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Wiring wiseman needed

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ghostwritr

15+ Year Contributor
43
0
Jan 31, 2007
Mesa, Arizona
I am in the middle of a AT to MT and motor swap on a '98 GST & have run into a wiring issue...

I wanted to do as clean of a swap as possible, to ensure that there weren't any issues with jumping wires, cruise control or the reverse lights and no extra plugs in the engine bay, so I have the wiring harness from the donor car ('97 Spyder GST) that I was going to swap in.

The problem that I have run into is that there are more/different connections in the interior of the car.

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=harness.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/harness.jpg" border="0" alt="Both harnesses with plug descriptions"></a>

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00167.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00167.jpg" border="0" alt="Under seat connections"></a>

I'm sure that someone has ran into this before, but I couldn't find anything when I searched. I am not scared to rewire (ok, maybe a little...) but am not sure that it is even necessary, so I am hoping someone can advise.
 
Got the underdash unknown one figured out...

It connects to the shifter, so it evidently is the feed for the TCU to shift gears, etc... and is not necessary.

On to the next connection...
 
Ok, next connection...

Here is the underseat harness with 5 wires from the automatic:

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00183.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00183.jpg" border="0" alt="Underseat harness"></a>

The 2 blue wires (blue w/red stripe, blue w/white stripe) connected to the small ECU plug, in between the 2 yellow wires and the yellow and pink wires:

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00184.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00184.jpg" border="0" alt="Photobucket"></a>

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00185.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00185.jpg" border="0" alt="Photobucket"></a>

The green w/yellow stripe wire ties in to the same colored wire a little ways up from the second largest ECU plug:

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00186.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00186.jpg" border="0" alt="Photobucket"></a>

The red wire ties in to the harness at the same point as the red wire coming from the O2 sensor and combines with the red wires coming off of the largest ECU plug.

The black wire ties in with a black wire that, in turn, joins in with the green-encased black and white wires from the O2 sensors.

These wires are not present on the harness from the manual transmission car. Can anybody help me identify the purpose of this connection please?
 
So a trip to the stealership today and pulling back the carpet on my '99 GSX provided some information...

The harness is also there in my GSX, but only has 3 of the 5 wires. From the dealer schematics, these 3 wires are shown as going to the rear hatch harness. As the donor car is a '97 Spyder, this explains the complete lack of this connection. :sneaky:

The blue wires, however, remain a mystery. There is not any mention of them in the dealer schematics either. WTF

I guess that I'll be pulling up the carpet tonight and tracing wires... :ohdamn:
 
i did the auto to 5spd swap on my 95 talon awd, the donor parts came from a 95 talon gsx 5spd (crashed car) the wire harness i swapped just like you. i didnt want the stupid auto harness with all the un-used plug-ins. any how what i found is that the chassis harness is slightly differant from auto to 5spd. so when you plug your 5sp engine harness into your auto chassis harness there will be a few differances. im not sure about those mystery wires from your pictures, but i can tell you that under the dash when you installed the new brake pedal and the clutch pedal assembaly. theres a extra plugin that loooks like it should be pluged in. but if its connected it makes the brake lights be stuck on forever. it looks like a clutch pedal position sensor plug in and theres two of 'em under there. if there both pluged in you get brake lights forever. i spent a entire day messin with the ass end of the cars wiring. even took the tail light wire harness from the donor car and it made no differance. my cruise controll was eliminated but i do have reverse lights. i got my 5spd up and goin in like a week. im sure everything will turn out just fine for ya man. good luck and sorry i didnt even really awnser your question.
 
i did the auto to 5spd swap on my 95 talon awd, the donor parts came from a 95 talon gsx 5spd (crashed car) the wire harness i swapped just like you. i didnt want the stupid auto harness with all the un-used plug-ins. any how what i found is that the chassis harness is slightly differant from auto to 5spd. so when you plug your 5sp engine harness into your auto chassis harness there will be a few differances. im not sure about those mystery wires from your pictures, but i can tell you that under the dash when you installed the new brake pedal and the clutch pedal assembaly. theres a extra plugin that loooks like it should be pluged in. but if its connected it makes the brake lights be stuck on forever. it looks like a clutch pedal position sensor plug in and theres two of 'em under there. if there both pluged in you get brake lights forever. i spent a entire day messin with the ass end of the cars wiring. even took the tail light wire harness from the donor car and it made no differance. my cruise controll was eliminated but i do have reverse lights. i got my 5spd up and goin in like a week. im sure everything will turn out just fine for ya man. good luck and sorry i didnt even really awnser your question.

