replacing computer

I wan't to replace my computer in a 98 windstar. I think its under the hood on pass side.
I see the wire conector and looks to be two bolts that hold the harness on. Does it slide out from engine side? Also how important is it to replace with same model numbers as there look to be about 20 different ones. My problem is the van will not run right unless I disconnect battery and reset it. How much does a used one run?

I wan't to replace my computer in a 98 windstar. I think its under the hood on pass side.
I see the wire conector and looks to be two bolts that hold the harness on. Does it slide out from engine side? Also how important is it to replace with same model numbers as there look to be about 20 different ones. My problem is the van will not run right unless I disconnect battery and reset it. How much does a used one run?

GUS

What do you mean the "van will not run right unless I disconnect battery and reset it". What does not running right mean? Running rough? Stalling? Not starting well?

What are you resetting? Codes?

I would think that a used one would run around 30.00 to 100.00 depending on where you get it.

Regards

Dan

If the van won't run right unless you reset the computer, this likely means there's some problem with the engine that needs to be fixed. Resetting the power returns the computer to its default factory configuration. After running for awhile, the computer 'learns' settings required for your engine and environment (idle settings, spark and timing parameters, etc.).

Unless you can prove that there's something specifically wrong with the computer itself - and not the engine its attached to - I suspect a replacement computer will exhibit the same symptoms you're seeing now.

Is the check engine light on after the van runs for awhile (i.e., when it starts running poorly)? I suspect it is. Get the error codes dumped (I believe most Autozones will do it for free) and start diagnosing from there. It's rare for an engine controller to fail in the manner your situation suggests.

I also believe that there is a PCU self test and that if any of the I/O ports are not reading correctly it will be flagged. If the computer has a hard circuit board type failure then I doubt resetting the PCU via a battery disconnect would help.

In other words I agree with the post that suggest getting the codes read (if any) and diagnosing from there.

GL

Yes I too would have the problem checked out..Do you have a engine light on??? Going back a little the cars I have seen with bad cpu would turn over but would not start at all..

GUS

What do you mean the "van will not run right unless I disconnect battery and reset it". What does not running right mean? Running rough? Stalling? Not starting well?

What are you resetting? Codes?

I would think that a used one would run around 30.00 to 100.00 depending on where you get it.

Regards

Dan
Dan, I had this in a ford shop for a NYS inspection. They replaced mass air fow sensor, o2 sensor and upper intake gasket. Then tried to hookup to state for inspection. Would not. They reset computer and did drive cycle and when they shut off engine to hook up the computer resets its self.
When I reset and drive ,it runs fine. Turn engine off and restart it runs rough chugs and spits out soot when driving and cel comes back on.I stop and disconnect battery and runs fine again. The 98 engine was replaced with a 99 or 2000 . Thats when problems started.

Dan, I had this in a ford shop for a NYS inspection. They replaced mass air fow sensor, o2 sensor and upper intake gasket. Then tried to hookup to state for inspection. Would not. They reset computer and did drive cycle and when they shut off engine to hook up the computer resets its self.
When I reset and drive ,it runs fine. Turn engine off and restart it runs rough chugs and spits out soot when driving and cel comes back on.I stop and disconnect battery and runs fine again. The 98 engine was replaced with a 99 or 2000 . Thats when problems started.

Gus

The engine replacement is new information. I would hope that a 98 is the same as a 99 or 2000. (this is where I'm hoping someone else will chime in) If not we may have incombatity issues with some controls. Did the probem happen right after the engine was installed? Or were you able to drive for a while?

It sounds like it's getting too much fuel. I would look in the fuel metering areas. ie..fuel psi reg. fuel injectors....

Regards

Dan

Dan, I had this in a ford shop for a NYS inspection. They replaced mass air fow sensor, o2 sensor and upper intake gasket. Then tried to hookup to state for inspection. Would not. They reset computer and did drive cycle and when they shut off engine to hook up the computer resets its self.
When I reset and drive ,it runs fine. Turn engine off and restart it runs rough chugs and spits out soot when driving and cel comes back on.I stop and disconnect battery and runs fine again. The 98 engine was replaced with a 99 or 2000 . Thats when problems started.

Okay so I think I understand.......you have a 99 or 2000 engine running connected to a 98 PCM. This could cause problems (although perhaps not). What I do not understand though is why resetting the PCM allows it to run until the drive parameters are re-learned.

Did you replace the entire engine sensors and all? or just the block (block and heads....) The PCM should not care too much about these but if you connecter a whole different set of sensors from a different year it could cause some compatibility issues.

