ranger 3.0 needs new computer.. help!

[02ranger3.0]

Hello, I have a 2002 ford ranger 3.0. I bought the truck and then realized the truck was running rich, which was chased down to the bank 1 O2 sensor not working, which was a result of a bad computer. The truck has a motor from a 99 or older which is still the 3.0, but come to find out the 2002 computer thats in the truck doesnt match with the 99 and older engine which is causing my problem. I would like to buy a computer that matches so my O2 sensors work properly, but the problem is there is no way of knowing what this motor is out of. there is about 10 different computer options just for the 3.0 with a 5 speed tranny, 4x4, ect. and im not sure which one goes with this engine. What I need to know, is any or all of the computers compatible with each other for this engine? or is there a serial number/identification number somewhere stamped on the motor, in which i could try to find out what exact motor this is?
any help is much appreciated, thanks.

 

[Rearanger]

is there a serial number/identification number somewhere stamped on the motor, in which i could try to find out what exact motor this is?

There is. The engine number is recorded with the body number to help prevent thieves from chopping autos and selling parts. If a new motor was put in that should have been done through your state DMV and the truck's title.

You can get the engine number and contact Ford or maybe a local dealer to see what computer was used with that engine. The dealer parts counter should be able to match parts from the VIN, but not sure about engine number.

 

[JP02XLT]

You may have a computer issue, but I can tell you that as long as all the sensors are connected the computer does not know any difference in model year of the engine, generally the only change to the sensor will be a connector change for year to year changes. My 2002 has a 2007 Taurus engine, I used almost all the sensors from the 07 block. I also have an IAT sensor installed after the supercharger that is from a 92 Mustang v8 and the computer accepts the signal just like the stock unit in the MAF and the ECU adjusts everything accordingly.

If your seeing a rich condition I would start checking plugs, wires look for vacuum leaks, then move to the injectors, etc. You did not mention a specific code that was registered, but if an O2 is not working I would be checking the wiring as well as the O2 unit, prior to replacing the computer and expecting a miracle fix.

Another issue that may be your problem is the injectors themselves, poor condition, or the wrong sized units for a 3.0, although any Vulcan 3.0 injector other than a 3.0 flex-fuel injector should run just fine if the engine is in good mechanical condition.

As Rearanger stated there are ID numbers on the block, but other than a warm fuzzy feeling, I dont think that knowledge is going to do anything for you.

JP02XLT

 

[RonD]

That is a BIG JUMP, from Bank 1 Rich to "need new computer"

You can not change the computer, 2002 will have an anti-theft system(PATS) so computer is married to the PATS system, a Ford Dealer is the only place a computer can be remarried, you can supply the new computer and they will just charge shop time to remarry it, but it will take 1.5 to 2 hours time.

Truck will not start with new computer in place, just FYI, so don't change it if truck is running now, get it to the Ford Dealer first or it will have to be towed there.

This is not the same as adding PATS keys, the PATS module and computer are "married" at the factory, so neither can be swap separately, you could swap PATS module and computer from another vehicle as a set, but you would also need the PATS keys from that vehicle or a locksmith with Ford software to add your current PATS keys to system.
No, the locksmith can't remarry computers/PATS module, that requires an active subscription to Ford's Data base, so Ford Dealers only

 

[Tractor Dan]

Not meaning to steal the thread but just curious and i'm sure you can answer this Ron. If remarrying a setup like in this case is there a cutoff point on how far back they can go? Like since the OP's truck is a 2002 would the dealer be able to do that since it's older than 10 years? I ask because the topic of how long dealers keep information and can access things has come up in multiple automotive classes i'm taking. Most commonly in regards to PATS keys. I haven't got into classes dealing with computers yet so that's why i'm fairly green there. Again sorry but wanted to ask that and figured it may be helpful to the OP just in case there is a cut off and even ford couldn't help.

