[HOWTO] 1997 Protege 1.5L (Z5) HEI mod

[Spudz76]

If you're like me, you hate the integrated "all-in-one" distributor on the Z5 engine, because if any single component breaks (ignitor, coil, etc) you have to replace the entire unit. I just got my 97 Protege and it has a "runs fine, until it doesn't run at all" problem, and it will cut out at any time, so I suspected the ignitor. After a whole bunch of research, reading about the HEI mod on Probes and other KL's, and attempting to adapt that to the Z5, I've successfully got it running off an HEI module - and the following is a brief overview of the steps involved.

1. Remove the distributor (two 14 mm bolts in the side of the head hold it in, make reference marks etc for timing so you can put it back in exactly how it came out, you might need a new O-ring but mine happened to be fine)
2. At the bench, remove the cap, rotor, and shield/cover from the top. Pay attention to how they came apart, etc. Most of this only fits one way but it's a time saver if you don't have to try all 3 positions for the rotor until it goes all the way on, etc.
3. Look down under the ignition reluctor (the only thing left on the top side of the shaft, with four fingers pointing down which pass the timing sensor gate to trigger the ignitor) and find two screws next to each other with metal straps running to each side. These are the internal coil + and - terminals, and unlike the KL HEI mod these are not available outside of the distributor assembly (believe me, I hunted for them).
4. Assemble two wires with a ring terminal the size that will fit these screws on one end, and a female spade connector on the other end. These will be the ones you connect to the HEI module "B" and "C" terminals, and since it's the main power for the coil they need to be at least 16 gauge. I personally would not skip soldering these at both ends, and heat-shrink at least two or three layers over each end (you never want this to short out, and it gets hot in the area, so regular electrical tape is probably a bad move). I also color-coded mine with red and black for + and - because you need to know which is which later on.
5. Remove the coil terminal screws, I was able to do this with a small precision philips screwdriver even though you have to get them from an angle because the reluctor hat is sort of in the way. They are somewhat tight so you may need to clap a vice grip on the screwdriver to get some torque, be sure to press down and don't let the screwdriver slip out of the screw head.
6. With a drill, make holes in the side of the distributor in the region immediately between and nearest the terminals. Be sure to stay above the little seam line as there is solid metal behind the plastic below that point, and you only want to drill the plastic, clear of everything. On mine, I used a larger bit than was probably needed and ended up with a larger gap broken out of the side. The point of this is to be able to screw the eyelets flatly on the terminals and have them come directly out the side of the distributor housing without interfering with any moving parts (remember this thing spins really fast) and also be sure not to short any connections (you used lots of heat-shrink right?)
7. Orient yourself so that the distributor is the way it is when it's installed on the engine, and the coil terminals will be vertical towards the back. The top one is + and the bottom one is - so install your wires by slipping the eyelet over the hole and reinstall the screws. Make sure nothing interferes and everything is clear. I chose to pick the coil straps up a little and slip my eyelets in between the strap and the base where the screw goes, but it will work however you accomplish the connection. Tighten the screws down to at least as tight as they were when you removed them, if not an 1/8 turn more.
   
8. Reassemble the cover/rotor/cap. Be sure the rotor is on properly, it should go on all the way and the bottom edge of its hub should be almost touching the shield/cover thing. If it doesn't push on all the way try one of the other two positions (the shaft is a triangle and one side is a bit different than the other two, so it will partially go on in the two 'wrong' positions and only all the way on in the proper one)
9. Reinstall distributor on the engine using the marks you made as your original timing depends on this being put back and twisted exactly to the same point before tightening down the bolts. Quadruple check. Then check again. You will have to fiddle with it until the cross piece drops properly in to the seat in the front cam, if it does not slip in with near zero force then keep fiddling until it does (DO NOT FORCE IT).
10. Now, go find a HEI module howto from a KL and hook the HEI module up as detailed there (ground the "W" pin AND the mounting screws of the module, connect the coil "+" to "B" and "-" to "C" same as they do, using the wires you just added instead of the two wires from their extra three-pin connector that we don't have)
11. The final magic is to connect the "G" pin on the HEI module to the spark trigger signal from the computer. Through trial and error I located mine, it is the third wire counting from the rear of the connector (as installed on the engine), and mine was yellow with a black stripe (this could be different on other years I guess, that still use the Z5 Mitsubishi distributor, with the seven-pin single connector on top, but the position will not be different.) Cut this wire and add a length of wire that will reach your desired HEI module position to the harness side. The connector side, on the distributor, only feeds the stock ignitor which is either dead or soon will be, and since we can't easily remove it, it has to be disconnected so that it isn't interfering with the HEI module driving the coil.
12. Reconnect everything else (plug wires, etc) and fire it up, enjoy!

Of course you can also continue on and do a full external coil setup (MSD or stock external HEI coil) but that requires modification to your cap, and needs to be modified again every time you change caps (tune-up time). The methods are similar to the KL HEI mod howtos, basically hook up a plug tower to the strap that normally goes to the stock coil "spike", or if you can't locate one of those (MSD seems to no longer make the right one) you can modify a coil wire and connect it directly. If you don't want to drill the distributor to access the stock coil terminals, you can just skip that part and go external coil from the beginning - but in my case it seemed easier to drill a couple holes and hook up low-voltage wires than to drill a cap and install high-voltage connections, and there is nothing wrong with the stock coil (it's pretty powerful) as long as it's not failing.

