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Changing my MJ to a GM computer sys.


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So, if I'm reading correctly, I can run a inline 6 on a 12200411 pcm.
I'll need to put a 3x crank trigger and a 1x cam signal.
If I'm reading correctly, I can run port fuel injection and a distributor for ignition.
Can anyone confirm this? Has anyone ever done this?
I've read several posts where people said they were going to do this but they never finished the project or just never posted that they did.
I'll be machining my own crank reluctor and maybe building a custom distributor. The pcm I'll be using is a 12200411 pcm with a 4.3l V6 bin.

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Where did you find this? If you don’t mind me asking. All we know is that the 86’s with the 2.8L can be swapped around to the 3.4L and have possible fuel injection along with a carb with little to no modifications. But as for an AMC 4.0L running on a GM ECU seems a little blasphemous. 

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2 minutes ago, eaglescout526 said:

Where did you find this? If you don’t mind me asking. All we know is that the 86’s with the 2.8L can be swapped around to the 3.4L and have possible fuel injection along with a carb with little to no modifications. But as for an AMC 4.0L running on a GM ECU seems a little blasphemous. 

I don't know about "blasphemous" but if I can do it, I'll be able to tune it with software I already have. 

There is a tuning software ( https://www.tunerpro.net/features.htm ) you can download, cheap, out there. There is also a transfer software ( PCMHammer https://pcmhacking.net/forums/viewtopic.php?f=42&t=7378 ) you can download free. Both of these work great. They give me the ability to upload, download and tune the files in the 12200411 GM PCM. Gm used this PCM to run a lot of different vehicles and engines.

I've been reading on several forums about what they are capable of. Check out http://gearhead-efi.com/Fuel-Injection/forumdisplay.php?32-OBDII-Tuning, https://pcmhacking.net/forums/viewforum.php?f=42, https://ls1tech.com/forums/fueling-injection-8/. There's a lot of information on tuning. There's just not much about Jeeps.

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2 hours ago, Pete M said:

'tis an interesting idea.  I wonder how flexible that computer is for the various sensor inputs. 

 From talking to a few LS guys and reading on the forums I listed above they are pretty amazing. People replace earlier computers with these. 

 

I'm going to try and run just the engine as a stand alone. It'll have a 02 sensor, a cam position sensor, a crank position sensor, speed sensor and a water temp sensor. 

 

I may end up adding other things, I just don't know yet. But I'm going to be running sequential fuel injection.

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4 hours ago, Pete M said:

I like this idea. :L:  keep us posted on your findings!  this might be an awesome upgrade for those running strokers or blowers.

 I'll do it. I'm not much for taking pics but I'll fill ya in on the technical stuff.

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The ecu itself I have no doubt could run the engine but it’s comparability with the HO crank reluctor pattern I find dubious. That crank pattern is is only somewhat close to a Subaru reluctor. Unless we’re talking a Renix reluctor?? There are many stand alone ecu’s that will run the 4.0 (especially in batched mode) but most are not able to integrate with the stock HO cam and crank triggers. Aside from that, I don’t see what would be gained by using a GM ecu. Even the old SBEC ecu’s can be socketed and tuned. Renix is the only system that would need a piggyback to tune.  

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2 hours ago, ghetdjc320 said:

The ecu itself I have no doubt could run the engine but it’s comparability with the HO crank reluctor pattern I find dubious. That crank pattern is is only somewhat close to a Subaru reluctor. Unless we’re talking a Renix reluctor?? There are many stand alone ecu’s that will run the 4.0 (especially in batched mode) but most are not able to integrate with the stock HO cam and crank triggers. Aside from that, I don’t see what would be gained by using a GM ecu. Even the old SBEC ecu’s can be socketed and tuned. Renix is the only system that would need a piggyback to tune.  

I won't be using any Renix or HO reluctors or sensors. I'm going to be using GM and custom parts. And I'm doing it to see if it'll work. 

