1994 Ranger 4.0L MT EMC questions

[94RangerPerson]

Ok, this is a cheapie truck. And I am trying to keep it that way. I bought it year ago with worn out clutch. Started fine and engine sounded good. I knew nothing about this generation Ranger. Replaced clutch myself. Drove but tranny pretty noisy and would pop out of first, and fifth screamed like banshee. Seller hadnt mentioned this of course. Mr. Lucas quieted it down. Then got hot stall at idle, though usually will drive fine down hiway on shorter trips. It will bog down noticably on longer drive where lucky to get it over 40mph on a hill. I finally got rpm I wanted and unplugged the IAC. Kept it at 750rpm cold or hot. Have to feather pedal cold but keeps from stalling at hot idle. Replaced oxygen sensors, fuel pump, fuel pressure regulator, throttle position sensor and couple other things. MAF looked shiney and new, assume previous owner had replaced it. Read codes.

Only weird one was complaining about non functional EGR. Strange as this truck is federal emissions and no EGR on it, no place to put one. There is a round flat raised place in drivers manifold casting that I assume is where they drill and thread hole for the EGR tube, but it was never drilled.

Anyway around June transmission blows, no huge surprise. I actually liked way the truck handled so kinda wanted to fix it. I got this idea I wanted a heavier duty tranny instead of the super light duty they put in it at factory. Way its geared, I dont really need overdrive anyway. Spent time, off an on, adapting a SM420 I had setting around out of an early 60s Chevy pickup. Its definitely hard to kill one of those.

So thats done, but got to thinking about drivability quirks and recently pulled the ECM. Ran the sticker code on google and thing is out of a 1994 Explorer with MT and EGR. Ok, that explains the EGR fault code. I am guessing besides that it isnt reading some of sensors correctly.

Reading online, seems using ECM for EGR truck not good for truck without EGR. Some stuff besides just throwing a code. No sign of a cheap federal emissions ECM for a Ranger without EGR. Manual tranny 4.0L seem kinda rare. They want half what I paid for the truck at the parts stores for rebuilt one and I am not absolutely sure what exact ECM came in the thing from factory.

So is there any problem using ECM for an automatic other than it throwing a code cause it doesnt detect an automatic? I dont have emissions inspection so for now such a code is meaningless legally. How about a 1993 federal emissiosn Explorer ECM. Or 1993 or 1994 ECM from an Aerostar? I even ran across a thread on this topic somewhere, some guy said he was running his 4.0L Ranger with a 3.0L ECM. Well, both OHV 6cyl engines, I can see where that would possibly work if right wires from sensors went to the right pins on the ECM??? Those are very easy to find for manual transmission and no EGR and pretty cheap.

 

[94RangerPerson]

Oh should also mention this thing gets horrible gas mileage. 12 to 14mpg at best. My old 4wd F250 gets 13mpg going down hiway with a carburetor so I am so not impressed with Ranger 4.0L fuel mileage.

 

[RangerX]

Can't help you at all with the ecm, but have some questions on the mpg, it should be better. Are you running stock size tires and factory axle gears? Where did you plug the speedo cable in on the sm420? Is your speedo accurate?

 

[Josh P]

When I did a manual transmission swap in my aerostar van I used a ranger ecm. I searched on car-part.com for the cheapest junk yard that would ship which was $45 to my door.

 

[94RangerPerson]

Can't help you at all with the ecm, but have some questions on the mpg, it should be better. Are you running stock size tires and factory axle gears? Where did you plug the speedo cable in on the sm420? Is your speedo accurate?

Yea, stock tires, I think its 3.36:1 axle ratio, something close to that. Thats why dont need 5spd, even transmission that came with it, I only tried 5th out of curiosity, quickly found out besides the noise, it was kinda worthless with that axle ratio. I rarely go over 60mph. If one was going to use 5th in this truck, you would want like 3.75:1 axle.

The fuel mileage is year ago, I havent driven it much yet with the SM420. And drive by tachometer, certain rpm in certain gear..., so wont really know miles driven unless I use one of those android speedometer apps.

 

[94RangerPerson]

When I did a manual transmission swap in my aerostar van I used a ranger ecm. I searched on car-part.com for the cheapest junk yard that would ship which was $45 to my door.

