Announcement

Collapse
No announcement yet.

HEI mod in a `95 (no external coil)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • HEI mod in a `95 (no external coil)

    When my ignitor started showing signs of eventual failure, I read every thread I could find on the $20 ignitor mod that Joe Bialy conceived. Unfortunately, it wasn't clear to me how to apply this mod to my 1995 GT. There were conflicting claims about the differences between 93-94 and 95 distributor wiring, and it took several threads, a few non-Probetalk sites and my Haynes manual to gain enough confidence that I'd do it correctly.

    For the benefit of those of you who want to try this mod on your own `95s, I'm opening this thread to document how I've done it on mine. I don't know if there are significant differences between `95s and the `96-`97 cars, so I can't give you any assurance that the same wiring scheme works for later model years. I've put about 1,000 miles on since this mod and have noticed no problems. The HEI runs cool, even after an hour on road (of course, my heat sink is kind of overkill.)

    Please read the sticky, "$20 Ignitor Replacement/upgrade" first, as this isn't intended to be a complete tutorial on how to perform the HEI mod; just how you apply it to a `95.

    The most significant difference between the `93-`94 and `95 distributor wiring is with the three pin plug. For the earlier model year cars, the splice from wire #1 (closest to the front of the car; the left-most pin when looking straight into the plug with the connector latch facing up) goes to HEI pin C, and the splice from wire #3 goes to HEI pin B.

    The wiring of the plug changed for `95. For `95 GTs, a splice from wire #2 goes to HEI pin B, and a splice from wire #3 goes to HEI pin C:
    http://i55.photobucket.com/albums/g1...y/HEIfor95.jpg

    For mine, I also grounded the #4 wire on the 6 pin connector (the one that connects to the 5th pin slot in the connector; #3 is a blank.) From what I've read, grounding and heat management are critical for long HEI life, so make certain you have a good ground for both the W pin on the HEI, and the metal chassis of the HEI itself. A heat sink is also recommended. The picture links below show where and how mine is mounted, and the heat sink. My heat sink was cut down from one I salvaged from a server power supply, and is probably overkill.
    http://i55.photobucket.com/albums/g1...HEImount00.jpg
    http://i55.photobucket.com/albums/g1...HEImount01.jpg
    http://i55.photobucket.com/albums/g1...HEImount02.jpg
    http://i55.photobucket.com/albums/g1...HEImount03.jpg
    http://i55.photobucket.com/albums/g1...HEImount04.jpg
    http://i55.photobucket.com/albums/g1...HEImount05.jpg

    My HEI mounts to the heat sink, which itself mounts to a metal bracket I cut. That is mounted to a metal strip between the Diagnosis plug box and the fuse box. I relocated a ground to another existing hole in that strip to make room for the bracket. The HEI's body is grounded via the heat sink and bracket assembly, but to be safe I added a dedicated ground wire. I also used thermal paste between the HEI bottom and the heat sink.

    Please reply if you have any questions and I'll attempt to answer them. Thanks to all the Probetalkers who pioneered this mod, and to Club Protoge, who documented this mod for `94-`95 cars and from whom I snagged pix of the disty plugs (http://www.clubprotege.com/wil/howto/hei/index.htm)
    Black `95 GT MTX
    stock daily driver

  • #2
    Nice work

    Comment


    • #3
      Hi.
      Can somebody help me? I got -95 millenia, and I think that ignitor is going out.


      But I just have 2 wires in plug C170. And that wire what goes in HEI-plug C, idont have at all. So does anybody knows how I wired that plug C170??
      thx..
      Last edited by depoteus; May 24, 2011, 01:30 AM.

      Comment


      • #4
        HEI Module Wiring for 95 GT In Question

        With all due respect to "FeelMyApathy" I think his wiring for a 1995 GT is incorrect. After wading through pages of threads on HEI module installation, I have concluded that the wiring shown in the thread above has improper connections for the 3 wire connector. Since there are no wire colors or signal names mentioned I only have the diagram and the text to look at. Here is my thinking based on my reading and the wiring of my '95 GT.

        The wiring shown for the 6 pin connector is just fine. Pin #6 (Blue/Orange) is indeed the trigger signal from the ECU and should be connected to the "G" terminal of the HEI module. Pin #5 (Black) which is the module's original switching transistor's ground can be disconnected and grounded with the HEI Module grounds "W" terminal. No problem so far.

        Now the 3 pin terminal connections should be looked at. On the 3 pin connector, Pin #1 is the left-most pin when looking straight into the plug with the connector latch facing up. On my vehicle this wire (Black/Pink) is the V(Bat+) 12V signal from the ignition switch. This wire should be spliced into and sent to the HEI "B" terminal. Pin #2 (Yellow/Green) is the middle wire and is the coil negative (-) wire which should be spliced into and sent to the "C" terminal of the HEI module. (For info only, this wire is also the tach wire in our "Data Link Connector") Pin #3 (Green) is also a coil negative wire but with a resistor in-line which feeds the vehicle tach. This wire is left alone.

