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Author Topic: Mixture Issues '86  (Read 1025 times)

Offline Mortuus

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Mixture Issues '86
« on: 06:29:40 PM / 23-Aug-07 »
So I'm trying to set the mixture ratio on my '86 CA20E (black valve cover).  

If you're reading this, Indy, this is your old car.  

I have the factory shop manual.  

The problem is that the ECU LEDs don't blink for the mixture.  They'll blink codes when the diagnostic switch is ON, but I don't get the mixture blinks.  

When it's running, and the diagnostic switch is OFF, it's supposed to do the mixture blink thing, correct?  

One thing that bothers me is that the sticker on the ECU says that it's for a 1984-85 only.  This is an '86 car.  I'm guessing that'd be a non-original ECU.  Did the 84-85 ECUs just not display mixture info?  Can anyone with an '84 or '85 confirm this?  

The other thing is, I get a code for a non-functional neutral switch.  I wouldn't have expected that to stop the mixture displaying though...
« Last Edit: 07:08:26 PM / 24-Aug-07 by Mortuus »

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Offline 200sxkitcar

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Mixture Issues '86
« Reply #1 on: 12:21:14 PM / 26-Aug-07 »
I don't believe the 85 could do that, but i'll have to check my FSM.  There may come up trouble codes when there isn't any, you have to look at the FSM loaded up here to see what I mean.  Before actually starting, if you press and release the clutch, that code should go away.  The computer is looking for that input, if it isn't there (if you can start it w/o pressing the clutch) then it will flag a code regardless of whether or not you press the clutch first before starting.

On the later cars, you had to enter the mixture mode by watching the blinks for which mode you wanted and then turning the screw, which would get you into that particular funtion, but I'm not sure if the 85 had this feature.
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Offline Mortuus

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Mixture Issues '86
« Reply #2 on: 05:29:34 AM / 27-Aug-07 »
Thanks, I'd appreciate it if you could check your FSM to see if the '85s could show mixture blinks.  If it helps, my 1986 FSM has it under "diagnostic procedure - driveability" on EF&EC-38.  

I don't know, this might be the original ECU.  There aren't any paint marker scribbles on it to suggest junkyard.  Maybe all the early '86's  say "for 1984-1985 only" on the sticker.  I'd go have a look at my turbo  car to see what it says, but it's 100km away.  
   
    And yeah, I'd gathered that the later ECUs had different modes you could enter by watching the numbers flash, and jumping in at a certain number.  Mine definitely isn't one of these.  

So, I can see there are at least two versions of the ECU:
-The later version with the different modes, selectable by number.
-The one described in my 1986 FSM.  Which blinks codes when the screw is turned on, and blinks mixture the rest of the time.  

If those ARE the only two versions, then I've got something wrong.  

As for the neutral switch code...  Pressing and releasing the clutch, in my case, definitely does not make the code go away.  The manual says to shift it into 4th or 5th and then back to neutral to clear the code, but that's not doing it either.  

It is a real code, I can't clear it.  The switch itself is on the right side of the tranny and it's supposed to be "on" when the shifter's in neutral.  I ran the ohmmeter on the wiring harness for it, and it doesn't close the circuit in any gear position.  Therefore my neutral switch ain't workin'.  Wonder if I can get at it without dropping the tranny...
« Last Edit: 05:40:09 AM / 27-Aug-07 by Mortuus »

Offline Mortuus

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Mixture Issues '86
« Reply #3 on: 07:45:50 PM / 06-Sep-07 »
I went down to the nissan dealer today and had a look through a 1985 FSM.  The 85s ARE supposed to do the mixture blink thing.  So, that it's an 84/85 ECU shouldn't be the cause of the problem.  

I also swapped out that bad neutral switch for a functional one.  It doesn't throw a code for that anymore.  But of course that made no difference.  Still no mixture blinky leds.  

Any thoughts?  Bad ECU?