Hey I have just recently purchased a 1988 SC Mr2. Its automatic currently but down the line I plan on converting it to a manual.
Im having issues with the overdrive system. It seems to work only when it wants to. First few days of owning the car it working fine. You pressed the overdrive button on and you felt the car change into overdrive. Turn it off and you felt the car change out of overdrive.
The last few days how ever when you press the overdrive button the light on the dash with go out (meaning its in overdrive) but the car itself wont change down. Its not helping my fuel consumption (. Just the other night i was driving and it wouldnt change down into overdrive..............after taking off at an intersection quite quickly in low gear then moving it into drive once i hit 50km/hr i then tried flicking it into overdrive and it actually changed into overdrive.
Anyone have experience with this and know the cause? Anyone also able to tell me how the overdrive system actually works.
Is your car's engine getting up to temp.
A faulty thermostat can play havoc with the tranny.
If it's an electroinc type tranny (ECT)whicj I'm pretty sure it would have, then the engine needs to be at certain temps for 3rd and O/D to engage.
I recently put a newer 5mge donk into my Cressida to replace the the old 5me. The newer engine has an electronic tranny and I had troubles getting the ECU to change into 3rd and 4th. I have since figured out that for 3rd gear and 4th to engage then water temp need to be a least 35degrees+ for 3rd and for forth gear the temp needs to be around 55 degress+. My thermostat was jammed open so it took forever for 4th to engage if at all. 3rd usually came into play after a minute or so after the engine was started from cold.
It can't be the tranny solenoids because for O/D both solenoids are off, unless one is jamming. The two solenoids are used for 1st,2nd and 3rd engagement, besides a fault code will appear if a main solenoid is faulty. The O/D cluster lamp should be the check lamp for the ECT ECU too.
I might be on the wrong track but it's a start. The temp sender could be dicky too, is the car hard to start from cold, ie does it take a few seconds to fire whilst cranking.
its not hard to start........it changes into 3rd no worries at all.......i would have to say the thermostat isnt stuck upon because it doesnt take long for the water termerature to rise to about just below half
its not hard to start........it changes into 3rd no worries at all.......i would have to say the thermostat isnt stuck upon because it doesnt take long for the water termerature to rise to about just below half
If you're keen, I would check to see if the ECT ECU is giving the transmission solenoids the correct signals. The ECT ECU and engine ECU sit behind the glovevox of my cressida. I have setup 3 different coloured 12V LED's in my glovebox. These are wired directly to the outgoing solenoid wires from the ECT ECU and tell me exactly what the ECT ECU is trying to do. There is a LED for each solenoid. S1 solenoid LED is red, S2 is green and the S3(torque convertor lock-up) is blue. Quite interesting to watch. I may have the wiring diagrams for your car on my PC somewhere to help identify which wire is what.
S1 on/S2 off is 1st gear
S1 and S2 both on is 2nd gear
S1 off and S2 still on is 3rd gear
Both S1 and S2 off is over-drive.
S3(TC lockup) comes on after 2nd in engaged, when the car is cruising and turns off if a gear change occurs.
It could be a tranny hydraulic or mechanical problem but I'd suss out the electrical side of things first.
Does your car have cruise control? If so, turn that off and try again.
Other than that, I've run out of ideas. Sorry I can't help any further.
Good luck.
Sat, 16 October 2004 23:57