I suppose though you really just want an answer to how to remove the PCM. I don't know the answer but I assure you that all of the posters are just trying to avoid having you spend unnecessary money.

Gus

The engine replacement is new information. I would hope that a 98 is the same as a 99 or 2000. (this is where I'm hoping someone else will chime in) If not we may have incombatity issues with some controls. Did the probem happen right after the engine was installed? Or were you able to drive for a while?

It sounds like it's getting too much fuel. I would look in the fuel metering areas. ie..fuel psi reg. fuel injectors....

Regards

Dan
When I got it back from engine replacement did not run this bad. When mass air flow o2 sensors and intate gaskets were replaced is when it realy got bad. Ford is even puzzled with this. They say the computer keeps reseting its self when I turn off engine. I thought computer is looking for a sensor thats not on this motor.Thats why I do not know what pcm to put back in. Motor was shipped from a bone yard in New Jersy. I have allready put about $4500 in this.

When I got it back from engine replacement did not run this bad. When mass air flow o2 sensors and intate gaskets were replaced is when it realy got bad. Ford is even puzzled with this. They say the computer keeps reseting its self when I turn off engine. I thought computer is looking for a sensor thats not on this motor.Thats why I do not know what pcm to put back in. Motor was shipped from a bone yard in New Jersy. I have allready put about $4500 in this.

Gus

You probably already know this but I believe you're way over budget for the value of this van. I hope it's in excelent shape! I also hope we can find a solution for this.

Who replaced the engine?

When Ford replaced the parts did they know it wasn't the orginal engine or an engine from the same year?

Regards

Dan

1999 was a major change year.
Totally different intake manifold, moved a few other things around.
I do not know what all they changed.....but you might want to check with FORD to see how the 1998 and 1999 part numbers for the PCM compare.....and if they know of any differences.

You might also try to get the wiring diagram for the 1998 and 1999......the page with the PCM pin-outs and see if they match up.

Other things to compare......perhaps by looking up these parts (you can do it online) for the 1998, and then the 1999....and see if they are the same.....
1. Mass Airflow Sensor (MAF)
2. Oxygen sensors
3. Fuel injector

There are other parts one could check.....but I am thinking....that the response of parts (voltage range to the PCM inputs.....how much a fuel injector sprays for a given signal) could be a factor.

I would think that the FORD service department would know something was a-miss as soon as they lifted the hood. Body style was MUCH different between 1998 and 1999, and the engine looks much different.

How much data there is out there as to the cross-referencing of parts between the may be an issue.

1999 was a major change year.
Totally different intake manifold, moved a few other things around.
I do not know what all they changed.....but you might want to check with FORD to see how the 1998 and 1999 part numbers for the PCM compare.....and if they know of any differences.

You might also try to get the wiring diagram for the 1998 and 1999......the page with the PCM pin-outs and see if they match up.

Other things to compare......perhaps by looking up these parts (you can do it online) for the 1998, and then the 1999....and see if they are the same.....
1. Mass Airflow Sensor (MAF)
2. Oxygen sensors
3. Fuel injector

There are other parts one could check.....but I am thinking....that the response of parts (voltage range to the PCM inputs.....how much a fuel injector sprays for a given signal) could be a factor.

I would think that the FORD service department would know something was a-miss as soon as they lifted the hood. Body style was MUCH different between 1998 and 1999, and the engine looks much different.

How much data there is out there as to the cross-referencing of parts between the may be an issue.
Thats new info. What if I took one last dive into this and got a used pcm from a 99 and tried it. ....... Are they easy to swap out? For a few more bucks maybe its worth a try.

This is WAY over my head....as to compatiblility between years for the computer. Of course....if you can get one cheap....it is worth a try.

This is WAY over my head....as to compatiblility between years for the computer. Of course....if you can get one cheap....it is worth a try.
how can I find out the year motor I have? Is it stamped somewhere?

The dealer should be able to tell from the serial number....if you can find it. The dealership should know where to look....and how to look it up.

My guess is it would be easier to make the engine sensors match the '98 PCM than to install a '99, or later, PCM.

"Installing" the '99 PCM may not be the issue ... beginning (I think) in '99 the control hierarchy is co-managed between the instrument cluster, the PCM, and the transponder at the key tumbler. Putting this altogether is an awesome task ... I THINK ... as I know very little of what I speak here.

I agree and I tried to suggest this earlier.

Why not just use the block from the replacement and transfer all of the bolt ons (Intake, exhaust........from the original. this way all of the sensors transfer over.