Trying to find a 93/94 Ranger ecm for federal emissions 4.0L with manual for reasonable cost seems difficult. Cheapest I found on ebay was like $150. Parts stores want more. And zero to be found in local yards, most are automatic or ecm gone already. Fewer made and seem popular for manual conversions.

Thats why I am wondering if one from 93/94 automatic Ranger/Aerostar or 93 Explorer would work. I am also not certain the one that came in the truck, the one for 94 Explorer with EGR, is bad or just not fully compatible. Its like it isnt reading some of sensor signals properly. Course it may just be trying to compensate for what it sees as missing EGR.

From what I am finding online, seems like federal non-egr automatic ecm will work, but used with manual transmission has some quirks. Getting one that is non-egr seems more important than being for manual transmission.

I am old man and still be lot more comfortable tuning a carburetor than playing games with automotive electronics. I understand basically how they work, just seems unecessarily complex way to do same thing that used to be lot simpler. But suppose its lot about what one grew up with and is used to working with.

I know I could tune an old carburetor straight six to get 18 to 20 mpg in vehicle this size and weight. So with all the electonics to have it get 12 to 14 seems odd. And pure fantasy that any vehicle using more fuel per mile is going to pollute less per mile. You might get less of certain components of combustion process, but not less total combustion product out the tailpipe.

 

[Josh P]

The 4.0L with egr has a cam sync sensor and sequential fuel injection, that ecm won't work correctly with your truck. F47F-12A650-CMA is a fed emissions ecm that is listed for 2 or 4 wheel drive manual transmission. Holly auto parts has one on the shelf for $75 and they will ship. the phone # is 248-634-1940.

 

[94RangerPerson]

The 4.0L with egr has a cam sync sensor and sequential fuel injection, that ecm won't work correctly with your truck. F47F-12A650-CMA is a fed emissions ecm that is listed for 2 or 4 wheel drive manual transmission. Holly auto parts has one on the shelf for $75 and they will ship. the phone # is 248-634-1940.

Thank you. That is cheapest I have seen though guessing shipping will get that lot closer to $100. I did find a non-egr one for automatic Aerostar that is on its way for $23 shipped off ebay. I want to try it first. But have feeling I will probably end up ordering the one you suggest. Sometimes just got to try a couple cheap options before ponying up and doing it the right way. And I suspect one you suggest is the right one. At worst, I will have learned something for my $23.

So also if I get you right, its rather a miracle that the Explorer ecm with EGR I have been using worked at all? Perhaps it is mainly running in "limp home" mode? That would explain it running rich and poor fuel mileage. Cause way I drive and speeds I drive, it shouldnt get less than 16mpg.

 

[94RangerPerson]

Little update. Ok got a $23 ECM for 1993 Aerostar 3.0L with automatic. After I found that thread mentioning successfully using a 3.0L ECM to run a 4.0L, had to try it since they are so plentiful and cheap. Plugged it in. Ran bit funky, then remembered IAC was unplugged to keep it from stalling with former ECM. Plugged it and idle speed went to 1000, and engine ran real smooth. Engine warmed up and idle down around 500 to 600. Drove it. Runs great. Of course being for an automatic it does throw codes cause its not getting signals from automatic transmission. But I dont much care, dont have emissions inspection in this state.

But my SM420 started making squeal when cold. And after few mile trip to post office and home, notice it was very hot to the touch. Yea, think there is a bad internal bearing, as these dont normally get this hot even under heavy use. Should have put kit in it before installing it. These are very old transmissions at this point and this one had set outside for decade or so, had bit rain water and bit rust. I cleaned it out and put in fresh lube. But should disassembled it and checked it thoroughly. So I get to pull it. I have another that I checked and has no signs of water or corrosion. Will put it in I guess. Quicker and cheaper than putting kit in this one, especially if the bad bearing wore down a shaft.

Otherwise it drove fine with the SM420. Its just a very different transmission than the light duty five speed that came in the truck. Wouldnt be for everybody, but I knew what they are like to drive. I had a 1960 Chevy Apache at one time with a 235-6 and SM420. Driving Ranger with this transmission brought back memories.

As much as this truck weighs (more than the old full size Chevy) and size of this engine, still no idea why in world Ford didnt use the heavier duty 5spd offered in the F150. Sure the light duty 5spd is fine for four cylinder and maybe even the 3.0L, but marginal with the 4.0L.

 

[Josh P]

I'm impressed, thanks for the update