Tranny locked in Limp mode....

[NeonHomer]

I just aquired a 93 Eclipse GS N/T w/ the 1.8L engine.. and a 4spd tranny. I just had to replace the motor (the old one had a hole the size of my fist in the back..)

Engine runs fine now... but the tranny is locked in 3rd gear, what I assume to be Limp home mode. I checked the TPS, and I have it set to .50 VDC with the throttle closed. It stays in 3rd even when you put the shifter in L or 2. Also it will not downshift when the throttle is pressed to the floor.

I checked the main harness that goes into the tranny, and I am getting battery voltage on three pins. (on the engine side of the harness). I cleaned the harnesses out with electronics cleaner to no avail.

According to the previous owner, the ECM was replaced, along with the tranny. I have run out of things to check... any help would be appreicated on this!!

 

[NeonHomer]

This is an update to my eariler post...

I went out and pulled the two pulse generators out. Something was odd... There are two generators.... one forward one aft (in relation to the car....) One is over what looks to be a clutch drum, and the other is over a worm-style gear. One has a black wire cover, one has a clear cover and a bit longer wire...

The way it WAS.... the clear wire cover sensor was in the "front", and the black was in the rear... I switched them around, and the wires seem to "fit" better with the car (not a big bunch of wire and such..)

Then there is the switch on the gear shift shaft. Is there a pinout of this switch to make sure it is okay? It seems to be okay... but I dont know...

MORE INFO:

Only one of the pulse generators has a magnetic "charge" on it. The other dont.

Any Help?

 

[Old Mitsu Tech]

Well, the pulses generator connectors and the shift sholenoid connectors will interchange. On some cars the wrong way looks better than the right way. Check that first. If that's not it you will have to check the shift wires for voltages. I don't have the specifics but in first one is hot, in second the other is hot with the first being cold. "no 12 volts" in third you have no voltage on either wire. This is limp in mode. If you have these voltages and it won't shift then it may be the solenoids. If no voltages exist then possible wiring, or tcu transmission control unit can be bad. I need to know if the orange wire and the yellow with tracer wire are getting the voltages. These are on the front of the trans near the oil pan. Post back

Good Luck

 

[NeonHomer]

Also to add.... I went to pull TCU codes last night. Following the procedure outlined here on the site, I was not able to get ANYTHING!!!

I check the ECU, and I get the S-S-S-S-S-S-S pulse, telling me there are no codes.. When I do the same to the TCU pin.. I get NOTHING... So I am thinking maybe the TCU is dead..

I have three wires in the shifter switch (the switch that goes around the shift lever shaft) that have battery voltage with the key on.....

I will check the specified wires and get back to you.

 

[NeonHomer]

Another update...I pulled the TCU out to check for bad capacitors and cold solder joints.

From reading, this seems to be the wrong TCU... It has 3 plugs (thats right), but the Part # is MD738998. The car is a 1993 Mistubishi Eclipse GS N/T w/ the 1.8L engine and 4spd tranny.

Time ran out on me before I could put the TCU back in and check the wires.... I will do it tomorrow in the daylight... that and I have to get a new battery for my multimeter....

 

[NeonHomer]

Well, after much deliberation, a confirmed working TCU, and an awesome deal, we are going to swap over to a 5spd. The auto tranny is already out. We are just waiting for tomorrow to go to the wrecking yard to get the tranny and stuff....