Converting from Chrysler to EZK ignition on your late model 240

I have decided to write this article after quite a few requests for the information and specific questions about the swap. I don't claim to be some professional electrical engineer. My reason for writing this is to help people sort through the information out there and get some solid answers and advice that works. I've done this swap five times and I've always been able to get the car running easily. There were a few websites in the past that described this whole process but the links have went dead. This should suffice to be a definitive guide to prepping your 240 ignition for a +T. I have intentionally left the image size of all scans large so that you can easily print them.

Let me say that I know there are different approaches to the ignition side of a 240. Some have reverted back to the K-Jetronic breakerless ignition system. Others have used more advanced systems such as EDIS and coil on plug with aftermarket EMS. With systems such as these readily available, some are asking me why to bother with this swap.

The answer varies, but I like it because its cheap, simple and reliable. For those not sure if your car has the Chrysler ignition; if it is a non-turbo 240 from 1982.5 through 1988 it should have a big module on the passenger side fender near the washer tank. That's the Chrysler box. Some came with a distributor that uses a Bosch cap, some come with a distributor that uses a a big white ugly cap. Doesn't make a difference, except you'll want to use the Bosch cap style that has a 3 prong connector right there on the side. More on this later, though.

For those not seeking huge amounts of power, this is an easy way to upgrade your ignition system to work with an F+T. Also, for those with dead Chrysler ignition system components, you can get a more solid NA system. If you are wondering what I mean, try monitoring a Chrysler ignition car timing with a light. You'll notice that it is shaky and bouncing around at idle. Next, check it on a car with EZK. Dead solid.

This conversion covers what will be needed to convert an LH 2.2 (85-88) car to EZK. Those with LH 1.0 and LH 2.0, I do not think this conversion will work. Principally because there is no provision (as far as I know) for a load signal from the LH for the EZK. If you have a car with one of the early systems, I recommend upgrading to LH2.2. Most of you are wanting to add turbos to your bricks and there are plenty of turbo ECU's and parts floating around for cheap.

OK, so now that I've convinced you that you can perform the conversion with ease, the first thing you'll need to do is get some parts. The first thing I recommend doing is checking the condition of your LH fuel harness. Good spark is half the equation, but if your fuel harness is rotted, then its not going to matter how good your spark is (if you determine that you need to replace your harness, just get one from a 240. I've found that the 700 series fuel harness becomes a big task to make fit in a 240.). Next, you'll want to pull an EZK harness and computer from a 700 series car at your local junkyard. For the harness, it does not matter if it the car is turbo or not. For the computer, it depends on what you need. I'm not going to spend a lot of time explaining this, because its pretty obvious how its done.

On a 700 series car you'll find the EZK control unit located on the drivers side of the car between the gas and brake pedal. It can actually be removed by removing one strategically located phillips head screw. Next, remove the harness. Clip all the zip ties that hold it under the dash. Cut all wires that arent from the EZK harness. There are a few that come out of the EZK harness that disappear into the underdash wiring. Those connect to the LH. Just cut them, we'll deal with them later. Next, once everything is loose from the inside of the car, pop the hood and pull the EZK connector through the firewall. There is about a 2" grommet that will come out with it making it easy to remove the whole connector. Next, remove the plastic shielding that holds the EZK harness and some other crap together. Feel free to cut and remove any wires that don't go to the EZK. Next, you'll want to disconnect and remove the power stage and connector, the knock sensor and connector and the hall sensor connector at the distributor. Free all these connectors from their locations. On the connector to the power stage, you'll have a few wires that can be cut. These will have to be changed later anyway. Once you've got all these connectors free, there is just some other random wires left in the insulation that holds them to the EZK harness. Cut the insulation and everything that isn't EZK related should fall out and can be trashed.
While you are here, go to your fuel computer (passenger footwell) and pull some extra pins out of the connector. The colors of the wire and whatnot are not important. Just be sure you can insert them into your harness later. Heres a tip; use a small precision flathead screwdriver to bend the tab that holds them into the connector.