Hey brother, tried to PM you but you have your settings such that you are not accepting any.

Thanks for the info on the under dash plug. If I have any problems with the brake lights I'll know right where to look.

So far, I have traced the wires back to the rear of the car... I will post where they end up connecting to.
 
OK, so I traced the wires around the cab of the car:

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00187.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00187.jpg" border="0" alt="Photobucket"></a>

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00188.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00188.jpg" border="0" alt="Photobucket"></a>

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00190.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00190.jpg" border="0" alt="Photobucket"></a>

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00189.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00189.jpg" border="0" alt="Photobucket"></a>

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00196.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00196.jpg" border="0" alt="Photobucket"></a>

And here's where I ended up:

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00192.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00192.jpg" border="0" alt="Photobucket"></a>

Here's the offending wires (blue/white, blue/red):

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00191.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00191.jpg" border="0" alt="Photobucket"></a>

So now I have to chase this down the rabbit hole:

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00195.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00195.jpg" border="0" alt="Photobucket"></a>

Anybody know what all this connection controls?

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00194.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00194.jpg" border="0" alt="Photobucket"></a>

Or does this mean anything to anyone?

<a href="http://s292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/?action=view&current=DSC00193.jpg" target="_blank"><img src="http://i292.photobucket.com/albums/mm4/ducducgoosed/GS-T%20conversion/wiring/DSC00193.jpg" border="0" alt="Photobucket"></a>
 
According to my 99 factory wiring diagrams: The blue-red (ECU pin 55) goes to pin 2 of the evap emission ventilation solenoid. The blue-white (ECU pin 61) goes to pin 1 of the fuel tank differential pressure sensor.
 
According to my 99 factory wiring diagrams: The blue-red (ECU pin 55) goes to pin 2 of the evap emission ventilation solenoid. The blue-white (ECU pin 61) goes to pin 1 of the fuel tank differential pressure sensor.

That's actually really interesting...

I have the same question posted on DSMTalk:

ECU help - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com

and one of the replies asks

"Does this have anything to do with a NT Spyder? Pin 55 is evaporative emmisions solenoid and 61 is fuel tank differential pressure sensor; however they only show up under the NT spyder MPI wiring specs?"

I looked at my '99 GSX AT & it has the same harness under the seat, but only has 3 of the 5 wires that the GST has, with the blue ones being the missing wires.

Makes me wonder if this is a California emissions thing since the car originated there.

Wow man that looks tough. Good luck! :hellyeah:

Yeah, it's definitely a PITA...

Good thing I planned on swapping out the cloth interior for the leather out of my GSX, otherwise I'd probably be pretty pissed that I had to pull it all out.

I'm being anal about trying to make sure that everything is accounted for because I don't want any surprises. Surprise breakdowns in Phoenix suck this time of year.

I just can't wait to get this done so I have a fun dd while I'm building my next project - a '97 Spyder that will be getting the GSX treatment & a built motor...
 
hey if you run into any problems i could probably help you. i succesfully did the swap and remeber all the things needed to pull it off. 208-553-3123 Tristen. Show Printable Version Email this Post #5 (permalink)
dsmcurse
New Member/Lurker


