Bear with me because it is long and interesting. I am posting this for anyone who doesn't know about this. On my 90 GT Turbo. I was getting no spark at all. So I went to the wrecking yard and got another distributor and coil and ignitor and knock sensor and controller and installed it all. I did this because my friends work there and I got everything for almost nothing. Like 10 bucks. all this before I knew about this absoulutly GREAT forum and all the very knowlegable members. I didn't have any of the tests to check any of the components. So I figured it's cheap why not. So I still got no spark! So guess what I got more of the same parts and did it all again. Still no spark. Time to do some research now. That is when I found all of you. I started doing all the tests in the faqs and everything was correct except the 1G wire (y/b) that was suppose to have 0 volts with the key on (it had 12 volts). The book said that it had a open circuit in the wiring harness. I didn't want to cut into the harness yet, so I checked the grounds and they were all good on the ohm meter. So I cut the harness open and started checking and found this wire that looked like a shield that was broken so I fixed that, and then the other end of it comes out in the same sheath that the wire the 02 sensor is in. Here is a picture of it. http://i200.photobucket.com/albums/a...CGM/mx6003.jpg
Well this wire was not connected on the other end either. So I grounded it because it looked like a ground. Guess what, It started right up! Now is the strange part. I had read about unplugging the power steering control box. I had already unplugged it and had fogot that I had. So I plugged it back in and it would not run. So this is the just of it. If your getting a 12 volt reading on the 1G wire. Try this Before cutting into the harness. If you unplug The p/s box and it still wont run, ground that wire and leave the p/s unplugged. If it runs get a new p/s box and then use the shield as a shield, like it is suppose to be. It doesn't have to be grounded. THANK YOU TO EVERYONE THAT TOOK THE TIME TO HELP. And for all the suggestions.
mfre, I'm scanning in the 90 Wiring Manual for NSXR to put up on the site. If you need a specific part/page of the manual I can e-mail the section to you, i'm still working on the color pages, it's almost done.. KIRK
The actual Mazda MX6 wiring manual has many more sections concerning/diagnosing different systems in our cars. It blows away the workshop manuals small schematic diagrams.. KIRK
I seem to have the same problem, I have tried unplugging the box under the drivers seat but that did not work. The only difference that I see on miane is the wire that should have less than 1V yellow/blue stripe which should be 0-1 Volt is giving me 2.2 V.
I have a 90 gt also and had the same problem until today. Thanks for the info mine runs with the box unplugged.
Anybody have a fix to eliminate the box and still have power steering. I have a 92 lx parts car would its rack and pump eliminate the problem.
Somewhere in the wiring diagram the p/s interferes with the ign tach reference . Not sure if its a failsafe for the p/s system but will update if i can be compromised.
can someone explain to me what the power steering box has to do with the car running? Im a little confused
The GTs have an electronically controller power steering system (ECPS). This means there is a separate computer under one of the front seats that effectively controls the power steering assist level. One of the inputs it uses is the tachometer, another is the speedometer. These allow the power steering control unit to get a better idea as to the level of p/s assist needed. If the box malfunctions, it can short out the tachometer signal as it is physically wired into the box for reason explained above. If the tach signal is shorted out, other units that need this signal (i.e. ECU, engine control unit) also don't get the signal, and car doesn't run.
The DX/LX power steering rack is much simpler and does not have said box under the driver's seat. It only has one electrical component, this is an output to the ECU to tell the engine control units when the rack is being used - I believe this is so the ECU can adjust idle, etc to avoid stalling out. The DX/LX rack could probably be installed on a GT if one wanted to simplify the system.
Just finished reading another "car won't start" thread and found it very enlightening.
A quick question though, is this a GT 90-92 issue only, or do the 1Ga's also have such shenanigans in the power assist system? Just want to be in the know should this leave me stranded someday...
I believe in reincarnation... just the other day i saw an old lady turn into a driveway.
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