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Speeometer experts needed

7K views 101 replies 9 participants last post by  zkruly87 
#1 · (Edited)
So I started a thread "Bet u havent seen this b4" where my speed sensor shorted and burned up/melted and the speedometer stopped working, obviously.

http://www.3si.org/forum/f35/bet-u-havent-seen-b4-657722/

Since then, I have received a replacement pigtail connector that I soldered into the engine wire harness hooking the wires up correctly to the existing wire color code. (yellow, black, black w/white) and have now tried two separate used speed senors. However, the speedometer is still not working... no cruise or active aero either. Everything else works, fuse 11 is good.

I have tested for positive and ground at the pigtail connector and are getting both, but not from the wires I was told by escape-performance going by the wiring diagram he was using.

Fact- my positive wire is solid black and ground wire is black w/white stripe, yellow is of course the wire going to the ecu. His diagram said the opposite though- solid black is ground, black w/white is positive... but that's not the case with my 1991.

At any point did Mitsubishi switch/change the engine wire harness section going to the speed sensor so that the sensor's ground wire was solid black and positive was black w/white? I can tell that the pigtail is from a newer year as my "yellow" wire is more of a dingie yellowish clearish looking rubber, but the wire coming out of the pigtail is a nice solid yellow.

Hopefully tonight I will have the time to send 12v to the yellow wire at the pigtail, and using a test light at the ecu connection confirm that the yellow wire is still good all the way to the ecu. If it is still good as I think it will be, then what else could my problem be? The bottom gear section still seems to be fine as the pin won't turn, but I haven't pulled it out to confirm 100%.

Could the ecu have gotten screwed up when the sensor fried? (eveything else works and car still runs great though?!) Or is it just bad luck with the used sensors both being bad? Escape-performance sent me another used replacement already at his expense but it's still a no go as well. I'm positive it's not the gauge cluster because cruise isn't working so it's surely sensor, connection or ecu related.

Any input is greatly appreciated!!
 
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#93 ·
I think I'm out of ideas too...:p

Yeah, I don't think you'll hurt anything by swapping the wires. I just hate leaving mysteries behind. You never know when they'll bite you in the ass.
I just hope the sensor wasn't damaged before.

FWIW I'm using a '91 factory Stealth manual and the wires agree with what you guys are saying so I don't think it's an "early year" problem with the color code.
 
#95 ·
One more question Steve, the ground (blk/wht in my case) likely comes from over by the firewall? If so, I see no way how that could have switched by itself and I don't seemingly have any shorting going on.

Also, do you know where the +12 comes from? Battery to engine harness and back out?

My car is a :wizard:
 
#96 ·
Yeah. The ground is listed as Ground Point 2, which the manual shows as the negative battery post but I don't think that's 100% accurate. The manual shows two wires on the battery but there's only one. I think GP2 is that screw I showed you. That screw has two wires on it.

I'm not sure what you mean by "back out" but the 12v comes from the battery, through the ignition switch, to fuse 11 under the dash, to the sensor. With all kinds of stops along the way....
 
#97 · (Edited)
Yeah. The ground is listed as Ground Point 2, which the manual shows as the negative battery post but I don't think that's 100% accurate. The manual shows two wires on the battery but there's only one. I think GP2 is that screw I showed you. That screw has two wires on it.

I'm not sure what you mean by "back out" but the 12v comes from the battery, through the ignition switch, to fuse 11 under the dash, to the sensor. With all kinds of stops along the way....
Oh yeah... duh.

Anyway, my negative battery cable does have two stock wires hooked to the one battery connector, if that's what you are referring to. You can even see them in my sig pic in front of the washer fluid.

EDIT- For more detailed info... that 2nd wire I'm referring at the battery post leads to the firewall just to the left of those 2 small wires you mentioned. In that pic you posted, it's the biggest bolt.
 
#98 ·
THANK YOU FOR ALL YOUR HELP EVERYONE! :thankyou:



I can't explain it, probably nobody can... but after hooking up the black wire to the black/white wire going to the harness (and vice versa) IT WORKS!

I am VERY happy right now!!

But it still has me like :thinking::wtf:

Factory defect that they resolved at the factory?? Who knows!
 
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