        Remember, these instructions are for adding only the HEI module but still using the original vehicle coil on a 1995 GT.

        If I am correct, "FeelMyApathy" needs to change his HEI terminal "B" wire to splice into the bottom wire of the 3 pin connector in his diagram while the middle wire should go to the HEI "C" terminal. The spliced wire on the top wire of the connector should be removed.

        Check this out . . . tell me if I'm wrong. If I am wrong, my apologies but tell me where. Thanks.
        Last edited by Cougar; August 12, 2011, 06:11 PM.
        '95 KLZE PGT - SPEC Clutch, Borla Exhaust, Hot Shot Headers, LSD Trans, MegaSquirt, Supercharged

        Comment


        • #5
          Just came back from test riding my '95 after I did the HEI module mod (using the original coil) and the wiring as I discussed in the thread above is correct. The car runs great!
          '95 KLZE PGT - SPEC Clutch, Borla Exhaust, Hot Shot Headers, LSD Trans, MegaSquirt, Supercharged

          Comment


          • #6
            I just followed the 95 with original coil instructions and as cougar had said the diagram for the 3 pin harness is incorrect... I tried it with no fire. I then RE-wired it as cougar explained and started up with the flick of a key. Just to let my fellow '95ers know so they dont have to do it twice.... Luckily I tested everything out before I soldered!
            95 PGT

            Comment


            • #7
              Thanks for verifying.
              '95 KLZE PGT - SPEC Clutch, Borla Exhaust, Hot Shot Headers, LSD Trans, MegaSquirt, Supercharged

              Comment


              • #8
                I'm about to do this like right now.... But I have a question. the HEI module I got came with grease tho apply to the metal side of it. Will I need that? I don't plan on using a bracket, I got me some self taps I was going to just screw it to the body somewhere.
                My Mazda Moves

                Comment


                • #9
                  The grease is used to help transfer heat between the module and the mount which also acts as a heat sink. Make sure the back side of the module has good contact with the body and use the grease if you can. It won't hurt anything to use it even though it may not be absolutely necessary.
                  '95 KLZE PGT - SPEC Clutch, Borla Exhaust, Hot Shot Headers, LSD Trans, MegaSquirt, Supercharged

                  Comment


                  • #10
                    I did the mod. It works all the wires are correct & the ground is good, but it still stalls after it has been running for a few mins. Any idea what that could be????
                    My Mazda Moves

                    Comment


                    • #11
                      I seem to be having trouble with spark still. I would assume that the problem is the coil I know the HEI mod works being that I couldn't get the car to start until I did it and I had a poor quality cap & rotor. After the mod (as posted above) and putting my old cap and rotor button back I'm still having problems. I'm ordering a new bosch cap and rotor button as well as a new coil from RockAuto.com (Very good prices). I am a very detailed person I plan on posting my result so that it may help others in the future. What is going on with my 626 (same engine and layout as V6 PROBE) is it will get spark for a few seconds then it stop sparking completely unless I let it sit for an hour or so. sometimes it'll run for a whole day sometimes it will run for 15seconds. This is why I think it is the coil. If anyone has any other suggestions....
                      My Mazda Moves

                      Comment


                      • #12
                        still having trouble...
                        My Mazda Moves

                        Comment


                        • #13
                          you might have a bad ecu or damaged wires going to it
                          95 PGT white dd klze / mtx fidanza,maf swapped obx headers 2 1/2" mandrel bent 14.3 sec 1/4mile time
                          94 PGT blue toy de/ze/g4 hybrid/ mtx turbo 5- 10 psi maf swapped aem piggy back, fidanza mandrel bent exaust
                          93 PGT red klde/mtx klg4 intake,wild orchid interior
                          97&94&93 PGT gone
                          DALE

                          Comment


                          • #14
                            That's exactly what I didn't want to hear. Problem is I don't own a ProbeGT. I own it's sister, the 626 V6 (KLDE) & I have no idea where the ECU is on it. What I have noticed though, is that my car will get spark & start if I un-hook the ECT sensor.... but it won't run for long while it's unplugged. I replaced that, & the O2 sensor & have the same results. I even went out & bought another HEI module the other day & re-wired the whole mod. Nothing has changed. If I want it to run (although this only works MOST of the time but not everytime) I have to un-plug the ECT sensor, start it, & quickly plug it back in. There have been a few times though, that the car won't start still with the ECT sensor unplugged. & there have been a few times that once I get it started with the ECT sensor unplugged, It'll die once I plug it back in.... & Like I said the ECT & O2 sensors are Brand new.
                            My Mazda Moves

                            Comment

                            Working...
                            X