Try downloading the 89 wiring diagram from this link:
Index of /
It is on this page and also under Mazda
You are pointing to the correct white wire.
Code 34 is the same on the 89 mx6/626 GT, this can cause idle to surge while the ECU chases the preset rpm but can't hold it. This will not prevent the car from starting or running.
The 1989 WSM has no mention of Code 1
The 1988 WSM Has Code 1 : Ignition Pulse (And the 89 ECU will throw code 1)
The only thing the probe has different (That I can recall) are the oil pressure sending unit instead of a switch and the oil level sensor in the oil pan and the wrong logo on the valve cover.
Page 105 and 106:
Before trouble shouting the igniter you should check the grounds for it, on the mx6 they are next to the battery bolted to the inner fender with an M6 bolt 10mm head. There should be four or 5 ground wires meeting together in a plastic plug, the wires are all black with green/gold dashes on the MX6. If this ground contact is loose, corroded or bad the igniter wont fire and the car wont start. But a bad ground here give very weak spark and the engine doesn't usually try to fire twice and give up.
I really hope I am not wasting your time here but I suggest you grab 1 role of black electric tape and start removing the tape back from the distributor plug toward the injectors, follow the two Yellow with blue stripe wires. Eventually you will find them wrapped in green and or yellow tape (about one foot back from the dissi), this is where they are crimped together in the harness and two become one. They are crimped with what looks like a lead cube and the yellow green tape is all that was keeping corrosion out off the wires, the heat cycling of the harness makes the tape turn gooey and that causes the exposed wires to corrode. Even if they still carry continuity there is a chance the can't carry enough current, cut the splice cube out and strip back the wires until you find nice shinny copper, take 1 piece of = or larger size wire and use it to connect the 3 ends. I recommend solder, shrink wrap and tape to make and cover the connections, some people don't like using solder and say it creates resistance but I have never had any issues from soldering wires on wire harnesses, compression and crush connectors I have seen them fail time and time again after the wires corrode or a couple break the rest slide out of the connector and even when the plastic sheath is cut off the connector and it's properly sealed in tape the metal tube still develops condensation.
When you retape the loom over the harness, stard where you stopped stripping tape, tape around the wire bundle a couple time them put the loom over with the tape coming out the seem of the loom and start taping over the loom, tape back over the end of the old tape (where you stopped removing it) and work your way forward to the dissi. When you get to the end flip the tape and go around the harness sticky side up for 1.5 turns then flip it again and do 1.5 turns sticky side down. cut the tape do not pull and break it and don't stretch it too tight while wrapping the harness either. The tape will never unravel this way.
I have had the exact same problem a few times and have purchased cars with this problem over the years, fires up and dies. It has always been harness related for me.
I have had/seen igniter ground problems a few times also (not enough spark to run or start the car).
And I have had a couple ECU's die on 88-89 GT's, the car runs like ass, sputters and missfires, wont rev beyond 3000 rpm, the higher the rpm goes the slower the car moves, if you shift second it stalls...
One of the members here Zach had the fired up and dies issue, he said he found continuity between all the Dissi wires and ECU but changed the harness and it worked.
This was my first post on MX6.com:
Car starts but runs rought and stalls NEED HELP ! TRIED...
In my defense I had no workshop manual or online copies to work with and I joined mx6.com to the day I posted the thread. So all I had was pile of parts and a bunch of guessing.
Maybe for you it's not the dissi wires but it could still be a signal feedback issue caused by the harness.
I say you have gone this far, undo the two other connectors near the ECU on the harness and pop the rubber grommet out of the firewall and move all the connectors to the engine side. Remove the 10mm nut holding the harness to the firewall and free up enough slack in the harness so the ecu connectors are easily accessed at the same height as the intake manifold. Now you can work with a multimeter and check all the ECU to sensor connections. Check the grounds in the engine harness, one bolts to the engine lift bracket next to the throttle body, one bolts to the intake manifold on the passenger side after the #1 injector, I will be honest I don't know where these grounds go but I think they bridge off to ground stuff like the knock sensor, the IAC/BAC valve... and they may go all the way back to the ecu and are used as the injector ground pulse signal for injector bank A and B. The SDS extra injector controller I run does that, it operates two injectors and has two grounds that need to be connected to 2 different ground points on the engine. The injectors are connected to a switched 12V source directly and the unit pulses the ground signal it gets from the block to the injectors.
Try downloading the wiring manual from the link, I tried it recently sometimes it opens in pdf and sometimes it doesn't. Also click on Mazda and grab copies of all the 88-92 GT turbo manuals you can find, it's all very similar and good to have.
Wire diagrams are a pain in the ass at first but the aren't that complicated, I prefer the Mazda WSM to the ford ones but fords part code indexing is better except the fact they used the same code for a ford probe as a pinto.
For the most part any wire of the same color and the same size in the harness is connected/same wire/same signal, even though two separate ground wires of the same color might not meet in the harness they will carry continuity between each other once connected to the frame.
The color abbreviations are fairly simple
R=red
B=black
L=Blue
G=green
Lg=Light green
R/L = red with blue stripe.
If you look at the first workshop manual page you will notice that every device there are two doted lines with two arrows on every wire leaving the device (Knock sensor, crank angle sensor, injectors...) these dotted lines and arrows mean there is a connector there and the EM-26 for example, EM is the harness, 26 is the connector at the dissi.
All the connector pinouts are drawn out at the connection side not the wire side.
The grounds can be a little more complicated because they don't have pinouts just connections in the electronic diagram.
Take the ground 8 for example on the same page. It goes to the knock sensor and also goes to a dotted line on the knock sensor, 5 of the 6 dissi wires and the O2 wire. This represents that ground point 8 connects to a grounding sheath (braided metal sleeve) that wraps around all these wires somewhere in the harness, it does not make contact with any of the wires, it shield then from noise/electrical signal interference. I have seen electrical wire disconnected at both ends in building conduit that's pick up voltage from the 3phase 575V next to it simply from electrical radiation (Not an issue for devices running on power from the conduit but dangerous to work on and requires tracing wires and shutting down more breakers until the wire is safe to work with).
Shit you might just be the unluckiest guy and have a bunch of bad ECU's but I do not want to see you purchase another ECU have the car not start, then you set it on fire and walk away with this look on your face:
