94 Ranger 4.0 engine into a 91 Ranger

[SenorNoob]

By my understanding the newer engines (Or Cali models maybe IDK) used that spot to run a sensor AND drive the oil pump. The sensor tends to break on them. However, the older oil pump drive should fit in that hole. I don't think it really matters which one you use unless you need the sensor for your computer.

Oh, and btw, the newer injectors will work with the older computer. I'm using them now on my build. I do have a very rich running engine though. Might be related, but I think it's cause I have a bad (or the wrong) O2 sensor.

 

[FordRanger1991]

By my understanding the newer engines (Or Cali models maybe IDK) used that spot to run a sensor AND drive the oil pump. The sensor tends to break on them. However, the older oil pump drive should fit in that hole. I don't think it really matters which one you use unless you need the sensor for your computer.

Oh, and btw, the newer injectors will work with the older computer. I'm using them now on my build. I do have a very rich running engine though. Might be related, but I think it's cause I have a bad (or the wrong) O2 sensor.

ya that's what I was thinking. I will probably put the non sensor oil pump drive in the hole from the non cali motor just so I don't have a sensor sticking out that does nothing lol but thanks for the response. I probably will just put in the 92 injectors though just to make sure. Let me know though if that rich running is from the O2 sensor and not the injectors. Would be nice to know if those 94 injectors will work with the older computers for a future swap on the bros truck.

Thanks again Noob!

lol was going to put SeniorNoob but Noob sounded funny haha.

 

[SenorNoob]

It's working correctly. i had the signal and signal ground wires crossed on the O2 sensor... At least as far as I can tell. Fired it up tonight and no more miss.

Edit: The name is supposed to be funny. I use it when gaming.. It does however perfectly describe me in Halo Custom Edition.. I'm there quit a bit. Played every day till the truck project.

 

[FordRanger1991]

It's working correctly. i had the signal and signal ground wires crossed on the O2 sensor... At least as far as I can tell. Fired it up tonight and no more miss.

Edit: The name is supposed to be funny. I use it when gaming.. It does however perfectly describe me in Halo Custom Edition.. I'm there quit a bit. Played every day till the truck project.

Well good gaming name lol
So last weekend I got the engine back together and it is ready to go into the truck! But I can't make it back home until spring break... Kinda sucks lol I have been without my truck for two months now...
Being in the engineering program at OSU I don't find to many weekends where I can make the 3.5 hour drive home to work on my truck.

One of these days (probably spring break) I will post pics and a page explaining the wires I had to re-pin on the engine bay harness so that people can look at it for help on their own swaps.

 

[Stavos]

So I'm actually doing the exact same swap, I'm not finding a 92 4.0 harness though....what I have found is a 92 Explorer 4.0 harness, will this work or should I keep searching.

Thanks, Steve

 

[FordRanger1991]

So I'm actually doing the exact same swap, I'm not finding a 92 4.0 harness though....what I have found is a 92 Explorer 4.0 harness, will this work or should I keep searching.

Thanks, Steve

Well you could definitely make that work. You should buy evtm manuals for both the 91 ranger and the 92 explorer. You will need to re-pin some things for the Engine bay harness but that shouldn't be do difficult. Just make sure you get the computer from the explorer also.

 

[Stavos]

Well you could definitely make that work. You should buy evtm manuals for both the 91 ranger and the 92 explorer. You will need to re-pin some things for the Engine bay harness but that shouldn't be do difficult. Just make sure you get the computer from the explorer also.

Thanks for the response! Got out to the salvage yard today and discovered that the donor is a 94 Explorer but still the square body style like the ranger, also has the same 4.0. Anyway was gonna get the harness, ECU and coil pack from it. I guess this will work as well shouldn't it?

Thanks again, Steve

 

[FordRanger1991]

Thanks for the response! Got out to the salvage yard today and discovered that the donor is a 94 Explorer but still the square body style like the ranger, also has the same 4.0. Anyway was gonna get the harness, ECU and coil pack from it. I guess this will work as well shouldn't it?

Thanks again, Steve

It depends on if you have a manual Transmission or not and if the explorer that your taking everything from is a manual or not. If your ranger is a manual you should be fine using an auto or manual computer from the explorer. I am unsure but it is possible that the 94 explorer put the ECU in the engine bay on the driver side (I know 93 and 94 rangers had them in the engine bay). This would just require you to make some sort of mount for the computer since your ranger would be expecting the ECU in the right passenger side kick panel. Hope that makes sense. Some quick thread searching should get you some more information on that. Also the 94 explorer will likely have smog crap and if it does then the computer will be expecting responses from the egr and the camshaft synchronizer. So... if the 94 engine you have isnt set up for California smog you will either need to fool the computer with some re-wiring of the egr wires (recommended: http://www.rjminjectiontech.com/collections/egr-eliminators) or you will need to take the egr stuff off the explorer which would be a pain... hope this helps.
Like I said, do some thread searches and you can find more information before taking only my word for it. I would'nt want to lead you wrong talking about something that I haven't specifically done. That being, using the explorer engine bay harness and comp.
But the above information should give you a great start.

