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Old 04-06-2010, 05:57 PM   #1
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Default Neutral switch issues- Car runs out of gear but not in- Post "wire tuck"

After doing a mild wire tuck i have ran into a few issues. First off the car runs but doesnt run with the clutch out. Bypassed the clutch switch and cured that problem.

Next issue, when attempting to drive the car and the shifter is put into gear. Thus doing god knows what with the neutral switch on the tranny, the car dies.

Can i bypass this switch too and fool the car into thinking its actually still in neutral while driving it?

This post has got me a bit worried about doing my above idea:
https://www.miataturbo.net/showpost....2&postcount=15
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Old 04-06-2010, 06:03 PM   #2
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Can't say I'm surprised- the neutral switch and the clutch switch are physically wired in parallel.

Why not trace the wiring back and figure out what you broke?
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Old 04-06-2010, 06:11 PM   #3
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None of my trans wires are hooked up and the car works. I mean the wires seriously dangle under the car.
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Old 04-06-2010, 06:17 PM   #4
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The only thing the clutch switch is supposed to do is prevent the car from starting sans clutched. I don't believe there is any circumstance under which the car will not start/operate while the car is out of neutral. I'm under the impression that the neutral switch is used simply to change the way the car idles - and I dont think you would want the car to try to idle while youre putting power to it
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Old 04-06-2010, 06:19 PM   #5
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Quote:
Originally Posted by fooger03 View Post
The only thing the clutch switch is supposed to do is prevent the car from starting sans clutched.
*BZZT*

Wrong, but thanks for playing.

There are two clutch switches. The lower one is the starter interlock. We're talking about the upper one, which goes to the ECU and the cruise controller.

Ref post #5 here: https://www.miataturbo.net/showthrea...233#post443471
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Old 04-06-2010, 08:45 PM   #6
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Quote:
Originally Posted by Joe Perez View Post
*BZZT*

Wrong, but thanks for playing.

There are two clutch switches. The lower one is the starter interlock. We're talking about the upper one, which goes to the ECU and the cruise controller.

Ref post #5 here: https://www.miataturbo.net/showthrea...233#post443471
Agreed 100%, the car wouldn't even run with either of those switches working normally.

I would rather no retrace my steps because that means going all through the loom again. I was kinda hoping there was a simple "cross these two wires together" fix to cure this.

Hustler, your **** isnt even connected? Reverse or neutral?
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Old 04-06-2010, 08:59 PM   #7
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How can I get around this:

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Old 04-06-2010, 09:41 PM   #8
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Quote:
Originally Posted by hustler View Post
none of my trans wires are hooked up and the car works. I mean the wires seriously dangle under the car.
+1

no CC in mine though. don't know if that matters? but I've never connected the two plugs at the gearbox. never. didn't cause a problem with the stock ECU or the current standalone squirt.
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Old 04-06-2010, 10:14 PM   #9
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If you're worried about the switches, try reverse. I also ha both of mine disconnected at one point and it worked fine. Try unplugging the switch and putting a temporary jumper between the terminals. Might be wise to double check with a multimeter to make sure that's what the switch does.
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Old 04-06-2010, 10:39 PM   #10
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Jumped and bypassed the switches, what is this going to do?

I read that it might have something to do with idling, which i posted about in the first post here.

Quote:
Originally Posted by RotorNutFD3S View Post
As it was explained to me the neutral switch tells the ECU when to start closed loop idle timing and air control. Is that fact? IDK.
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Old 04-07-2010, 04:32 AM   #11
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Somewhere I have a sheet with all the ports of the ECU and how to diagnose them. I'll look around for it tomorrow (I just moved so I may be fucked), and it should give you a hint as to what it does.

EDIT: All it says is 0V and bV, and assuming the switches are fine, its only one wire that could be the problem. In neutral or with the clutch pressed you should have 0V. Any other condition = bV.

Though I'm sure you've figured all this out by now anyway.

