ghetdjc320 Posted March 2 Author Share Posted March 2 2 minutes ago, Limeyjeeper said: I used the AC request from the Jeep HVAC controls into the 411 PCM. It will then handle the idle and fans for you. The tach output worked fine using the output from the GM 411 PCM Pin 10 Red. Set the Tach output in the PCM to 12v pullup. No pull up resister needed. I never managed to get the speed into the PCM to work accurately even with the Dakota Digital box. Not that I needed it because I am running a manual, it does cause issues for the Cruise Control. It will be a spring job to finally figure that out. The CC ran for a while, when I first did the build but not now. Need to go back to basics. Good to know. Do you happen to recall what pin you sent the AC request to on the pcm? For vss, I’m using a Dakota digital 128k sender that I modified to fit the Jeep sender. So the ecu will see 128k ppm just like the stock t56 put out. Then using the Speedo output from the pcm which is supposed to be 8k ppm just like stock Jeep. I have the Dakota digital box if needed to convert frequencies but I’m hoping it won’t be used. Link to comment Share on other sites More sharing options...
Limeyjeeper Posted March 2 Share Posted March 2 Should be pin 17 on the red connector. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 2 Author Share Posted March 2 23 minutes ago, Limeyjeeper said: Should be pin 17 on the red connector. Sounds good, that’s what I got. Apparently on the corvette programming, the ac request on pin 17 is a ground request. Painless and psi both advised using a 12+ but that appears to only apply to truck and f body programming. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 2 Author Share Posted March 2 Coming along…. I am really liking how clean the wiring is when routing it all behind the engine. This has taken a painstaking amount of planning and routing, making sure no circuits are missed. There are many connections that need to be added to the painless harness but ultimately it seems to be a good solution for replacing all the factory wiring. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 3 Author Share Posted March 3 Following up on the TSB posted before, it appears that this TSB came out in 2003 and the 2004 and later valley covers remedied this by raising the little flange on the top of the valley cover a bit higher to prevent water intrusion. I just check my new valley cover and sure enough it has a more pronounced "ridge" than the original. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 6 Author Share Posted March 6 So, I've decided to do a little writeup on the Jeep A/C system and how it pertains to an LS swap, particularly a C5 corvette LS1/6 swap. For a little back history, The Jeep HVAC control deck sends a signal to the ecu known as A/C select. The Jeep ECU then receives a signal on another terminal that is routed through the A/C pressure switch and the evaporator thermal sensor known as A/C request. The ECU may have some logic processors that will account for such things as engine coolant temp or other criteria before it triggers the A/C clutch relay, but it doesn't account for much. Now onto the LS side of things. The 411 PCM had many different programs that could be flashed to it. The C5 corvette programming had two versions of AC control. One was called "manual" and the other "automatic". This has to do with the climate controls or HVAC deck. For the version that had "automatic" controls, there is a serial data line that goes into the PCM that contains some of the HVAC control deck logic functions. The "manual" AC systems had an "A/C request" signal that goes to pin 17 on the red connector. This was a 12v- or ground connection. It is noteworthy that this is not the same programming as the F body cars or any of the trucks as those mostly had a 12v+ signal on this pin. It can get to be annoying and confusing when people refer to "ls" engines and "411" PCMs as if they were all the same for Gen 3 engines. Most references I see from wiring harness manufacturers and aftermarket PCM tuners are using and referring to f body or Camaro programming on the PCM. Back to the C5 corvette programming on the 411 PCM; In regard to the AC system, the corvette uses a 5v A/C pressure sensor with a female M10 sensor port that goes on the high-pressure side of the system (between the drier and expansion valve high side for most Jeep applications). The GM PCM receives the ac request ground signal, checks the ac pressure signal and integrates all of the logic algorithms such as engine coolant temp, throttle position, RPM, engine load (MAP), and vehicle speed to determine when the compressor will be triggered and when fans 1 and 2 will run (on a Jeep triple fan setup, Novak recommends running the driver's side and center radiator fan as "fan 1" and the passenger side radiator fan as "fan 2"). The PCM also receives confirmation that the A/C clutch has received an activation signal by sensing voltage on pin 18. I've attached a diagram below of the way this is all wired. I have thoroughly subscribed to the guidance Novak has provided to "make the engine think it's still in its original application" to the extent possible. I'll post up how I will be wiring my system shortly but i'll be following the GM layout as much as practically possible. Note the diagrams for the ac system and the connector view for the ac pressure sensor Air Conditioning - Compressor Circuit 2002 C5.pdf Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 9 Author Share Posted March 9 Pure wiring madness. Took a break from electrical and started assembly of the rear bumper. I wanted the diy version as I wanted to do a few mods to it for a cleaner look. Here is a glimpse of my exhaust system as well. Lots of meticulous parts selection and test fitting. The cats are stainless spun vs ceramic core. Link to comment Share on other sites More sharing options...
