Project “Tomahawk”

[ghetdjc320]

[ghetdjc320]

Custom bracket made for the corvette throttle pedal since I’m runny a drive by wire setup. Also removed the pedal connection from the only brake booster and welded it to my 2001 XJ booster and replicated the factory 5 3/8 brake booster rod length. The stock 01 XJ booster will push your brake pedal out about another 1.25”. Mounted the booster using a trimmed piece of dynaliner along with 1/4 spacers. Sits perfectly with about 1/8” clearance to the pinch seam. Master cylinder and clutch mc also mounted up. Dash frame is in place as well. 
 

I have never seen an original black dash in this hood of shape. 
 

 

[ghetdjc320]

Electrical started. The ecu is going to be mounted in the old Renix location and the tcu (drive by wire controller) will go where the aw4 tranny controller is mounted on autos.

new bulkhead fuse block mounted.

 

 

[ghetdjc320]

LS ecu mounted in old Renix location. Has to be clocked pretty much in this exact position to not interfere with anything.

 

[Salvagedcircuit]

Looks awesome! If you are using a new booster, make sure to check if the booster push rod is adjusted properly to the master cylinder. I blindly trusted that cardone would set the new booster rod length to Jeep spec before shipment to match a WJ Jeep master. They did not. It wasted 2+months of my time. The booster rod was set all the way to shortest most recessed length.

 

Awesome progress as always! Thanks for all your input along the way too. I should hopefully be uploading my build log soon.

[ghetdjc320]

8 hours ago, commissioneranthony said:

Looks awesome! If you are using a new booster, make sure to check if the booster push rod is adjusted properly to the master cylinder. I blindly trusted that cardone would set the new booster rod length to Jeep spec before shipment to match a WJ Jeep master. They did not. It wasted 2+months of my time. The booster rod was set all the way to shortest most recessed length.

 

Awesome progress as always! Thanks for all your input along the way too. I should hopefully be uploading my build log soon.

Good reminder. Mine was set correctly for basically “zero lash” out of the box fortunately. I was really thinking of going hydroboost with this truck and may still in the near future. This build is going to slow down here for the next few months as work picks up and the weather is uncooperative 

[ghetdjc320]

Have to do some more alignment work but here are the basics. Door glass swap to the 97+ style and added power regulators.

 

[ghetdjc320]

Had to readjust the window regulator. Finished most of the door wiring. Just need to get the new latches in and grab a riveter to install the actuators.

The window works excellent now and the glass has almost zero play. Feels like a solid factory option now. Started on the chasis harness as well. Ignition, turn and dimmer switches all wires now. Decided to switch to the GM headlight switch since I needed a new switch anyways and the painless interface prefers GM components anyways. Working on getting all the wire routing taken care of which is really the majority of the work. Soaked the rubber accordion door wiring seals in diesel for a month and they are better than new. 

[ghetdjc320]

Electrical continues. Once I wrapped my head around a few tricky points (like the intermittent wiper wiring and cross cab wiring) it’s been pretty smooth sailing. It’s nice to have all these extra connectors in this kit to route wiring through the bulkhead connector. Keeps the firewall very clean. Not planning on running any specific relay center either. A few of the engine relays will be under the dash. Fan relays I’ll mount near the fans. Going to grab the arb compressor and route its wiring along with a small 4 channel amp wiring through the bulkhead connector. Had to add two wires and reroute some power from the painless bulkhead setup to power the wipers correctly. I didn’t want to delete the intermittent feature so I tracked down all the factory diagrams to get the wiring replicated. Also placed the correct vin tag on the dash and riveted it in place. Noticed that my wiper motor shaft was broken once I disassembled it! New one on order. Installed the door lock actuator on the drivers side and tested the window switches. All works great. Extremely easy to add keyless entry in these rigs in the passenger side of the cross cab harness. Contemplating any other electrical accessories I’d like to add into the harness. 

[Limeyjeeper]

Was the painless bulkhead connector a straight fit into the MJ bulkhead or did you have to modify the hole? It looks like a great solution that enables you to get rid of a bunch of crazy wiring in the OEM harness that is unnecessary. 