Last edited by MartinezA92; 04-07-2010 at 10:21 PM.
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Old 04-07-2010, 03:55 PM   #12
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Actually, I am pretty sure those are both only for cruise control. The upper clutch switch (not the interlock) and the neutral switch. They are both safety disconnects for the CC. I can't imagine they have a damn thing to do with how it idles. I know they are wired to the ecu, but I don't think they change how the engine runs. I would bet money if you just found the wire at the ecu that goes to those switches and clipped it, all would be fine.

That is of course based on the assumption that there are no other problems. That all sounds to me like you have wired something up wrong in there somewhere.......
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Old 04-07-2010, 04:23 PM   #13
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I did the exact same thing, pulling wires off, cutting, trimming, and tucking everything away. Car cranked and worked fine. Put it in gear and it dies. Took me at least 10 times as long to untuck and reqire everything as it did to cut it out, I actually ended up pulling the tranny trying to figure it out. I finally found a ground wire near the passenger side headlight that was the problem, once it was grounded the car was fine. What fun that experience was.
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Old 04-07-2010, 05:56 PM   #14
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I cant believe you haven't posted pics of the wire tuck yet.
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Old 04-08-2010, 01:51 PM   #15
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Quote:
Originally Posted by MartinezA92 View Post
EDIT: All it says is 0V and bV, and assuming the switches are fine, its only one wire that could be the problem. In neutral or with the clutch pressed you should have 0V. Any other condition = bV.
This means that the ECU is applying a +12 pullup to the line, and that the clutch switch (when depressed) or the tranny switch (when in neutral) closes the wire to ground and therefore pulls down the voltage to zero. It sounds like the brown/white wire is shorted to something important, and is pulling that line to zero as well.


Quote:
Originally Posted by thesnowboarder View Post
How can I get around this:
I honestly don't know, dude. You're in uncharted territory here.

Disconnect the connector from the clutch switch and also from the transmission. Then cut the brown/white wire at the ECU and leave it hanging. That'll "fix" your immediate problem, and the ECU will just think you're never in neutral.

If you really want to fix it, you'll either have to back-trace your wiring, or run a new wire from the brown/white wire that you cut at the ECU to the brown/white wires at the clutch switch and the transmission neutral switch. Cut the original brown/white wires at both of those switches, and splice the new wire from the ECU to the brown/white wire stub on the switch side of the wiring at both locations. You'll have to run separate wires to the clutch switch and the transmission switch, and basically just abandon the majority of the original brown/white wire in the harness, which you probably shorted to something important somewhere along the way. Just tape up all three cut ends of it and forget about it.

IF, after doing this you still have the problem, then your ECU is fubar. Actually, you can do a quick test for this easily before you run any new wire:

1: Cut the brown/white wire at the ECU as indicated above. Leave it hanging, and start the engine.

2: Now, stip back the end of the wire a little (on the side that goes to the ECU) and short this to ground. If it kills the engine, your ECU is bad. If the engine keeps running, go to step 3.

3: Strip back the end of the brown/white wire that is opposite the ECU, and short that to ground. Did it kill the engine? If so, you fucked up the wiring in the car. Cut it, abandon it, and run the new wires as I indicated above.
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Old 04-08-2010, 08:52 PM   #16
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I ended up putting a jumper between the brown-white wire and black wire on the clutch switch and another jumper between the brown-whtie and black- Currently fixed the issue of it not running ect. When i have more time ill go behind the dash and yank the entire harness and do it all done up properly.

Under the hood pretty much looks like so, with everything together and nicely put away:
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Old 04-08-2010, 10:04 PM   #17
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Quote:
Originally Posted by thesnowboarder View Post
Jumped and bypassed the switches, what is this going to do?
fix it, apparently.
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Old 04-08-2010, 10:35 PM   #18
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Well is there the possibility to reverse the neutral and reverse switch connectors (that could create some interesting problems by just glancing at the diagram). I have done a similar thing with the starter and windshield wiper connectors at the fuse box. Intermittent starter motors are not so useful nor are key operated windshield wipers....
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