Tsalagi Posted March 10 Share Posted March 10 Oh the patience you must have! Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 12 Author Share Posted March 12 Under hood wiring is now complete with all circuit installed and tested. Everything works excellent. onto the interior side now. Also with the unneeded tabs removed from the np242, I was able to keep the SFR tcase skid/crossmember tucked up neatly. There is exactly a 1/4” gap between them Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 12 Author Share Posted March 12 Added the correct wiring for pcm control of the ac system. Should be a factory like integration now utilizing the GM pressure sensor. The trinary switch has been eliminated. Will still be using the oe freeze switch for the evaporator core as well. Also swapped over the correct 38 tooth Speedo drive gear so the pcm will read the correct speed which is relayed through the Dakota digital 128k ppm sender. The 4k ppm output from the GM PCM will be sampled and up converted to 8k to run the 120mph Jeep speedo through a Dakota digital signal processor Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 13 Author Share Posted March 13 Tidbit of tech info for posterity: the Tom woods np242 sye kit shift rail plug thread size is 5/8-18 and approx 1/2” long. This is also a common automotive oil pan plug size. This also fits the switch port on the NP242. Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 14 Author Share Posted March 14 Well, what a day with wiring. Couldn’t figure out what was going on with my power to the pcm. When the key was off the pcm ignition was on but went off when the key was on. Turns out painless wired the relays all wrong and stuck the ign power on the N/C side of the relays. Took several hours to rewire but I’m happy to report that it’s working perfectly now. Was able to test engine circuits now and they are working great. There has been countless mods along the way such as wiring in a normally closed relay into the brake circuit to provide the pcm with the necessary signal to deactivate the cruise control. Also wired in the Dakota digital signal converter and set it up to provide the 8k ppm signal for the jeep speedo. I gave the pcm the correct 128k ppm signal along with the appropriate speedo gear for the ratio and tire size. I’ll calibrate the pcm further if needed so it sees the exact speed along with the speedometer. All the wiring, PCM and TAC module fit under the dash using the modified renix ecu bracket though it is a painstaking process. Was also able to mock up the air intake and it’s a perfect fit. I used a 4”-3.5” bending reducer, genuine carbon fiber tubing then a 30* coupler which I shortened then the maf/oat and filter. The errant relay system ridiculousness Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 19 Author Share Posted March 19 Some brief updates: added a clutch switch that will act as both a starter safety and a clutch signal to the ls pcm for fuel and spark table triggers. The switch I found from my local oreiolys was for a Hyundai Elantra of all things. I’m sure it fits multiple years but I went with 2006. The switch has a normally open and a normally closed set of contacts. The normally open will be for the starter so the circuit will close when pressing the clutch. The other set of contacts is what the ls PCM is looking for and opens the circuit when the clutch is pressed. Fabbed up a little bracket with some 16awg sheet and bolted it to the clutch pedal bracket. Added a small stack of washers as shims to set the proper switch depth. Works very nicely. The jeep is headed down to the exhaust shop tomorrow so I finished installing the front and rear driveshafts and dialed in the front suspension. Also fit up the rear bumper just so they can see what brackets will be on the frame. You can see how I modded this bumper. I cutout some 3/16 plate and welded shut the bumper lights and the various accessory bolt holes they drill into these. All in all I guess this is currently the best option now that JCR isn’t producing the rear bumper anymore. I do like how this turned out (still have some additional welding and grinding to do) but it was a lot more work. I set my upper and lower control arms as well. Lowers are at 16” plus a 1/8” shim in the control arm adjuster in the frame side. Uppers are set to 15” eye to eye. That gave me a caster of 10* which is quite nice. I do like how you can get these nice specs with these lower lifts. Link to comment Share on other sites More sharing options...
