OBD1 to Eagle wiring

[Nightpath]

Wrapping up the last bit for my swap. Anyone know of a OBD1 to Eagle dash wiring diagram, etc?

Chances are I'll be removing the stock firewall wire "block" behind the brake booster and putting the XJ one there in place.

I do have a spare dash with ALL the wiring (cut) so I can match it up before installing.

[eaglefreek]

Seems like a lot of work. Is there a reason you decided to go that route, instead of making the XJ harness a standalone harness which would only require a few wires to be connected to the Eagle harness. Not criticizing just curious.

[Nightpath]

How would I do that? This is my 1st swap to be honest. I want all the gauges to work properly...I'm learning

[rmick]

I have done this swap on my gremlin. There are only 5 wires that need to be tied into the jeep harness. The gauge wiring will still be the same with the water temp you may need to put a sensor in the back of the head there should be a plug in the head to remove and install your original sensor. The oil pressure will connect the same spot as your 258. The speedometer you will need  pass through adapter that will allow for the cable to connect and still have an electrical speed sensor if your running  the jeep auto transmission. Sorry I don't have the p/n handy for the adapter. Other wise there is just power ground and a couple of ignition switch on power to connect to the original wiring in the engine bay. If you want a check engine light you will have to add one from the jeep harness.

[eaglefreek]

Yes, pretty much what he ^ said. You'll need a wiring diagram and will have to weed out all the nonessential wiring from the Jeep harness. All you should be left to hook up to the Eagle would be a few power and ground wires, fuel pump and maybe a couple other miscellaneous wires. Since you are doing an AW4 swap at the same time you'll have a few extra to hook up like the NSS, brake sense for the TCU and reverse lights.

[DaemonForce]

I'm currently in the middle of figuring out the OBDII road to this conversion and I'm stuck on figuring out the CCD lines and what all to remove. I've gotten rid of a LOT so far. Still not sure if I'm going to keep the PDC but holy heck I like this massive +12v cable on the harness compared to the Eagle +12v. I might use this with an inline fuse.

[Nightpath]

That's why I went with obd1. Easier to wire.

That and I've come across jeeps that have had the engine pulled and the computer with it. Wouldn't start after installed. Ends up the security was bypassed (easy to do) but reset when the ecu was reset.

On a side note, snag the security system from a jeep (under the dash, accessed through the dash), install it. Start the jeep if you can now, run it a few minutes then while running disconnect the security system. Run the engine for a few minutes more.

Voila...ecu no longer recognize the security.

[DaemonForce]

It's not hard to wire, it's hard to UNwire. The PDC looks incredibly annoying being spliced and routed to infinity. Who did this? o.O

[Nightpath]

We figured that for the amount of changes that we are doing,it'll be easier to remove the Eagle wiring for the most part and put in the XJ wiring. From looking at it, alot of the wires are similar or the same. Anything that's different I can rewire to work.

Going to retrofit the XJ gauges to fit as well. I have a spare dash to use as a beta. By doing this I can just plug and play to bypass a lot of headache.

[captspillane]

Going to retrofit the XJ gauges to fit as well.

I took the 1992 style speedometer and trimmed it down to the shape of the Eagle Speedometer. Worked nicely and looks great in the original Eagle dash. Eventually I'll do one with the 1992 style steering column like you were planning too.

In the mean time I'm sticking with the Eagle gauges. It is easy to keep the wiring inside the cabin all Eagle and the wiring under the hood all XJ. For the speedometer use the Dodge Dakota VSS and your computer will have the VSS speed and your mechanical speedometer will have its cable, making the dash modifications unnecessary.

[captspillane]

I found the picture in my project thread. Apparently I had both the tachometer and the speedometer from the XJ in the Eagle dash.

Here are your options to change your speedometer. In newer fuel injected Jeeps the speedometer works off an electric speed sensor. On the Eagle it works mechanically.

I just found my new MPI (Multi Port Fuel Injection) speed sensor on the evil bay for 28.03 (buy it now, more than 10 available, free shipping). In comparision Autozone wants 70 dollars and Hesco wants 122. Helpful search terms to find what you want include the words "new" "speed" "sensor" "transmission" "vehicle" "Dodge" and "Dakota".

The same one was used on 88-93 Dodge Dakotas as well as 91 to 93 YJ's. The Speed Sensor has an input and an output. It screws into the CJ style transfer case adaptor that is also used in a 1992 XJ. The XJ speed sensor is nearly identical except that it doesn't have the threads and hole for the mechanical speedometer.

The first picture shows the YJ speed sensor I'm talking about. The second pic, in the middle, shows the 92 XJ version that does not have the hole or threads in the center (to be honest it shows a Dodge speed sensor that’s nearly identical). Later XJ’s replaced this two piece design with a one piece electronic only design. The fourth picture shows the entire two piece design that gets installed into your transfer case.

Option 1: Mount it directly on the back of your Speedo using a brass adaptor to go from tiny threads to big threads. It’s tight but this keeps everything else stock. “Tougeagle” used this method in his popular write-up.

Option 2: Mount it on the firewall, have original speedo cable go to it, then an International Scout upper speedometer cable which is only about 2 feet long go from that to your speedo cluster. Scouts had some doohicky on the firewall that interrupted the speedo cable just like this does.

Option 3: Get a common 92 XJ adaptor that plugs into the side of the transfer case. You'll need that piece from a junkyard. Thread this 91 YJ speed sensor into it. Get a 91 YJ mechanical speedo cable (threaded at both ends) to go from your dash to the speed sensor on your transfer case.

Option 4: Combine option 2 and 3. This is my choice and my recommendation. You use a YJ mechanical speedometer cable instead of the original Eagle Speedometer cable. Screw one end of the speedo cable directly into the XJ transfer case adaptor and the other end into the speed sensor mounted in a convenient spot under the hood. I’ll have the short Scout cable to go from the speed sensor to my dash. This keeps all electronic junk organized inside the hood.

Option 5: Eliminate the mechanical speedometer totally by modifying an XJ speedo to fit into the Eagle dash. I included a picture of the dash I’m making for my main car with an XJ tachometer and Speedo.

The last three options are the best in my opinion because you can just unscrew the speedo cable and leave the transfer case fluid alone if you’re just removing the transmission to work on something else. It’s a mess to deal with popping that stupid integrated speedo cable out of the transfer case all the time. All Jeep transfer cases are interchangeable if you upgrade later, so you’ll only have to buy these parts once.

The last picture shows a 242 transfer case. The threads are visible along the slip yoke housing. That's where you'll find the internal adaptor you need from a junkyard. The speed sensor that screws into it and the different size gears are all available new. All early XJ's had these but eventually they went to the one piece electronic only design. A CJ Dana 300 piece is supposed to be the same, but I haven't confirmed this. I just know all the new process transfer cases are interchangeable speedometer adaptors.

[Nightpath]

What did you do with the fuel gauge, temp, oil and all that?

I'd love to wire my OBD1 gauges into the Eagle cluster by just moving the pieces over