[ghetdjc320]

14 hours ago, Limeyjeeper said:

Was the painless bulkhead connector a straight fit into the MJ bulkhead or did you have to modify the hole? It looks like a great solution that enables you to get rid of a bunch of crazy wiring in the OEM harness that is unnecessary. 

It fits the same hole. You just need to drill out the mounting bolt holes a tiny bit. It has a huge amount of connection possibilities. One note though is that the fuse block is physically larger as it has more circuits than the stock one did. Even has power window and locks fused circuits built in. I really like the amount of customization it offers though. The ignition and turn signal switches are almost plug and play as is the dimmer switch. The wipers took quite a bit of work to incorporate the intermittent function. Some circuits are opposite of Jeep as well such as the washer motor circuit. The painless wiring provides ground but the jeep signal provided power through the turn signal switch. The wiring is the same either way as the motor just gets whatever you send down the line but the painless circuitry is a better design as it’s not flowing power through switches all over the place. 

[Limeyjeeper]

It looks like the number of wires you are dealing with is significantly smaller. The stock harness could be downsized by about 50% if the harness was logical. The number of splices, doubling back of wires and insane ground wiring creates an unbelievably inefficient harness, which makes this option very intriguing.

[ghetdjc320]

9 hours ago, Limeyjeeper said:

It looks like the number of wires you are dealing with is significantly smaller. The stock harness could be downsized by about 50% if the harness was logical. The number of splices, doubling back of wires and insane ground wiring creates an unbelievably inefficient harness, which makes this option very intriguing.

I agree. The factory wiring really needed a good modernization and some better fore thought. A bit of a challenge in the factory wiring is that they have integrated power train and chasis electrical at many points on the harness. Although I do have to interlace some wiring on this swap, it’s very little.

The stock Jeep VSS was 8k ppm so I’m running the Dakota sgt-100bt to modify that to the appropriate 128k ppm the ls pcm is looking for. Apparently I could also just reprogram the ls ecu to read the 8k ppm but it doesn’t give a smooth reading for cruise control with the drive by wire system. 
 

Also been adding all the wiring for extras. The dash switches will be something like: fog, compressor, front locker, rear locker, winch power and winch in and out. Also have heated seats, audio amp, aux USB ports, power mirrors, windows and locks, bed lighting and a bed mounted 12v outlet. 
 

Ended up scraping the idea of mounting the ecu under the dash. It fits but it would be a real pain to access for tuning. Mounted it and the DBW module to the drivers side inner fender. 

[ghetdjc320]

Most all the wiring has been routed now. Tail harness now includes a pair of 10am wires for a power outlet in the bed. The air locker line is also a part of the tail harness. 
 

For gauge senders, after consulting with Limey and reviewing the ls specs, the ecu needs to see ect but not oil pressure. The head on the drivers side already has the ect sensor for the pcm. I’ll be adding the Jeep gauge sensor to the passenger side using the appropriate metric to 1/8 npt adapter. I will replace the oil sender on the engine with the Jeep one. 

[Limeyjeeper]

2 hours ago, ghetdjc320 said:

I agree. The factory wiring really needed a good modernization and some better fore thought. A bit of a challenge in the factory wiring is that they have integrated power train and chasis electrical at many points on the harness. Although I do have to interlace some wiring on this swap, it’s very little.

The stock Jeep VSS was 8k ppm so I’m running the Dakota sgt-100bt to modify that to the appropriate 128k ppm the ls pcm is looking for. Apparently I could also just reprogram the ls ecu to read the 8k ppm but it doesn’t give a smooth reading for cruise control with the drive by wire system. 
 

Also been adding all the wiring for extras. The dash switches will be something like: fog, compressor, front locker, rear locker, winch power and winch in and out. Also have heated seats, audio amp, aux USB ports, power mirrors, windows and locks, bed lighting and a bed mounted 12v outlet. 
 

Ended up scraping the idea of mounting the ecu under the dash. It fits but it would be a real pain to access for tuning. Mounted it and the DBW module to the drivers side inner fender. 