 

[02ranger3.0]

thanks alot guys for all the information. The reason why I believe it is the computer is because the truck just spent a week and a half in a local shop, which i actually work part time at. They traced all the wires, tested and checked all the injectors, checked the egr valve, replaced and tested the O2 sensors and even tried switching them from side to side to see if the problem would go from bank 1 to bank 2 and it didnt. They found no electrical problem or anything else, between the 3 mechanics that worked on it, and when tested with a scan tool, and watching all the sensors displayed on the screen, it shows that there is a problem with the bank 1 O2 sensor, and they traced this down to being a computer issue. And I dont believe the engine was replaced at a dealer or somewhere "professional" because its kind of just thrown together, as wires are everywhere and what not.

 

[JP02XLT]

If you have access to a scanner that you can data log the O2's while your driving I would do so, O2's can get terribly slow reacting and still test ok with a DVM meter. I have seen scanners that have trouble correctly identifying the correct O2 sensors in systems, Fords software in the ECU is a bit on the troublesome / sketchy side for reading codes with anything less than a Rotunda (Ford) Scanner

If the wiring is a mess I would start cleaning it up and check all the connections and for any damaged/pinched wires.

You can also check the output signals of the computer going to the O2, signal is 5v, and the signal ground, that the ECU measures the voltage differential to determine O2 state, and a 12v & ground for the heater circuit in the O2. Only 4 wires, easy to check the condition. Should eliminate or confirm an ECU problem real fast

Wiring issues are a pain, especially to find, most of the time they can be easily repaired.

Another thing I would check for is a contaminated MAF sensor

JP02XLT

 

[RonD]

Not meaning to steal the thread but just curious and i'm sure you can answer this Ron. If remarrying a setup like in this case is there a cutoff point on how far back they can go? Like since the OP's truck is a 2002 would the dealer be able to do that since it's older than 10 years? I ask because the topic of how long dealers keep information and can access things has come up in multiple automotive classes i'm taking. Most commonly in regards to PATS keys. I haven't got into classes dealing with computers yet so that's why i'm fairly green there. Again sorry but wanted to ask that and figured it may be helpful to the OP just in case there is a cut off and even ford couldn't help.

The remarrying is not vehicle year/model specific.
The new computer needs to have the correct software for the vehicles options, i.e. engine/trans, but that's not part of the PATS.

The PATS module and Computer have to "handshake" when powered on, so both recognize the other and know each hasn't been tampered with, the point of an anti-theft system.
The remarrying erases the marrying done at the factory and then renews the "handshake" so both units recognize each other, they are remarried.
The Ford Data base is needed to do this, but not because of the year of the vehicle, it isn't time based, it is done to lessen the chance of a hacker being able to remarry the units, all the info needed to remarry is not in the module or computer.
The time it takes to do this is 20-40minutes, if it works the first time, and it doesn't always work the first time.
This is on purpose, the time delay and if there is any "glitch" in the process, it resets, this is done to lessen the chance of a hacker disabling the PATS quickly.

PATS keys have an embedded RFID tag(google: RFID), so each key has it's own unique RFID number, the ID numbers are added to the PATS system in a vehicle.
Once added the PATS system it will allow engine to start if that key is used, most PATS systems have enough memory for 8 RFID keys, but it can be erased and keys re-added if full.
If you have 2 working PATS keys, with different RFID numbers, you can add a 3rd yourself.
The key part can be cut by any key cutter from old key to match key switch, then follow instructions for your model of PATS to add 3rd key.
Ford Dealers and many locksmiths have the software to add PATS keys to the PATS system.
This is not model year specific either, a 2014 PATS key can be cut and added to a 2002 PATS system.

You can also "clone" PATS keys, if you are down to 1 key and don't want to pay to add another to the PATS system.
You can buy Blank RFID keys, have it cut for ignition switch and then read the working key's RFID tag number and write it to the Blank RFID tag.
So both keys have the same RFID number, and will both work to start engine.
This won't allow you to add a 3rd key to PATS system since you need 2 different, and working, RFID numbers to add a 3rd.
But the point of cloning is having a back up key, and it does do that.