The Polar Bear - NP241 Upgrade

[downtowncb]

Sure, no problem!

The 241 is all in and done, it fits up there nice and tight so it should be fairly well protected, even without the skid plate below it. It just needs a new rear drive shaft. I also haven't finished the frame side of the new motor mounts I posted about above.

[KM88]

Nice Jeep you have there and the mods you have done are awesome.

I have some questions though regarding the swap. I have an '96 ZJ with a 5.2 and I also happen to have a LQ4 in an other Jeep... well things are complicated and I have been thinking about putting the LQ4 into the ZJ.

How much of the original PCM did you need to keep in order to have a working dash? And what of the original features in the dash are not working after the swap?

The 5.2 is pretty dead compared to the Vortec and I'm not sure it's worth it to put any money into mods on the 5.2.

Thanks.

[downtowncb]

Nice Jeep you have there and the mods you have done are awesome.

I have some questions though regarding the swap. I have an '96 ZJ with a 5.2 and I also happen to have a LQ4 in an other Jeep... well things are complicated and I have been thinking about putting the LQ4 into the ZJ.

How much of the original PCM did you need to keep in order to have a working dash? And what of the original features in the dash are not working after the swap?

The 5.2 is pretty dead compared to the Vortec and I'm not sure it's worth it to put any money into mods on the 5.2.

Thanks.

Thank you!

I kept the original Jeep ECU and made a stripped down harness that I integrated into the Chevy harness to get the gauges to work. I removed the Chevy oil pressure sensor since the Chevy ECU doesn't need it to run and used a brass adapter to install the OEM Jeep sensor. For the coolant temp, there is a second port with a screw plug in the heads that I used another adapter to install an OEM Jeep coolant temp sensor. I couldn't replace the Chevy one, since the Chevy ECU needs it to run.

The speedometer uses the Jeep sensor installed in an NP241 t-case with a SYE kit.

I made a custom circuit to spoof the crank position sensor signal going to the Jeep ECU based on the output from the Chevy tach signal wire to get the dash tach to work. It's works most of the time, still some bugs to chase here; it took a lot of time to figure out.

I cut the trace on the gauge cluster PCB for the check engine light and then soldered the Chevy ECU's CEL output wire to the LED terminal.

After all of that everything in the cluster works.

Sensor adapters:
http://www.speedwaymotors.com/Auto-M...ter,20928.html
http://www.speedwaymotors.com/Auto-M...pter,8195.html

[KM88]

Okay, thanks for the reply.
So you're actually running both PCM's in parallel; keeping the 5.9 PCM for the dash functionality.

The stuff you are using for the tach, is that the Arduino chip you mentioned?

Kind of makes sense to just do the damn swap. I've been looking into methods on re-maping the 5.2 PCM to get more power and since there are no good ways to do that, the most cost efficient way would be to add a MS3 in parallel. Then I still would have the outdated 5.2 Magnum...

Thanks

[downtowncb]

Yes I programmed the Arduino to modulate the output to the Jeep ECU's tach signal input which is based on 152 pulses per revolution if my memory serves me correct (this was quite a while ago), based on the input from the Chevy ECU's tach signal which outputs 2 pulses per revolution. It is a software implementation of a phase locked loop. It is very difficult to get more power out of the 5.2 or 5.9 without a supercharger, and then tuning is a nightmare since there is no widely available way to modify the VE tables. These modern LS engines are way more powerful and fuel efficient. I get about 15-16 mpg on the highway in this jeep, and in the other one with the 5.9, I literally get 10 mpg...

[KM88]

It ain't cheap, but have you considered using the Novak tach emulator? (http://www.novak-adapt.com/catalog/e...h_emulator.htm)
I was thinking it might be possible by swapping out the PCM for one from a 6 cyl ZJ

[downtowncb]

It ain't cheap, but have you considered using the Novak tach emulator? (http://www.novak-adapt.com/catalog/e...h_emulator.htm)
I was thinking it might be possible by swapping out the PCM for one from a 6 cyl ZJ

No shit, haha! They didn't have that when I was doing the swap or I would have just bought it instead of creating my own. From the description I'm sure it does exactly what my little setup does.

I don't know if the i6 and V8 have the same number of teeth on the fly wheel for the crank position sensor, but if they do then this device will work on a V8 Jeep too. If not just call them up and see if they can sell one that outputs the correct number of pulses per revolution for the V8. If they are making these in house then it would be dead simple to modify the programming for a V8.

[Tuzmaster]

I'd like to resurrect this old thread. When you were doing the swap, did you try to come up with schematics between Chevy PCM and Jeeps? If, how did you go about figuring out what signal goes where? And what each one means?

Also, any update?????

[Kraqa]

good questions. id also like to know

[Wolfeman781992]

Holy hell this thread is full of good stuff, I definitely know what's replacing the blown 4.0 in my ZJ, only question I have is mines a 94....OBD1 How would I get my factory gauges to work with this, also curious how long my d30lp/d35 would hold up to this until I can swap in something better

[Wolfeman781992]

Also I never saw anything about how you wired up the trans

[Wolfeman781992]

Nice Jeep you have there and the mods you have done are awesome.

I have some questions though regarding the swap. I have an '96 ZJ with a 5.2 and I also happen to have a LQ4 in an other Jeep... well things are complicated and I have been thinking about putting the LQ4 into the ZJ.

How much of the original PCM did you need to keep in order to have a working dash? And what of the original features in the dash are not working after the swap?

The 5.2 is pretty dead compared to the Vortec and I'm not sure it's worth it to put any money into mods on the 5.2.

Thanks.

How tight was fitting the LQ4 in a ZJ?