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Supercharged LS3 crammed into an XJ
- Thread starter Skruffy
- Start date
I spent all weekend chasing down the source of my gauges not working problem. I read all the threads, tried every trick, cleaned every pin and checked every ground, and to no avail! Anybody know of any experts in CCD bus or XJ wiring in general? Extra points if they are in the San Diego area.
Scrubber3
NAXJA Forum User
- Location
- North Carolina
https://www.lsxmag.com/tech-stories...-on-obdii-vehicles-with-the-edge-insight-cts/
Look for one of these. It'll solve your problem and you can ditch the unreliable Chrysler IPC.
The spot behind the bumper is the location for the intercooler on the 2.5L turbo diesel XJ. It can be an out-of-sight, out-of-mind mud trap depending on where you go wheeling.
I have often wondered if it would be better to use an air to water intercooler. This could be done using a separate cooling system to the engine, an electric coolant pump and radiator(s) with fan(s) located in the rear quarter(s) with the intercooler closer to the compressor output.
The Toyota Celica GT-Four RC was a homologation model used for compliance with FIA World Rally Championship rules. It used air to water intercooler which Toyota considered better for competition use than air-to-air intercooler in the normal GT-Four.
Good info. Thank you for insight. The camaro had a liquid to air intercooler that was entirely independent of the engine coolant system just as you described although it was placed in the very fron of the vehicle so no fan was needed. I kept the reservoir and pump wiring harness and hoses for use with this project. The radiator itself is way too big to fit anywhere up front on the jeep. Since I wont be flogging the jeep too terribly hard (at least not often) I think that the space behind the bumper will be my best bet. Many folks that only boost 6psi dont even bother with an intercooler so I am inclined to believe that I can get away with a small one in that location. I called Magnuson (the supercharger manufacturer) and they strongly recommend running some sort of intercooler. I will have to keep the mud in mind and remember to rinse it out after any exposure.
Scrubber3
NAXJA Forum User
- Location
- North Carolina
Maybe install it on top of the engine and run a scoop on the hood like the older Subaru STI? Just thinking outside of the box and throwing it out there...
I was able to solve my gauge problem. I am happy cause I was able to fix it but also a bit embarrassed to report that the problem was me getting greedy with the deletion of the XJ harness and removing the 12V power supply to the XJ computer.
If any of you guys are gonna mess with your XJ harness PM me and I can go over some key points about what not to touch!
- Location
- In a strange land
Glad to hear you found it.
So many problems come down to such simple details. The challenge is figuring out just which simple detail it is.
So many problems come down to such simple details. The challenge is figuring out just which simple detail it is.
old_man
NAXJA Forum User
- Location
- Loveland, Colorado
Cool Project.
Thanks Old Man. Not as cool as your tear drop trailer, that is some championship fabrication. Love the custom hitch.
Should be getting my driveshafts back tomorrow which means I will be taking him for a spin around the block in the afternoon. Super excited.
Got a couple electrical gremlins to chase down but nothing that will cause problems. Speedo and tach not working yet. And for an unfathomable reason I get a no bus error after about fifteen seconds of having the climate control in any position besides off! This one is a mystery but likely if from the AC circuit since it is the only one that was interrupted.
I topped off and burped the coolant.
I ordered two 11”x6” heat exchangers for the inter cooler. I am going to mount them in series behind the bumper. I couldn’t find anything that would fit behind the grill or anything that would fit across the whole bumper space and couldn’t think of a reason that they wouldn’t work in series so we will see what happens. Going to try to get it into an exhaust shop Monday if the California COVID madness doesn’t shut them down too.
I will also need to find a tighter elbow for my intake but it won’t really matter until I have the hood sorted out.
Got a couple electrical gremlins to chase down but nothing that will cause problems. Speedo and tach not working yet. And for an unfathomable reason I get a no bus error after about fifteen seconds of having the climate control in any position besides off! This one is a mystery but likely if from the AC circuit since it is the only one that was interrupted.
