420A Auto to manual, speed sensor not working

[Brad Bell]

Using the instructions http://www.2gnt.com/?d=ATMT I did an auto to manual conversion on my 1999 eclipse gs 420a. Everything works fine except the speed sensor I wired up. I wired the three wires coming from the speed sensor to the wires corresponding on the ecu plug. I don't know for sure the wires are the correct ones, so if anyone knows for sure which wires that would be great. The power is going to the sensor, reading around 8.9 volts, but there isn't anything coming out, if so only slightly. The gauge cluster doesn't budge. Someone please help!!!!!!!!

 

[Th3ory]

Tough issue here, I don't know anything about the speed senor. However, if power is being supplied but not transmitted, could the sensor be bad? I doubt its that easy, sounds more as though you have miss wired something, study the ecu pin diagrams and double check yourself, or have someone else step in and trace the wires.

Its tricky because you stated, "but there isn't anything coming out" no voltage leaving the sensor. Does the car need to be in motion before a signal "comes" out of the sensor? IDK check sensor, and retrace the wiring. Good luck.

 

[Flyn2low]

I have done this swap and I know the wiring schematic I found worked right the first time. I'm trying to find if I still have it.

I do know that the speedo will only send a signal from the trans when in motion. My suggestion would be to jack the front wheels up off the ground and have someone put the car in gear and let the wheels turn. They will probably need to ride the brake a little since there will be no resistance on the tires being that they are up in the air. Then you can test to see if you're getting a signal out of the speedo sensor. You can also have someone spin the wheels while the car is in the air with the ignition on but if they don't spin them fast enough you may not get an accurate signal.

The diagram I used is the same as the one you found on 2gnt. Try testing the sensor like I mentioned. That should tell you if the speedo sensor is working.

 

[Brad Bell]

The diagram I used is the same as the one you found on 2gnt. Try testing the sensor like I previously mentioned. That should tell you if the speedo sensor is working.

Where exactly did you tap into the wires listed in the diagram? I tried using a working speed sensor from a donor car and it still didn't give me any reading on the gauge. I have been messing around with this speed sensor for months now and still can't get a signal to the gauge. I have tried numerous tests as well, I removed the speed sensor and spun it very fast with a drill and still nothing. I feel like I am just not on the right wires. Maybe you can post some pictures?

 

[Flyn2low]

I did the conversion about 3 yrs ago but let me see if I can get some pics for you tomorrow. It might not be until Saturday though since I have to work tomorrow. When you tested the speedo were you using a digital multimeter? If so did you have it on AC voltage? I'm actually a mechanic so I'm just trying to think of somethings that we can rule out. Also, my eclipse is a 95 with 97-99 coversion on it so the computers were different for my year. Something else I just thought about, I think I actually looked for the speed sense wire in the automatic trans speedometer sensor so I know I had the right one. I did hear of some people having the same problem as you thou so you're definitely not the only one.

 

[Brad Bell]

Ok

Something else I just thought about, I think I actually looked for the speed sense wire in the automatic trans speedometer sensor so I know I had the right one. I did hear of some people having the same problem as you thou so you're definitely not the only one.

Yeah I'm definitely not the only one haha, thanks for the help though I really appreciate it. So your saying you tapped into a speed sensor plug from the automatic tranny? It would be great if I could get the wire color of that

 

[Flyn2low]

Let me see if I can find it for you real quick. I have access to a data base of different wire schematics and diag testing procedures.

Ok, on the automatic trans they use a input and output speed sensor on the 99 GS. The way it looks from the diagram the the one sensor does both input and output. The plug from the automatic trans that you need to look for will have white/green, white/yellow, and a gray/blue wire in it. The circuit diagram showed them as being separate but the component location diagram showed them as the same. So I would look for a harness with either all 3 of the wires I just listed or it may have 4 wires with an extra gray/blue. If you don't see this harness then it could be a (2) 2 wire harnesses with one being white/green and gray/blue and the other being white/yellow and gray/blue. Either way it will be the white/yellow wire that is needed for speedometer to work. Sorry that it's a little confusing they didn't give me a direct picture of the plug.

Also the proper test procedure for the speedo sensor is as follows:

1. Check the voltage on the Yellow wire at the speed sensor. It should be 8-9 volts.

2. Check the voltage on the Yellow/White wire with it disconnected. It should be 5 volts. Reconnect the sensor and rotate the right axle. The voltage should go from 0 volts to 5 volts 6 times per revolution.