Now that you've got your harness and control unit you can begin planning your install. One of the most common things I hear from people doing this conversion is that they "don't know how to make the LH and EZK talk to each other." The funny thing is that this is actually done by just four wires. One transmits RPM signal to the LH, one is a load signal from the LH to the EZK, a TPS signal that is shared by both and finally you have a knock enrichment from the EZK to the LH. You'll find that the wire the load signal is not existent in your 240 LH harness. This is why you grabbed a couple extra pins from the junkyard to install into your harness. Here are the functions of the EZK with the links between EZK and LH in red (taken from an old thread I started where 740ATL (Mike) posted them):

3. Supplies fault indication signal to test terminal (267) when diode connected
4. Supplies power to hall generator in distributor
6. Receives supply from battery across ignition switch
7. Grounded by throttle switch when throttle closed
8. Receives load from fuel system control unit
9. Receives 12V supply when thermostat (radiator fan thermostat) closes (B230FT only)
10. Grounds screen of lead from hall generator in distributor
12. Grounds screen of lead from knock sensor (228)
13. Receives signal from knock sensor
15. Transmits knock controlled fuel enrichment signal to fuel control unit (B230FT only) < Turbo ECU/ICU ONLY!
16. Transmits ignition pulses to power stage (419)
17. Transmits speed signal to fuel control unit
20. Grounds ignition control unit
24. Receives engine speed signal from hall generator.

And here's the diagram for that unit:

http://nickflyman.com/volvo stuff/ezkconversionpics/740-89-17.gif

You'll notice the three wires that go between the units are Y, Y/GR, and R/SB. You should easily find these connectors in your new harness (these are the ones that you cut from the dash-loom). Go ahead and replace your knock sensor with the one you got from the donor car. I usually just use a big set of vice-grips on the old one to remove it. Install the new one and be sure to aim the connector in an appropriate direction. Next, you'll want to mount your EZK. My favorite method is grabbing the bracket that the later model 240's used and putting it right on the firewall near the LH. This makes those three connections pretty easy and keeps things looking factory. Now, you'll want to use a holesaw or knockout tool to put a reasonable sized hole in your firewall for your harness. Use a grommet for all the wires so they don't become chaffed.
This is where you run into two different options for finishing this conversion. The first (and best, IMO) way of running your wiring is to remove all the Chrysler wiring (some of it runs underneath the crank pulley and is cracked and frayed anyway) and install your new harness along where the fuel harness already runs. Or, you could run the remaining wires (minus the knock sensor harness and powerstage) and hijack the Chrysler wiring. I think the pros and cons are obvious here, so I wont waste more time with that.
So now, you're going to want to look at this next photo and realize that your 240 fuel harness doesn't have a pin 24 in the ECU connector.

http://nickflyman.com/volvo stuff/ezkconversionpics/240lh.jpg

Use those spares you grabbed at the yard and insert them. At this point, you should be able to finish connecting everything between the LH and EZK. Go ahead and do that. IMPORTANT: If you are using turbo computers, connect the red/black wire from the EZK harness to pin 12 from the fuel computer. If you are not using turbo computers, leave it alone and don't connect the red/black to anything.
Now, if you are using your Chrysler ignition harness, I've provided the diagrams for the two flavors of Chrysler ignition.

http://nickflyman.com/volvo stuff/ezkconversionpics/earlychrys.jpg
http://nickflyman.com/volvo stuff/ezkconversionpics/laterchrys.jpg

Now that I've smacked you with some confusing wiring diagrams, let me walk you through it a little. You can use the orange, blue, small black, yellow, green, and the inner grey wire (you'll see what I mean, under the shielding) instead of removing this stuff and running wiring to the drivers side of the motor. Make sure these components are in good shape.
If you choose to rewire, go ahead and run the appropriate harnesses and wiring to the coil and distributor. In either case, you'll need to mount and connect your powerstage first. You are free to do this wherever the real estate exists. On 86+ cars, there's a nice little place for it in front of the battery on the drivers side fender where the later model cars came with EZK stock. You may need to extend wires though, I cant remember right now. There are two wires that you'll find coming out of the harness in your 240 near the coil. A blue wire and a red/white wire. The blue wire is your +12v that'll power up the entire ignition system. The red/white is your tach signal. Be sure these are connected to the coil. The blue wire will also carry power to the EZK unit.

I'm not going to go into detail on every single connection at the moment because I think that most of you are smart enough to figure things out and I'm pretty tired. I'm going to return to this and add more detail, plus a sort of FAQ/frequent issues section later. This should help people get an idea of what's involved in this swap and hopefully not be too afraid to try it for themselves. Feel free to email me any questions, corrections, or information I have not included.
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