 

[FordRanger1991]

The 4.0 Swap Done!

So I must say that this swap was totally worth it!
However, at times it seemed like a very tall expensive mountain.

Story on initial start up and run. (If you have already done a 4.0 swap, some of this may seem similar to your experience and you may not care to read this.)
So I made it home for the first week of spring break and I was stoked and excited to get that engine in my truck as fast as I could. All the wiring was done so all I needed to do was throw that engine in and start her up... or so I thought. Connecting the gas lines was a piece of cake and I didn't need to change anything for that. The exhaust also went on without any problems and the engine mounts for the 2.9 didn't need to be changed. Now the complications. When I finally had the engine in and mounted to the tranny, I began to connect all my electrical and install the radiator and the fan. I quickly noticed that some quick fabrication needed to be done in order to keep the 2.9 throttle cables. So a custom bracket was made to mount these cables to the manifold because the 4.0 had a different mounting bracket then the 2.9. (I can post a picture of this bracket if someone asks me to) After this, I began to install all the random things in the engine compartment like the intake and radiator and vacuum lines and power searing pump lines and so on... When I was installing the radiator I noticed that there was no clearance between the electric fan and the engine so I had to reverse the wiring on the fan to make it a pusher and mount it to the front of the radiator. With this I had to do a little trim job of some of the sheet metal in order to make it fit just right. (again I can post pictures of this radiator/fan set up if someone asks) By now everything was plugged in/hooked up and she was ready for some fluids and the initial start up. While filling the radiator it began to leak like a sieve. So i ran to the store and picked up a new radiator and filled it up and attempted to start it up for the first time. I turned the key and all she did was crank... no start... some quick trouble shooting figured out that I had no spark so I checked the ignition module and crankshaft position sensor for voltages and resistances. I had a bad Crank position sensor. I put a different one on that i had sitting around and then when to start her up...She fired up!! However... there was a really nasty grinding sound... the starter was shot and was not disengaging. So I ran to the store for a starter and then fired the engine up again. It was running but the throttle response had like a 2 second delay... installed a new TPS and the throttle response was fixed. Now it was time for the first test drive down the road. A quarter mile down the road my radiator cap popped up and shot anti freeze all over the windshield...(the hood had not yet been installed) I found that the cap was bad and was not sealing. To the store again! lol After the new cap I started her up again hoping not to run into any more problems (I had purchased the original radiator and starter from the same guy off Craigslist... needless to say I got ripped off and I will likely never buy mechanical crap from anyone on Craigslist again)...On the start I sat there listing and everything seemed to be running well except for a high idle around 1500 rpm Noticing that my temp gauge and oil pressure gauge were both not working I changed those sensors out with the sensors from my old 2.9 because they were the same. After that all my gauges worked properly. Anyways, after a few days of driving around town I was able to relax and see that I was in the green zone. It was a success!!
The power difference was amazing! With my 2.9 I always had to drop her down to 3rd gear while climbing the 6% grades on I5, Now I can climb them in 5th gear! I would say that is enough right there to prove the power difference.

Lastly, here is the page I used to figure out which pins I needed to re-pin in the main engine bay plug. Those 7 pins where the only part of the re-wiring process that actually required two seconds of thought. There were two plugs that had to be rewired on the driver side fender but they were color coded so it was easy as pie!

I am sorry this was so long but I just thought I would let everyone know about some of the issues you may face while doing a 4.0 swap.
I will post any pics that someone may need if it will help them.
Thanks to everyone that helped me out and who answered some questions.

I can now change my engine size below my avatar!!

 

[SenorNoob]

Congratulations! Isn't the 4.0 GREAT!? Reminds me I need to change my avatar.

Oh, did that fix your high idle too? I have (I think) the same problem but in my case it's 2000 rpm on my tach then when it drops below about 1000 it sounds like it's gonna die..

 

[FordRanger1991]

oh gosh yea the 4.0 is great! I did a little drag race with my bro who has a 2.9... needless to say he has already started looking for a 4.0 haha

So but no my idle problem still seems to be there even after replacing my IAC, Tps and cleaning both the throttle body and the MAF... on initial start up my truck revs to about 2500 rpm and then slowly drops to around 1000 when warm. Between shifts the idle doesn't drop either... when at a stop light the idle will only drop down to 1000 rpm if I am at a stop for at least 5 seconds (If I dont stop for the 5 seconds the idle wants to sit at around 1500 rpm). The motor also has new manifold gaskets that I installed after I replaced the head gaskets (followed the manuals torque specs and everything) The vacuum seems to be perfect though right at a perfectly steady 19-20 inches of mercury. I am a little confused because I really don't see how it would be possible to have a vacuum leak with new manifold gaskets and a good vacuum but that is what it seems like the problem is... a family friend suggested finding a cheap computer off eBay or something and plugging it in to see if that fixes the problem so I might give that a shot. Other than that the only other thing I can think of doing is trying to replace the lower manifold gasket again... I really don't feel like it haha

Thanks for the response though Noob!