Comanche SS Posted March 19 Share Posted March 19 Looking good, what’s the plan/intention with the exhaust? Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 19 Author Share Posted March 19 1 minute ago, Comanche SS said: Looking good, what’s the plan/intention with the exhaust? Dual 2.5 is the plan. Picked up a borla dual in/out muffler with internal x pipe, a pair of stainless spun cats and some o2 bungs with heat sinks. Once exhaust is wrapped up I’ll do the final touches on electrical to get the engine running. Link to comment Share on other sites More sharing options...
Comanche SS Posted March 19 Share Posted March 19 52 minutes ago, ghetdjc320 said: Dual 2.5 is the plan. Picked up a borla dual in/out muffler with internal x pipe, a pair of stainless spun cats and some o2 bungs with heat sinks. Once exhaust is wrapped up I’ll do the final touches on electrical to get the engine running. Nice, should be pretty good. Plan to run both 2.5” pipes on the passenger side of the transfer case? Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 19 Author Share Posted March 19 Just now, Comanche SS said: Nice, should be pretty good. Plan to run both 2.5” pipes on the passenger side of the transfer case? I believe so. Will scope it out with the shop and see what can be done. With the x pipe, I'm not terribly concerned about keeping things equal length. Link to comment Share on other sites More sharing options...
Comanche SS Posted March 19 Share Posted March 19 1 minute ago, ghetdjc320 said: I believe so. Will scope it out with the shop and see what can be done. With the x pipe, I'm not terribly concerned about keeping things equal length. Yeah…Hopefully its a little quieter than mine, a single 3.5’’ system lets it breathe but it sure isn’t daily driver friendly, but then again nothing about my build is lol Link to comment Share on other sites More sharing options...
ghetdjc320 Posted March 19 Author Share Posted March 19 Future post hold Link to comment Share on other sites More sharing options...
ghetdjc320 Posted Friday at 03:01 PM Author Share Posted Friday at 03:01 PM And here we have it, true dual exhaust on an MJ. Once I get the engine running and the truck driving, I’ll have the exhaust shop tuck the tips up a bit closer to the bumper and trim them flush. Also would like to get some extra clearance near the pumpkin. Definitely some challenges working with an LCG engine swapped rig. But overall very satisfied with the results. Looking forward to hearing it for the first time, hopefully over the weekend. Link to comment Share on other sites More sharing options...
Comanche SS Posted Friday at 03:33 PM Share Posted Friday at 03:33 PM They tucked it up pretty nice near the trans, I’m impressed. Excited for your truck to come to life, I May have to stop by! Link to comment Share on other sites More sharing options...
ghetdjc320 Posted Friday at 04:07 PM Author Share Posted Friday at 04:07 PM 34 minutes ago, Comanche SS said: They tucked it up pretty nice near the trans, I’m impressed. Excited for your truck to come to life, I May have to stop by! By all means! Planning on getting it fired up over the weekend. Then it's on to finishing up the brakes and cab wiring with is about 80 percent complete so far. I think I think the end is finally in sight. Curious to see what curve ball this thing throws at me next Link to comment Share on other sites More sharing options...
ghetdjc320 Posted Friday at 05:09 PM Author Share Posted Friday at 05:09 PM Another project I'm going to knock out: I noticed a bit of play in the steering column and discovered its the 4 external torx bolts that hold the tilt head onto the column. You can sort of get to two of them to tighten them but two remain inaccessible unless you remove the two pivot pins and the tilt head. Ordered up the remover tool and will pull those out to Loctite them and re-secure everything. Also had a bit of slop in the OE steering shaft u joint so i picked up a Borgeson HD unit to replace it. Will report back on how it all fits. Link to comment Share on other sites More sharing options...
A-man930 Posted Friday at 05:27 PM Share Posted Friday at 05:27 PM Column work is such a treat Link to comment Share on other sites More sharing options...
watchamakalit Posted Friday at 06:07 PM Share Posted Friday at 06:07 PM Tightening those bolts is not that bad. I'm sure it's well within the scope of your abilities. Surprised to see what appears to be a steel exhaust not of the stainless variety. You getting cheap at the end of the build? Lol Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now