I've got nothing to loose, it won't run now. And I'm not going to spend the time and money on replacing everything on this truck with factory parts. 

If I'm going to spend that much time on a project, I want it to be a little more modern than the Renix system when I finish.

 

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13 minutes ago, omega_rugal said:

of course you can as long as you put the sensors at the right places

 

i don't know why you want to put yourself through this, you love that system that much?

It's not that I love that system that much. It's that, that system is so much easier to use than a Renix. 

The parts are easy to find anywhere. And the system is so flex able it just crazy. 

It's an OBDII system. I can hook up to it with my phone if I want/need to.

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42 minutes ago, Thorwon said:

I won't be using any Renix or HO reluctors or sensors. I'm going to be using GM and custom parts. And I'm doing it to see if it'll work. 

I've got nothing to loose, it won't run now. And I'm not going to spend the time and money on replacing everything on this truck with factory parts. 

If I'm going to spend that much time on a project, I want it to be a little more modern than the Renix system when I finish.

 

Are you fitting a GM reluctor onto the flywheel or plan to do a crank damper reluctor? I’ve made a few stand alone 4.0 harnesses from the 91-95 harness also. It’s a simple option if you prefer to go that route. I’m no fan of the renix or obd1 systems either. Considering the fact that these engines will run on a carb and hei, a 4.3 ecu should have no trouble running it. 

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9 minutes ago, ghetdjc320 said:

Are you fitting a GM reluctor onto the flywheel or plan to do a crank damper reluctor? I’ve made a few stand alone 4.0 harnesses from the 91-95 harness also. It’s a simple option if you prefer to go that route. I’m no fan of the renix or obd1 systems either. Considering the fact that these engines will run on a carb and hei, a 4.3 ecu should have no trouble running it. 

 

I'm doing a crank damper reluctor. I'm not exactly sure what I'm doing in the distributor yet. I've got my eye on a couple of options.

I've been running this truck on a HEI and the renix system for the last year. They run fine in batch mode.

But something else quit working and I decided this was enough of the renix system. Time for something newer.

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12 minutes ago, Thorwon said:

 

I'm doing a crank damper reluctor. I'm not exactly sure what I'm doing in the distributor yet. I've got my eye on a couple of options.

I've been running this truck on a HEI and the renix system for the last year. They run fine in batch mode.

But something else quit working and I decided this was enough of the renix system. Time for something newer.

Yeah Renix would basically guess the injection timing if it didn’t have a cam signal. Let us know how it goes and if you need any assistance. 

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50 minutes ago, Thorwon said:

I've been running this truck on a HEI and the renix system for the last year. They run fine in batch mode.

 

i have doing the exact opposite, running on LPG with the renix controlling the spark, and yes, batch mode in the 4.0 is like running a TBI system, the worse it can happen is that different cylinders get a slighty different amount of gasoline, at high rpm the system goes in batch mode anyway

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4 hours ago, zomeizter said:

kewl $#!& going on here, keep at it...

I got EFILive, 0411s are very tweakable and fast enough for some very cool mods...

I've got PCM Hammer for read/write of pcm and Tuner pro RT for tuning. They both work great.

If you haven't already, check them out.

 https://pcmhacking.net/forums/viewtopic.phpf=42&t=7579&sid=4e43ec79a693c10834bca5f8ff752b72https://www.tunerpro.net/downloadApp.htm

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  • 3 weeks later...

Well I've had to change up the distributor. When I installed it I didn't think about where in the crank rotation the sink signal was sent to the computer. I am getting a sink error.
I have no way to look at the signal so I'm guessing.
So I set the engine at TDC #1 and the reluctor was about 90 deg from the signal coil. I then rotated the distributor and reset the plug wires appropriately.
It idles much smoother and runs stronger.
This is a learning experience so I'm figuring it out as I go.
I guess I'm going to have to buy an oscilloscope. And then learn how to use it.

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