Car: 95 Talon TSi AWD
From: Lewiston, Idaho
Registered: Aug 2009
Tech Posts: 78
Photos: 5
Reputation: this swap is very easy. if you have a doner car with all the stuff you have it made. i did a auto to 5spd swap on my gsx. gsx swap is a little more in debth do to the fact that you have to swap rear ends. the rear diff has differant ratio than the center diff. so doin a auto to 5spd on a 4wheel drive requires rear end swap. but any how, yes there is a small cable (about the size of a bicycle brake cable) that goes from the key tumbler to the auto gear shift. this is the mehcanism that makes it so you can only take the key out when car is in park. once you get plastic off aroound the ignition it will make total sense. eliminate this all together you wont need it no more. next, after you get the center consoul out you will see how the shift tower bolts down to the flooring with just 4 bolts the auto shoots just one cable through the fire wall. remove all this of course. the manual shift tower has the exact same bolt pattern. new shift tower just bolts right in but shoots 2 cables through the fire wall. the hole doesnt need to be modified. youll notice the the rubber gromit that came with the auto cable is the same outside shape as the one for the 2cable gromit the 5spd uses. next will be putting in the pedal assembally. your super wide brake pedal needs traded for the normal lookin 5sd. the clutch pedal assembally is cleverly mounted in a box type deal. this clutch pedal bolts right in, the stud and bolt holes are already there. next is the master cylinder for you clutch fluid. you notice from the inside of the car (take driver seat out and lay down in there, other wise youll be yoga man standing on your head trying to do this) that the fire wall is 2 layers of metal thick. the first layer of metal is already cut out for you, look youll totally see what im talkin about, its like a template, there really isnt alot of room under there to cut out this second layer of metal. some people are gonna tell you that you have to take the dash out to cut the hole for you master cylinder assembally. YOU DONT HAVE TO PULL DASH. get a angle drill and a step bit. Bam, you now have hole in fire wall in excact spot for master cylinder. go in the engine bay youll notice that where you would bolt the master cylinder up the auto cleverley has some little painted discreet stickers covering up the threaded bolt holes. just look. the stickers are small little dots painted the same color as the engine bay. peel them off and wamo you have the threaded bolt holes to tighten down your master cylinder. next is running the fluid line. I TOOK MOTOR OUT TO DO THIS. trust me man just pull the motor and auto tranny at the same time to do this swap. i think it would be impossible to run the factory fluid line if the motor was still in there. maybe you can get a custom stainless steel braided line to go all the way from master to slave. I dont know. i used the factory one. and youll notice all the bolt holes are there to use the hangers to securley attatch the line to the fire wall. dont use the auto wire harness if you dont have to. yes it will work but there will be so much unused connectors hangin out just lookin ###. you have doner car you have 5spd harness use it! the 5spd engine harness plugs into the auto chassis harness no problem. this is all plug and play dude. the wiring is not scary. once you have the motor and trans out, unplug the engine harness from the chassis harness (down low kinda under passenger side fender) and unplug the 4 connectors off the ecu (under center consoul that you already took off) and pull the harness out of the fire wall. the 4 plastic plugins that are inside the car that you took off the ecu, they will slip through the rubber gromit and pop outside. take 5spd harness and feed the 4 plstic plugins through that fire wall gromit and plug back in to ecu. the auto ecu will work. or just for good measure use the 5spd one. might as well if you have it. you say you have the donor car right?. built into your auto chassis harness that is already installed in your car you will find the clutch pedal position sensor it will plug right into you clutch pedal assembally that you installed. this is your nuetral safetey switch. shoulda mentioned this earlyer. the auto has 2 ecu's. a brain box to controll motor and brain box to controll auto tranny. youll totally know which is which. jst unplug auto ecu and take out of car. as far as using you auto axles in the 5spd tranny. im not 100percent sure. i used the 5spd axles and hub assemballys. maybe some one else on here can tell you about the use of auto axles. like i said if you have donor car and everything is there. than use the whole entire hub and axel assembally just for good measure. if there in good shape of course. trading wheel hub assembaly is very easy, its all self explianitory just from lookin at it. tradin hub set ups will take like a hour per side. this is already gonna be a weekend long project any how. good luck and keep us all posted on the work
 
Well, sh*t, so much for that idea... :aha:

Upon further research, it would seem that all 2G DSMs are California compliant, so the wires can't be specific to California emissions. :ohdamn:

I also pulled the ECU, and it is the one it should be - MD346675, the normal '98 GST ECU...

So I still have no f'n idea what those 2 stupid wires are. :banghead:
 
I had to put this project on hold for quite a while, but got out to the garage today & traced down the offending wires the rest of the way.

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In breaking out the wires from the tape, I was able to find that the wires in question went 2 places:

First, this plug:

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Plugged into this connection on the tank:

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Which is Mitsubishi part# MD322973, otherwise known as the fuel tank pressure sensor.

Second, to this assembly, found behind the gas tank:

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Where this plug is found:

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So, it would appear as though this is all emissions related. But the questions still remain of whether it is all necessary to pass emissions testing & whether it is worth splicing the wires into the harness that I am putting in the car...

By way of comparison, here's a pic of the gas tank wiring in my 1997 Spyder GS-T:

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