93 engine in 92 explorer PCM question

[Critter92X]

I have a 92x that I installed a 93x engine in,everything seems to be working right.It runs good, gets 16-17mpg.But after reading in here about the differences between the 92-93 I'm wondering if I should change to the 93 PCM.
I currently still have the 92 PCM in it and the original exhaust with just one o2 sensor.Should I change that too? The only issue I seem to have( I posted it in the tranny forum, maybe wrong place?) is my CEL was coming on. I checked it
and I'm getting codes 522=vehicle not in park or neutral during KOEO-it was in park..and 629=CCS circuit fault or lock-up solenoid circut fault. I haven't noticed anything wrong with the TC.It seems to stay in OD and it doesn't shift back and forth or rev up and down during driving like I would expect if it isn't locking.It doesn't seem to be staying locked either it doesn't pull down when I stop at a stop sign or try to die when I put it in gear.I don't really understand what the codes are trying to tell me. Could it be the PCM reading the wrong signals since
it's not the right setup?I couldn't get any signal at all for the KOER test but maybe I was doing something wrong.It doesn't seem to be a problem other than the CEL driving me nuts. Ideas anyone? Thanks

 

[MrShorty]

How much from the '93 did you install? '91 to '94 all use the same engine block, so you should be able to install the '93 in such a way that it looks/operates exactly like a '92.

 

[ExplorerDMB]

It is usually good to keep the same year and calibration code the same as with the engine. Maximizes performance and fuel consumption. Computers have a set memory and ways to do things, even if the memory is a little different between the two by a half a volt, that may allow you to lose 1 mpg or something that we consider vital. I will keep your transmission post in the transmission section as it's realatively two different questions - just keep it to what section your under. Don't talk about the transmission issue in this section. Good luck

-Drew

 

[Critter92X]

Thanks... It sounds like I should put the PCM on for the 93.Everything on the engine is from the 93, I used the long block and kept everything on it.So if I change the PCM I guess I should also change the exhaust and put in both o2 sensors?

 

[410Fortune]

the 93 PCM does not use EGR, so you can remove that sucker and plug the exhaust manifold where it is attached.

You will need to run additional wires for the second 02 sensor to the PCM

Also be careful as some of the pinout locations may have changed on your 92 PCM to the 93 PCM. You might consider just keeping the 92 PCM and fix your trouble codes.
You kept the 92 transmission and wiring correct? All you did was install a 93 long block in place of your 92 long block? What I am getting at is you kept ALL of the 92 wiring, right?

 

[Critter92X]

Yes i kept the 92 wiring and just switched the long blocks.Everything seems to be working allright I just wondered if it might give me some trouble down the road with the few differences between the 92 and 93.

 

[410Fortune]

differences? As far as the block goes? 93 has no EGR and has dual 02 sensors.
Not a big deal IMO, the 93 block has the updated heads too.

the 92 computer likely has a more aggressive profile as well, I know several people who went from a 91 Explorer to a 93-94 Explorer and swear up and down the 91 had more balls.

Fix your codes and stick with the 92 wiring and PCM IMO.
Dual 02 sensors is just another thing to replace. Sure it may give the computer a more accurate picture of the two banks, but thats not always a good thing....I mean what does it gain you? 1/16th of a MPG? come on we are talking a 13 year old truck, MPG is not the big concern. Slightly better throttle response (computer can react quicker to air/fuel changes). Not worth the hassle IMO.

the big advantage in the 93-94 wiring is the waterproof relay and fuse box, if you do anything, swap out your crappy 92 fuse panel with the 93 box, will also give you additional fuse and relay locations for adding accessores and wiring them in like factory.

Next time you run the KOER test, shift the truck from P to N and see if that code goes away.
Also the BOO code muight be because you never depressed the brake pedal during the test?

When you run the test it promopts you to turn the wheel, hit the brake, etc etc. If you dont do it codes will appear. I just ignore those suckers.

As long as the same trans and trans wiring is in place these codes should not be related to the new engine. It might be you pinched some wires or something during installation, in this case I would check the continuity between the swtiches/sensors and the PCM main plug to make sure the signal is getting through. The BOO switch is on the brake pedal and the gear selector switches are in the A4LD trans (I believe, I dont think the column shifter has a sensor in it?)

 

[Critter92X]

Thanks for the input. I guess I'll leave it as is on the PCM.Yea it seems to have more power than before but I am comparing it to a motor that was about wore out.I'll take your advise on the fuse panel that sounds like a good idea.I'll check my wires it's possible I pinched one.When I did the KOER I tried P and N and I did pump the brakes and turn the wheel and hold it 10 seconds. I wasn't sure if I had the BOO or the PSPS, so if in doubt try it I guess.But I couldn't even get the engine ID code to come up.I'll try running down some wires and go from there,it usually turns out to be something obvious and simple that I overlooked...Thanks again