4cyl ecu in my 87 bronco ii

[svtcards]

Like title states I have a 2.3 ecu running my 2.9 in my bronco ii. I purchased this bronco last September. It was under 100k miles.interior looked pretty clean.but i really didn't know how much of a mess it was really in until I got and home and started messing with it. As I started continuing the battle trying to fix all the water leaks this thing has . Which been a chore to say the least. I noticed 1 of the leaks was getting pretty close to the ecu in the broken kick panel.so I decided to remove it since i wasn't planning on driving it for a while as I worked on it. As I pulled it out I saw some writing on it.it said 1987 Ford ranger 2wd 2.3l.. now my question is if this truly is a 4cyl ecu is only 4 injectors being controlled on my 2.9l which has 6 injectors in it? It seems to run ok but starts up a tad rough at times. And it doesn't seem to idle up from cold starts and stalls. Im just wondering if it's because of the ecu that's in it causing this. Let me know.

 

[franklin2]

The sure way to verify what you have is to pull the codes. Ford must have known this would be a problem, because one of the first things the ECU does when in diagnostic mode is to spit out how many cylinders the ECU is made for. It will give you half the flashes of the cylinder count, 2 for a 4 cyl, 3 for a 6 cyl, and 4 for a 8 cyl.

 

[rusty ol ranger]

Im not sure a 2.3 ecm would even run a 2.9

 

[svtcards]

Im not sure a 2.3 ecm would even run a 2.9

That's what I thought. I looked up OEM # on it, it does say for a ranger but doesn't say 4cyl or V6. Will do more research. Who ever wrote what engine it controls must of wrote wrong engine size on accident I'm assuming.

 

[Shran]

If the 4 cylinder is bank fired as I imagine it is, the 4 cylinder ECM should run a V6 or even a V8 as long as the number of injector banks matches. Same concept as running a 302 on a 2.9 harness, not ideal as it is not tuned for the extra displacement but it can be done.

 

[scotts90ranger]

Yeah, they ran the same style distributor pickups just with less vanes and were both batch fire (just pairs of 2 instead of 3, only 2 injector outputs in the computer). Sure it's not going to be right but would run...

That could explain some things for sure if it is a 2.3L ecm...

 

[rusty ol ranger]

That's what I thought. I looked up OEM # on it, it does say for a ranger but doesn't say 4cyl or V6. Will do more research. Who ever wrote what engine it controls must of wrote wrong engine size on accident I'm assuming.

You might be able to look up a replacement 4 cylinder ECM and match up the numbers.

 

[SenorNoob]

Lots of things will "run". It's just a matter of how well...

 

[Cees Klumper]

If I were you I would look for a good used ECU that's correct for your truck. You may need one at some point in the future anyway, there's capacitors in there that can go bad for example. Typical price is around $100 and that way you can eliminate possible issues stemming from a non-correct ECU as you may now have. And having a good spare is not a bad idea in any event, I think.
(Like on my more modern daily driver Volvo, the coils have a tendency to go out and rather than replacing all 6 at once, I get by with just replacing them as one goes every couple of years, and I always carry two spares ($40 a piece). My code reader tells me which one is bad and 10 minutes later I am good to go for another couple of years.)