explorer's big round wire bundle on the driver's side. If you also chose to use the Explorer dash/instruments and steering column, then the dash and column structural attachments become the ONLY facets to to resolve:
• BII dash attaches with 6 upper points and 5 lower
• Explorer attaches with 4 upper and 5 lower
* These differences are complicated by there locations, though easily corrected. I used the Explorer dash lower support bracket but kept the BII gas pedal. It lines up nicer with the BII's transmission hump

You will have light systems options but I feel that a new stand alone system controlled by the original light switch, controlling the new dedicated relays, powered directly from the battery. You can use 12 or 14 gauge wire which will deliver more current, providing improved lighting, even with the original headlights. Superior lighting potential through this new stand alone harness can be achieved using new, aftermarket housings and improved, inexpensive halogen bulbs ..)

I further suggest scraping that cranksharft driven fan/clutch for a 2,800 cfpm 15"electric fan, remote engine oil filter with cooler.

Welcome from the PNW..)

I think we will just be using the 91 PCM, harnesses, and peripherals. This Explorer has the nasty red interior, so we will not be swapping the dash (B2 interior is blue). Headlight rewiring will probably happen sometime. I've done that for my '73 Bronco because the thermal breaker kept tripping; I need to do it for my '97 F250 as well.

Is there issues with the crank driven fan not pulling enough air for the 4.0?

 

[dclack]

Another question for everyone, the 2000 engine has a plastic upper intake, whereas the '91 has the aluminum intake. Is there any advantage or reason to run one over the other?

 

[gaz]

@dclack
The reason to remove the crankshaft powered fan/clutch is that it presents a constant parasitic load on the engine, whereas an electric fan does add to the electrical load (though hardly ever powered on), it presents no physical parasitic load on the engine...better fuel economy.

I used to wait until the fan/clutch failed to perform the swap; if happen to get ahold of one of these or a friend asks for help, I always recommend the swap for improved performance and fuel economy. The cost is about the same either way and each system lasts about as long as the other; the predominant difference being reduced fuel consumption.

As far as cooling potential, the crankshaft driven fan/clutch is OEM component designed and capable of adequately maintaining normal engine operational temps. Switching to an electric fan, like 99% of the automotive industry did in the 1990's, will reduce the workload that your engine is feeling and free up a little power...not to be confused with adding power, simply reducing the amount of power being lost to constantly spin that weight.

I used to believe that the improvement was so noticable because of the small displacement of the 2.9l and 4.0l, then I did the same thing to my 5.2l magnum V8 powered Dakota...it was an easily noticable difference in both fuel economy and throttle response; simply one of the best improvements for more efficient fuel economy that I've ever learned. I wish that I had done it 6 years sooner on my Ranger. At the time I chose not to because of potential factory warranty issues.

 

[SenorNoob]

I would use the aluminum intake just for durability. Old plastic tends to get brittle and crack. It does have the advantage of not soaking up under hood heat and passing it to the intake air..

 

[sgtsandman]

The only catch with switching from a clutch fan to electric, is making sure the air flow needed is adequate. While the clutch fan does create paracitic drag, for a given size, they tend to create a stronger air flow than electric fan. So do your research before you make the jump.

 

[dclack]

Yeah, I think we will be sticking with the mechanical fan for now. Right now, it's all about getting it running for as cheap as possible. My son spent all his cash to get the Bronco, so all the parts and parts rig are being funded by me.