3. Check the ground on the Black/Dark Green wire.

4. Check the pinion gear and the worm gear in the differential

I hope this helps. Let me know if you have any questions and I'll try to help you out. Also if you can't find the plugs I listed in my last post check the main big harness on the trans. The yellow/white wire maybe pin 54.

 

[Brad Bell]

Let me see if I can find it for you real quick. I have access to a data base of different wire schematics and diag testing procedures.

Alright sweet. This is the best info I've had! Thanks! I will try this tomorrow. Yeah I am getting 8.9 volts on the yellow wire. It's good to know though that the yellow with white is 5 volts.

 

[Brad Bell]

Also the proper test procedure for the speedo sensor is as follows:

1. Check the voltage on the Yellow wire at the speed sensor. It should be 8-9 volts.

2. Check the voltage on the Yellow/White wire with it disconnected. It should be 5 volts. Reconnect the sensor and rotate the right axle. The voltage should go from 0 volts to 5 volts 6 times per revolution.

3. Check the ground on the Black/Dark Green wire.

4. Check the pinion gear and the worm gear in the differential

I hope this helps. Let me know if you have any questions and I'll try to help you out. Also if you can't find the plugs I listed in my last post check the main big harness on the trans. The yellow/white wire maybe pin 54.

Okay so I attached the yellow/white wire from the vss plug to the white/yellow wire you said to connect to. Still nothing. I tested the voltage at the plug with the car on the "on" position and I got these reading. Note that I have the multimeter set to dc. I also for a ground used the middle black/green wire. So for the yellow I get 8.9 volts, and the yellow/white I get 0.1 volts. There's still nothing.

 

[Flyn2low]

Ok it does sound like you're on the right wires now. So you still didn't get any voltage when spinning the right wheel? Also, just for the hell of it try testing the yellow white wire at the plug with the speedo unplugged. See if you now have 5 volts. Also, Do you still have the trans computer plugged into the car?

 

[Brad Bell]

Ok it does sound like you're on the right wires now. So you still didn't get any voltage when spinning the right wheel? Also, just for the hell of it try testing the yellow white wire at the plug with the speedo unplugged. See if you now have 5 volts. Also, Do you still have the trans computer plugged into the car?

Yeah I had the trans computer plugged in, mine is under the dash. I tried two different computers . I get no 5 volts anywhere, there something I'm missing I don't know what. I also tried the yellow white wire on the plug for ECU and that didn't work either .

Do I need the engine running?

 

[Flyn2low]

No you shouldn't need the engine running just the ignition on.

Did you happen to try unplugging the speedo and then testing the yellow/white wire to see if you have 5 volts? The reason I'm saying to try this is because if the speedo is bad it could be stuck in a position of 0 volts cause from the test procedure it said as you turn the right wheel the yellow/white wire voltage will move between 0-5 volts. It should do that 6 times within one full rotation of the wheel.

Also, have you tried checking the fuses lately? If you had the wire from the speedo on the wrong vss wire it could have blown a fuse if that wire is a fused circuit. I'm just throwing somethings to try out there for you cause I believe you are on the right wires now so it should be working right unless the speedo is bad.

Hey, is the ground wire you are using, black/green I believe, wired directly to ground or to the wire that the write up said to wire it to?

Let me know how you make out.

 

[Brad Bell]

Hey, is the ground wire you are using, black/green I believe, wired directly to ground or to the wire that the write up said to wire it to?

The ground I am connected to is the black with green. Found at the plug for ECU

 

[dustyboner]

Vss PIN1 (yellow) > Ecu bottom plug PIN44 (yellow)

Vss PIN2 (black/green) > Ecu bottom plug PIN43 (black/green)

Vss PIN3 (yellow/white) splice into wire from -------
---Ecu bottom plug PIN66 (yellow/white)


Ecu bottom plug contains pins 41-80 in the FSM so the 1st pin is PIN41

Eatx-ecm needs to be unpluged or you can cut the wire coming from PIN18 (yellow/white) on Eatx-ecm.

Measured from vss plug to ground (-)
-PIN1. 8v
-PIN2. Continuity
-PIN3. 4.5v or more

 

[Flyn2low]

Ok, I figured you were but just figured it would be good to rule out. I would still try testing the yellow/white with the speedo unplugged to see what you get. You said you haven't tried swapping the speedo sensor yet right?

