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Purge Valve Delete? Stripping Loom To Basics.


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#1 tony g

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Posted 13 November 2020 - 10:09 PM

Im using a stripped down loom for my Cortina project and going the the pinouts for a 90-91 1.6 engine. Can I delete the purge valve without affecting other pins that may take a signal from it. Would it put mil on by disconnecting?

If theres any other do's or dont's to remove/leave in place so as not to upset the stock ECU I'm all ears :)

 

Cheers

 

Tony


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#2 Martin Y

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Posted 14 November 2020 - 03:22 PM

Only Miatas of that age have a MIL, MX-5s and Eunos Roadsters don't. They do store the same fault codes but you check them by sticking an LED into the Diagnostics port.
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#3 Zed.

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Posted 14 November 2020 - 03:49 PM

if you unplug the solenoid on a '91 Eunos the ecu stores a faultcode re the evap syetem BUT seems to run fine otherwise :wacko: 

when I bought my '91 the po had removed the charcoal canister & its solenoid so this is how I know :whistle: 


although I fitted another solenoid to test if there was a difference & noticed nothing apart from the lack of faultcodes :blob: 

Rich.


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50 Shades of Silver. '91 NA6CE, Not a show car :driving: 
Ohlins dampers, goin drysump, EPS, 4.778:1 & more ideas than time :yes:
Bodger :ph34r:

https://mighty5s.com...silver-na-eunos


#4 tony g

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Posted 16 November 2020 - 09:25 AM

Only Miatas of that age have a MIL, MX-5s and Eunos Roadsters don't. They do store the same fault codes but you check them by sticking an LED into the Diagnostics port.

Thanks Martin you may have answered another question Ive got. A friend whos good with ecu's and wiring originally stripped the loom down for me based on a wiring diagram hes got. On pin 1E he had labelled the wire as "power steering pressure sensor" but when I looked at the commonly available diagrams (miata) it says 1E is engine light so that maybe explains why I cant get a (makeshift) bulb to light on the bench when I power up the loom. 

 

So is there an MX5 diagram anywhere so I can follow that instead? Also which terminals would you put an led across in the diagnostic plug - ?

 

Cheers

 

Tony


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#5 tony g

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Posted 16 November 2020 - 09:28 AM

if you unplug the solenoid on a '91 Eunos the ecu stores a faultcode re the evap syetem BUT seems to run fine otherwise :wacko: 

when I bought my '91 the po had removed the charcoal canister & its solenoid so this is how I know :whistle: 


although I fitted another solenoid to test if there was a difference & noticed nothing apart from the lack of faultcodes :blob: 

Rich.

 

 

 

That makes sense too Rich. I measured the solenoid resistance and it was 25ohm so if needed I could solder a resistor between the pins at the ecu to keep it happy but if the only code will be evap related I can leave it as none of that will be there anyway,. :) 

 

Cheers

 

Tony


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#6 Zed.

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Posted 16 November 2020 - 01:25 PM

as an aside, 

 

I've recently stripped an early 1.6 loom as part of a simplification (going with a stand-alone ecu) so have the engine / ecu wiring in my scrap-pile*

 

if you want it as spre plugs etc (probably the whole engine loom??)

 

 

 

 

one of the scrap piles, sorta disorganised chaos but.....


Rich.


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50 Shades of Silver. '91 NA6CE, Not a show car :driving: 
Ohlins dampers, goin drysump, EPS, 4.778:1 & more ideas than time :yes:
Bodger :ph34r:

https://mighty5s.com...silver-na-eunos


#7 tony g

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Posted 16 November 2020 - 02:19 PM

Thanks for the offer Rich but i may have a whole car coming soon with running engine etc. I wanted to see if my stripped down loom would run this engine before I strip it. Does pin 1 E do the PS pressure or engine light on yours? I can find any drawings of anything other than miata which, if they have the light and my loom didnt ive been chasing my tail trying to get a light to work on the bench lol.

 

Cheers

 

Tony


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#8 Martin Y

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Posted 16 November 2020 - 02:47 PM

In the diagnostics port, with the ignition off, you use a wire link to connect the TEN pin to one of the GND pins and your LED between B+ and FEN.  Then you turn on the ignition (but don't start the engine) and the LED should flash to indicate any stored fault codes.

 

You need a 12V LED, or an ordinary LED in series with a resistor (470 ohms is a common value that's ideal).  If you plug it in the wrong way round it won't do any harm but it won't light.  You could check which is its + end with a 9V battery or whatever.

 

The flashing pattern starts with a long flash then a series of long and short flashes for each stored fault code, if any.  Count long flashes for the first digit then short flashes for the second digit, then a pause before the next code.  The pattern will repeat endlessly until you turn the ignition off.

 

The error codes can be googled but there's a nice description here: https://mx5diy.blogs...es-for-mx5.html


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#9 tony g

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Posted 17 November 2020 - 07:41 AM

Thanks Martin, I'l try that method to see if I get any codes  :thumb-up:


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#10 tony g

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Posted 17 November 2020 - 04:56 PM

Well I cobbled up a set of led's which would turn on at 2v on my bench power supply so I put a 1k resistor in and connect into the diag plug (with jumper) and all I got was led's lit continually. Ill need to go through the harness to check for any shorts etc and Ive ordered some 12v led's which should be better suited for the task.

if that doesnt work maybe I need more stuff plugged in to the loom maybe? 

 

Cheers

 

Tony 


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