Benefits of this mod include being able to get another module for $20 from any old parts store anywhere (as opposed to an entire distributor) in case it ever goes bad again; possibly a better spark (these modules can drive 5 amps, I don't know about the stock ignitor - and the same module is used on V8's so they can easily handle a 4 cylinder to any RPM); and remotely mounting this module on a good heat sink away from the engine beats the stock ignitor and how it is mounted to the distributor body which gets heated by direct contact with the head, so it's always toasty and that shortens the life of electronics which is the main reason the stock ignitor likes to quit working in the first place.

[Spudz76]

Got a used distributor from the local yard, stuffed it in and still does exactly the same thing. Currently completing an external coil mod and will take some pictures of things this time.

[kertap]

Pics!haha

[Spudz76]

I think it should be visible now - not sure why the attachment_id changed

[Spudz76]

I need to revise the original post, as I've learned just about everything anyone would want to know about how the Z5 ignition actually works, and the best way to set up an external coil and ignitor (ignition module).

I took my original distributor (I've collected 3, all of them no longer are reliable) and stripped it down. This just requires the cap/rotor/shield removed, and then the screw inside the top rotor mounting triangle (top end of the shaft) removed, the entire upper assembly comes off the top - don't lose any parts, but they only fit back on one way so no worries about making alignment marks. Remove any screws you can get to now on the "guts plate" which holds the cam position pickup, original ignitor (the little black square thing with three legs), and the 1000ohm tach resistor. Then that should lift off the top exposing the original coil. Same deal, any screws you can see with the guts plate removed, and then the coil should lift off.

Now on the guts plate, I snipped the three legs of the original ignitor and pried it out of there, and snipped the coil hookup straps, this is because we won't be using either of those parts again, and all of our ignition wiring will be external. Reinstalled the guts plate onto the two corner 'towers' leaving the coil in my junk pile. Use the cap screws as those are what normally go in those holes. Place the washer, the trigger wheel (reluctor), and the rotor mounting triangle back onto the shaft, note the flat-sided keyway shape on the parts and like then up to fit, it should be straight and secure and easily held in place while you get the hold-down screw back in the end of the shaft. At this point the guts plate and the pickup may be misaligned a little due to the coil being gone (it used to mount to the coil, not just to the cap hold-down ears) - I didn't worry about this and as I assembled the dust shield, rotor, and modified "tower" cap I left the cap screws just a touch loose and fine tuned it so that when I spun the shaft the reluctor wasn't rubbing or making any "ringing" sounds as both of those are signs it is not at the proper clearance - which is "fits through the slot in the pickup without rubbing" there really isn't a clearance like with the crank sensor. Anyway, once this is all back together you have a purely mechanical spark distribution device stripped of all its other functions attached to a cam position sensor. UNLIKE the usual ignition, this reluctor is NOT an ignition reluctor, which is where some of my assumptions went wrong. This reluctor has one "finger" just a little wider than the others which is how the PCM syncs up with the cam position. Then once the PCM has processed this signal, it generates a related signal back to the ignition which replaces the usual physical ignition reluctor signal. So this ignition setup is "reluctorless" even though there is a reluctor for the CPS (mind blown).

That brings me to my next issue, which is that the stock coil power sources are not good enough for the TFI/HEI e-core type coil, and debatably good enough for the stock coil. Your main coil power comes in through that tiny 16 or 18 gauge wire on the top connector - most coil wires on other cars are at least a 12 or 14. Also, the same power rail that supplies the coil also powers up your oxygen sensor preheaters and some other things, so we're jumping off of that bus and feeding the external coil and module direct key-on voltage from the engine distribution box. I don't have ABS so I used that position, it already has the blades there just no fuse and no wire hooked up below. It was easy to pull the box off its mount and twist it over to get a wire hooked up (you need a female spade disconnect of whatever size will fit the fuse blade on the top-side), just run that directly to your coil+ and the "B" pin of the HEI module. Then I also avoided the internal resistor for the tach line by snipping the white wire (second from the rear on the 7-pin top distributor connector), soldering a 1000ohm resistor inline and hooking that directly to the coil- (and "C" pin of the module). This only feeds the diag tach connector and the cluster, and the resistor is there to limit current (so an error in the ignition won't fry your tach).

So now the entire ignition triggering setup is fully external (including not using the original power source), all that is connected to it are the white wire via resistor, and the yellow/green wire which is our trigger back from the PCM, power from any circuit available in 'run' and 'start' (note some accessory feeds are shut down during starting, and will give you problems, therefore I used the ABS) and ground of our own as well. The only signal on the distributor plug that is used now is the violet/grey which is the CPS pickup signal, and the power feed right next to it which is the "sensor reference rail" from the PCM (shared among the EGR, MAF, etc). Runs like a champ!

The main difference is the raw power feed, which I adapted from the HEI/TFI mod used on Jeeps, as their coil supply circuit is not enough for these coils either - this isn't a problem with the KL because they have large coil feed wires on their secondary connector while Z5 only has the tiny ones. The external coil can't get enough power from that rail, and as such it also drags the rest of the rail down with it. You could leave the coil and guts alone and just chop the wiring, but I like how it looks with just a skeleton of its former self, and the shaft visible. I think I'll paint mine like a barber shop pole, or add timing marks.

[zanik]

do you have some images of the hei mod in the revise post