For fun, today I checked the voltage output of the MAF at idle to make sure it was good... between A-B 13 volts and between C-D .8 volts... seems pretty sweet to me (if referencing the article in the tech library).
I will probably check my coolant and air temp sensors also because those could be doing something funny I guess.

 

[shorangerbird]

FR1991-is the wiring pic you show, the change for the rear lamps??? i am in the process of getting my swap started and i understand there is a change needed in the wiring on the left fender plugs to have rear lights work. also, how long/hard/easy is the harness swap, 2.9 to 4.0??? all day or hours?? thanks. your makes me ready to get mine done! oh, mine is in a '89 super cab, auto.....

 

[FordRanger1991]

FR1991-is the wiring pic you show, the change for the rear lamps??? i am in the process of getting my swap started and i understand there is a change needed in the wiring on the left fender plugs to have rear lights work. also, how long/hard/easy is the harness swap, 2.9 to 4.0??? all day or hours?? thanks. your makes me ready to get mine done! oh, mine is in a '89 super cab, auto.....

What year ranger are you getting engine,harness, and computer from? Wiring will probably differ a little...

These are the instructions when placing a 92 4.0 harness into a 91 original 2.9 truck...

Ok so When you get your engine bay harness from the donor vehicle notice the rear light plugs have differences between the 4.0 plug (singular) and the 2.9 Plugs (Plural) You will need to pull all the pins out of the 4.0 plug and re-pin them into the two plugs that the 2.9 harness originally had... this is really easy as Ford has color coordinated them for us. In the picture below you will see one big plug ( what the 4.0 harness originally had) that was removed and replaced with the two smaller plugs (taken from the 2.9 harness). This step is actually really simple...

Below is an image of what these plugs connect to once you re-pin the 4.0 harness into the two smaller plugs.

Below is an image of what the 4.0 donor truck harness. Notice how the picture above has the two smaller plugs once you do your re-pining.

Another thing that you will want to make sure of doing is taking the wiring that runs to the oil level gauge sensor, temp gauge sensor, the tranny reverse light switch, and the tranny neutral sensor because these plugs are different for the 2.9 and the 4.0 and the wires are not color coordinated. These two plugs run to the sensors/switches ( or whatever you want to call them) previously mentioned. Pictures shown below...

I hope that is clear...

The only other tricky part is to re-pin the main engine bay harness plug... but that really wasn't that hard either. If you need lay both the harnesses next to each other and figure out what the different wires are and then you know how to re-pin the 4.0 plug... I had to do that for a couple of the wires.

Lastly, when taking the 4.0 harness REMEMBER WERE ALL THE GROUNDS ARE. Take a lot of pictures and videos if you need. changing the harness is really not hard at all just remember where things go! This swap is really not that hard... You can do it!!!

Just for fun... the only HEEP part I will use

 

[shorangerbird]

-lol, sweet. i lke that. thanks for the info! my donor is actually a '91 explorer sport. picked it up from Co-part. it is a automatic on the column like my ranger. both are 2wd. i was thinking of removing the 2.9 harness first, starting on the RH side at the processor. that way i can understand how everything lays in. then, remove the explorer harness and TRY to reinstall it backwards of how it came out. do u think i should do my repinning before i put it in or after? or will it reall matter? anyways, thanks for the help. i want to try to start soon, as im basically waiting on my help who is removing the two engines for me, as he has the tools/lifts. then i will layin the harnesses and then he will put the engine back in. i may be back askin some moe questions though, if ya dont mind......thanks

 

[FordRanger1991]

-lol, sweet. i lke that. thanks for the info! my donor is actually a '91 explorer sport. picked it up from Co-part. it is a automatic on the column like my ranger. both are 2wd. i was thinking of removing the 2.9 harness first, starting on the RH side at the processor. that way i can understand how everything lays in. then, remove the explorer harness and TRY to reinstall it backwards of how it came out. do u think i should do my repinning before i put it in or after? or will it reall matter? anyways, thanks for the help. i want to try to start soon, as im basically waiting on my help who is removing the two engines for me, as he has the tools/lifts. then i will layin the harnesses and then he will put the engine back in. i may be back askin some moe questions though, if ya dont mind......thanks

Ya its no problem at all!
So ya starting with the 2.9 harness would probably be best. Disconnect the computer and work your way around from there. I think it would definitely be easier to re- pin the 4.0 harness while it is out of the truck... then you could lay it down next to the 2.9 harness. But it really is just whatever you feel like doing. It would also be easier to get the 4.0 harness in before the engine. After installing the 4.0 harness run through all the electrical stuff to make sure it works ( ex. Tail lights, reverse lights, blinkers... and so on).
Good luck!