The Jeep VSS transmits VSS signal using square wave DC. The GM PCM is looking for AC Sine wave so the GM PCM doesn't understand the Jeep VSS output, so setting the GM PCM to 8k won't help you. That is why you need the Dakota Digital box. It converts the Jeep VSS Signal from 8000k square wave DC to 8000k AC Sine wave. You need to use Application 2 (Spd, Out, L-L) with OUT 1 from the SGT-100BT to the PCM Pin 21 RED. The Jeep VSS Sensor Signal which goes to the Tach also needs to go to VSS input on the SGT-100BT box. Set the PCM VSS Pulses Per Rev to 3 and make sure the Pulses per Mile to 4000. That will make everything play nice. I forgot to set the PPR to 3 which is why my Cruise wasn't working. It is not a perfect speed match. At higher speeds it wanders by a couple of MPH but nothing serious.

[ghetdjc320]

[ghetdjc320]

15 minutes ago, Limeyjeeper said:

The Jeep VSS transmits VSS signal using square wave DC. The GM PCM is looking for AC Sine wave so the GM PCM doesn't understand the Jeep VSS output, so setting the GM PCM to 8k won't help you. That is why you need the Dakota Digital box. It converts the Jeep VSS Signal from 8000k square wave DC to 8000k AC Sine wave. You need to use Application 2 (Spd, Out, L-L) with OUT 1 from the SGT-100BT to the PCM Pin 21 RED. The Jeep VSS Sensor Signal which goes to the Tach also needs to go to VSS input on the SGT-100BT box. Set the PCM VSS Pulses Per Rev to 3 and make sure the Pulses per Mile to 4000. That will make everything play nice. I forgot to set the PPR to 3 which is why my Cruise wasn't working. It is not a perfect speed match. At higher speeds it wanders by a couple of MPH but nothing serious.

Good info! The sbt box says it will convert the 8k to 128k which is supposedly what the dbw wants. I was planning on splitting the speedo signal before it goes into the Dakota box. That way the speedo sees the stock Jeep sensor info like stock.
 

From what I gather, the stock vette system runs the vr (ac) vss at 128k ppm direct to the ecu then the ecu has a speedo gauge output at a much lower ppm (4K??). Looks like the tach signal also comes from the ecu to the tach in a stock setup. 
 

So @Limeyjeeper let me know if this sounds right: Jeep Hall effect 3 wire sensor out with the signal split between the Jeep speedometer and the Dakota digital unit input, then from the Dakota digital calibrated output to the high/low 2 wire ac input on the ecu. Tach out from the ecu to the Dakota box then calibrated tach signal out to the Jeep tachometer. 

I do love that the Dakota box provides a 5v sensor reference  power and ground that I can use with the newer style Jeep vss. Ultimately, the speedo gear will also have to be correct for the tire and gear ratio to provide the correct ppm readings for the speedo and ecu. Keep in mind that my wire colors are not stock for my LS harness. 

[Limeyjeeper]

10 minutes ago, ghetdjc320 said:

Good info! The sbt box says it will convert the 8k to 128k which is supposedly what the dbw wants. I was planning on splitting the speedo signal before it goes into the Dakota box. That way the speedo sees the stock Jeep sensor info like stock.
 

From what I gather, the stock vette system runs the vr (ac) vss at 128k ppm direct to the ecu then the ecu has a speedo gauge output at a much lower ppm (4K??). Looks like the tach signal also comes from the ecu to the tach in a stock setup. 
 

So @Limeyjeeper let me know if this sounds right: Jeep Hall effect 3 wire sensor out with the signal split between the Jeep speedometer and the Dakota digital unit input, then from the Dakota digital calibrated output to the high/low 2 wire ac input on the ecu. Tach out from the ecu to the Dakota box then calibrated tach signal out to the Jeep tachometer. 

I do love that the Dakota box provides a 5v sensor reference  power and ground that I can use with the newer style Jeep vss. Ultimately, the speedo gear will also have to be correct for the tire and gear ratio to provide the correct ppm readings for the speedo and ecu. Keep in mind that my wire colors are not stock for my LS harness. 