 

[Brad Bell]

Vss PIN1 (yellow) > Ecu bottom plug PIN44 (yellow)

Vss PIN2 (black/green) > Ecu bottom plug PIN43 (black/green)

Vss PIN3 (yellow/white) splice into wire from -------
---Ecu bottom plug PIN66 (yellow/white)

Ecu bottom plug contains pins 41-80 in the FSM so the 1st pin is PIN41

Eatx-ecm needs to be unpluged or you can cut the wire coming from PIN18 (yellow/white) on Eatx-ecm.


Measured from vss plug to ground (-)
-PIN1. 8v

-PIN2. Continuity
-PIN3. 4.5v or more

Yeah I get 8.9volts on the yellow power wire to the sensor, the ground is connected to the black green wire as you said, and the yellow white wire tapped of the yellow white wire as you said aswell. Still no 4.5volts at that wire though. I can't seem to find that source of power anywhere. I know my sensor is good too cause it came off a car that it was working for

 

[Brad Bell]

Ok, I figured you were but just figured it would be good to rule out. I would still try testing the yellow/white with the speedo unplugged to see what you get. You said you haven't tried swapping the speedo sensor yet right?

The sensor is good yes, I've tried two different ones, still getting same results. No 5 volts

 

[Brad Bell]

Ok, I figured you were but just figured it would be good to rule out. I would still try testing the yellow/white with the speedo unplugged to see what you get. You said you haven't tried swapping the speedo sensor yet right?

Is there a possible fuse? I also notice that near the transmission computer there is a ground cable broken off. I just don't understand how there can be no power on that yellow white signal wire

 

[dustyboner]

Does the yellow/white wire have continuity between the ecu plug and vss plug ?

 

[dustyboner]

The only fuse is #8 10A on the interior fuse box

 

[Brad Bell]

Does the yellow/white wire have continuity between the ecu plug and vss plug ?

Yes there is

 

[Flyn2low]

Now that you verified the wiring, I really don't think you missed anything.
You said that you are tapped into the speedo out plug white/yellow wire correct? This would be the next step I would take in diagnosing the problem. Disconnect the speedo sensor and then unplug the ecu harness from the ecu that has the same white/yellow wire in it. Then put your multimeter on the setting that shows a little dot and what looks like sound waves coming off of that. That is the setting you want it on to check continuity. Now use either the red or black lead and stick one in the speedo harness on the yellow/white wire. While still having the one connected to the speedo plug take the other one, red or black which ever you didn't use, and probe the white/yellow wire at the ecu harness. If you get a tone from the multimeter then you have continuity and the wire doesn't have any breaks in it.

I know your speedo was probably working before but sometimes these wires break easily so during the coarse of your swap there is a possibility that the wire broke. Plus that will now rule out the sensor, plug, wire, and the connection you made as possible suspects if you do have continuity. If you do not get a tone from the meter then you have a break in the wire somewhere. My suggestion would be to run a whole new wire from the sensor to the ecu cause it is usually easier than chasing down where the break is at.

As for the person who said the wire tests over 4.5 volts I am not sure if it tests like that or the way I told you. I got the info on Alldata from another Mitsubishi tech but have not tested it myself to see how it works. So I would check either way if you need to test. Doing the continuity test will tell you a lot about what is actually going on.

Let me know how you make out.

Just seen your post about having continuity. You may have a bad ecu then.

 

[dustyboner]

Just seen your post about having continuity. You may have a bad ecu then.

I agree, the ecu outputs 5v (+) at PIN66 (yellow/white) . If you didnt unplug the ATX ECM, or you had the wiring incorrect at some point, you could have damaged the PCM try another PCM if you have one. As long as its from a 98 or 99, any one will work. If you use an AT PCM, you ll get a CEL cause the ATX ECM is unplugged and the redline is 500rpms lower than with the MT PCM, , >

 

[Brad Bell]

I agree, the ecu outputs 5v (+) at PIN66 (yellow/white) . If you didnt unplug the ATX ECM, or you had the wiring incorrect at some point, you could have damaged the PCM try another PCM if you have one. As long as its from a 98 or 99, any one will work. If you use an AT PCM, you ll get a CEL cause the ATX ECM
is unplugged and the redline is 500rpms lower than with the MT PCM, , >

Okay I tried everything, checked continuity between yellow white wire and plug and it checks out good. Tried two different ECU's , tried two different transmission computers. Still no voltage on yellow white wire. All I get is 0.2 volts.

 

[Flyn2low]

Have you tried rotating the right wheel while testing the wire to see if that voltage changes at all?