I topped off and burped the coolant.
I ordered two 11”x6” heat exchangers for the inter cooler. I am going to mount them in series behind the bumper. I couldn’t find anything that would fit behind the grill or anything that would fit across the whole bumper space and couldn’t think of a reason that they wouldn’t work in series so we will see what happens. Going to try to get it into an exhaust shop Monday if the California COVID madness doesn’t shut them down too.
I will also need to find a tighter elbow for my intake but it won’t really matter until I have the hood sorted out.
Figured out the problem with the speedo: when I rebuilt the transfer case I installed the VSS in the incorrect orientation. I had it setup for a smaller gear. Got her swapped and speedo jumped back to life. Only one electrical gremlin left. The dreaded and mysterious no bus error.
That sounds like a terminating resistor might be missing? What all was removed from the bus?
I did a very good circuit diagram study to identify what I changed that would have caused this. When I wired the AC circuit (into the GM ECU) I used the existing XJ HI and LO pressure sensors and connectors. I gave myself 12V from behind the dash area, ran that to a button, that went through the firewall and to the LO pressure switch. Here is where I cut the Blue/White AC sense wire to apply my 12V to the XJ circuit (LO pressure sensor connector) when my dash AC button is pressed. The current then flows to the HI pressure circuit, if that sensor is in limits it closes the switch and sends current to the GM ECU. The GM ECU sees this, turns on the radiator fans and sends current to the AC compressor clutch.
The problem was that the XJ ECU was looking for voltage on that Blue/White AC sense wire. I very timidly gave it 12V from another source turned the AC on and crossed my fingers. I waited the requisite 15-20 seconds and much to my delight no more no bus error!
When I highjacked that circuit I didn't realize that it would cause me any problems and still don't see how that ends up being a no bus errors since none of that circuit is on the bus.
I am sure there is a way to use the XJ circuit but it cuts power instead of providing it at that sensor switch so I just couldn't figure it out. The folks at Novak tell me that a few people have been able to make it work as well.
I also just got my driveshafts back but the chuckleheads that did the work for me lost half of the hardware so I need to get those in the morning. After that I will bolt them in and take Skruffy for a quick flog around the block. See if I cant brake something on the first try!
If you wig out one of the modules on the bus it can pull the bus hi or lo and not release it and it prevents the other modules from talking to each other and it throws the code. They weren't very smart back then.
I agree. Would love to see a video of this thing running.
Once I get the exhaust done I will be able to drive it on the street without fear of a life sentence from the California air resources board. Then I can get you guys some video of it. I guess I will put it on YouTube and link to it from here. Unless some of you know how to post videos on here. I have been using Tapatalk and it will not allow videos.
For reasons that I can not explain my tachometer started working yesterday. It has been dead the whole time. I ran the GM crank and cam position sensor data into a module from Novak that translates it into Jeep then feeds the XJ ecu and eventually the tach in the dash. It has not been working and I couldn’t figure out why. I did all the troubleshooting, checked all my wires, called Novak and even talked to the inventor of the device. He supposed it was a defective module and sent me a new one. Well, yesterday after a blip on the throttle I actually saw the tach come to life. Makes no sense at all. But now it works just fine. I guess like many things it just needed a little motivation to get moving. When the new one arrives I will send it back and try to talk with the inventor again to see if he has any idea why this would have happened.
For reasons that I can not explain my tachometer started working yesterday. It has been dead the whole time. I ran the GM crank and cam position sensor data into a module from Novak that translates it into Jeep then feeds the XJ ecu and eventually the tach in the dash. It has not been working and I couldn’t figure out why. I did all the troubleshooting, checked all my wires, called Novak and even talked to the inventor of the device. He supposed it was a defective module and sent me a new one. Well, yesterday after a blip on the throttle I actually saw the tach come to life. Makes no sense at all. But now it works just fine. I guess like many things it just needed a little motivation to get moving. When the new one arrives I will send it back and try to talk with the inventor again to see if he has any idea why this would have happened.