I totally misspoke in my previous post. It is the VSS signal that goes to the Speedo not Tach that needs to be split as you correctly state. So, your description is correct. If I remember correctly, I didn't run the tach back through the DD box just direct to the tach. I think the Tach will work fine using the output from the GM PCM Pin 10 Red.  Don't worry about the DBW it gets its signals from the GM PCM. As long as you feed speed correctly to the GM PCM it will manage the cruise control through the DBW box. It is the same as the cable Cruise that I have. It is totally managed by the PCM. As long as the PCM is seeing the correct speed from the VSS the cruise will be fine. I am going to check the tach tomorrow and confirm that I went from the GM PCM Pin 10 to the tach. I know I didn't go through the DD box. The only thing I use that for is to convert the speed signal.

[ghetdjc320]

53 minutes ago, Limeyjeeper said:

I totally misspoke in my previous post. It is the VSS signal that goes to the Speedo not Tach that needs to be split as you correctly state. So, your description is correct. If I remember correctly, I didn't run the tach back through the DD box just direct to the tach. I think the Tach will work fine using the output from the GM PCM Pin 10 Red.  Don't worry about the DBW it gets its signals from the GM PCM. As long as you feed speed correctly to the GM PCM it will manage the cruise control through the DBW box. It is the same as the cable Cruise that I have. It is totally managed by the PCM. As long as the PCM is seeing the correct speed from the VSS the cruise will be fine. I am going to check the tach tomorrow and confirm that I went from the GM PCM Pin 10 to the tach. I know I didn't go through the DD box. The only thing I use that for is to convert the speed signal.

That’s good to know! It would be great if the ecu tach output could run straight to the Jeep tach. I need to double check the wiring on the oil pressure gauge and confirm it doesn’t need to go to the LS ecu. 

[Limeyjeeper]

The 411 PCM (if that is what you are using) has no provision for oil pressure. It only has an oil pressure switch on/off provision which is Pin 70 Blue. That isn't needed to make anything run. I think that pin was only used in the Corvette tunes, it would kill the fuel pump if the PCM saw low oil pressure. I can also confirm I drive the Jeep Tach directly from Pin 10 Red on the 411 PCM. Hopefully yours will work too.

[ghetdjc320]

5 hours ago, Limeyjeeper said:

The 411 PCM (if that is what you are using) has no provision for oil pressure. It only has an oil pressure switch on/off provision which is Pin 70 Blue. That isn't needed to make anything run. I think that pin was only used in the Corvette tunes, it would kill the fuel pump if the PCM saw low oil pressure. I can also confirm I drive the Jeep Tach directly from Pin 10 Red on the 411 PCM. Hopefully yours will work too.

I wonder if that was the equivalent of an ASD circuit? If it’s not needed for anything I’ll just skip it. Awesome info on the tach. Thanks for your help

[Limeyjeeper]

6 minutes ago, ghetdjc320 said:

I wonder if that was the equivalent of an ASD circuit? If it’s not needed for anything I’ll just skip it. Awesome info on the tach. Thanks for your help

I think it for the Corvette owners who don't know what a dipstick is lol

[ghetdjc320]

47 minutes ago, Limeyjeeper said:

I think it for the Corvette owners who don't know what a dipstick is lol

[ghetdjc320]

While neck deep in electrical work, I’m staring to design the audio system as well. The stock speaker grills in the door heavily shroud the woofer and interfere with imaging tk a great degree. I don’t like the idea of an aftermarket speaker grill directly on the door panel but this much shrouding is just not going to work. I was planning to replace the lower carpeted portion of the door panel so the opportunity to have a clean fitting grill will be there. Plus I never really liked the carpet “pocket” on these door panels. I’ll delet that and add one of the later style plastic door pockets. I wonder the size of the Jensen accusound grills that came on the loaded XJs

[A-man930]

Very curious to see what you decide to do with the door speakers.  

Thank you for the detailed posts!