Stalling Engineand Ect

[supracar1995]

I have a 1995 Toyota Supra N/A with 104,000 mi. My engine starts fine but irratically stalls when coming to a stop.It might run fine for weeks and then it just stalls (It is a 5 speed manual )It starts back immediately when it stalls or if I gas it when It almost stalls it will pick back up,but seems to keep stalling until I turn the key off and start it, then It may run fine for weeks again.
Also the cruise only works intermittantly,It will engage sometimes and work for a few miles then disengage itsself,other times i cant get it to engage at all?
And my final problem is my a/c works great sometimes and then it stops blowing cold all of a sudden.I can turn it on sometimes and it wont cool at all,It has freon in it and sometimes it works and sometimes it doesn't.
Hope SOMEONE has some ideas on this,I've been trying to figure this out for almost 2 years now??????????????It continues to pull code 31 and code 42....Thanks , A.C

[supra saiyan]

You should've looked up what the engine codes mean after pulling them to see what was wrong. They usually point straight to the problem your car is having.

Code 31 is the air flow meter signal (vacuum meter signal), which explains the stalling. Code 42 is the vehicle speed sensor signal, which explains why your cruise control doesn't work properly. Try to find the Toyota Service Repair Manual online, it will give you a step by step process to diagnose why you are getting the engine codes. I think they have them at www.mkiv.com. You might even want to buy the actual book for future references if you do a lot of work yourself. Otherwise, check your afm at your intake, clean it and check the wiring. And check out the speed sensors, look for loose wiring, cracks, and just overall condition.

[supracar1995]

thanks so much for the reply,I had looked up the codes and what they meant but just found out that my car has 2 speed sensors.I had a shop replace a speed sensor on the tranny but unfortunately it looks like the one within the speedometer is the one thats bad.Now from my new information it seems I may have to replace the whole speedometer head to fix this problem?

[supra saiyan]

Check this out:
http://www.supraforums.com/forum/sho...d.php?t=275896
Basically, the solder points behind your odometer get loose and that's where the ECU gets the Vehicle Speed Signal.

[supracar1995]

Thanks again! We are pulling the dash tonight to check the solder points,do you know where the actual speed sensor is located in the dash cluster?
UPDATE:Okay the solder points are all done.....but it's still pulling code 42 but the code 31 is now gone?weird..since tht was the mass airflow code.Got any ideas?
It does seem to run a little stronger,may need to drive it more tommorrow,to make sure it doesn't throw the code again.

[supra saiyan]

[supra saiyan]

Did you reset the ECU after resoldering the points? If the code comes back after resetting the ecu, try this:

On the "ODO and TRIP" harness, run a wire going from #6(pink wire) to #5(blue and red). It is the harness behind your odometer, don't cut any of the wires, just connect them together using another wire.

This will still allow your odometer to keep recording mileage, but will also bypass it so that the Vehicle Speed Sensor signal will always reach the Cruise Control ECU.

[supracar1995]

I had the speed sensor in the transmission replaced first which the mechanic said sorry,that didn't seem to be the problem(expensive guess).So,The computer that we hooked on says
no.1 (backup) speed sensor problem.I hate to sound like a ding dong but do we need to expose the wires and then connect them,and this should do the trick?thanks so much for all your help

[supra saiyan]

Yeah, no cutting, just expose the two wires, use a third wire to connect them, and plug the harness back in.

[supracar1995]

He tried that said the speedo quit working?This is frustrating,Should we look at the speed sensor itself for any damage?What are your thoughts on the elec spark timing is it not tied into the sp. sensor or maybe the coolant temp sensor?Well at least its not pullin the mass air sensor now.when you pull the dash where should we look for the sensor?

[supra saiyan]

Ok, I just did it on my car and this will work.

You will have to cut the pink wire. Tape off the part of the pink wire that goes to the odometer/harness, it is not needed. Then, connect the pink wire (the side going deeper into the dash) to the blue/red wire. That's it, the blue/red wire is not cut, just exposed and tapped into by the pink wire.

The pink wire goes to the cruise control ECU, so basically, you are send the VSS signal from the blue/red wire directly into the cruise control ECU. When done, the odometer and speedometer should still work like normal.

[supracar1995]

What exactly is the pink wire?Is the blue/red wire the no.1 speed sensor wire?I just want to make sure I understand exactly what I'm doing if I'm gonna start cuttin wires.Do you know if speed sensor #2 runs through this somewhere?

[supra saiyan]

If you look at the picture on one of the posts you can follow the vehicle speed signal from the sensor. The blue/red wire carries the vehicle speed signal from the speed sensor in your tranny to the speedometer and to the odometer harness, so yes it comes from the speed sensor. Then the pink wire receives that same signal from the odometer harness, and brings it down to your main ecu/cruise control ecu/power steering ecu. By cutting the pink wire and disconnecting it from the harness, and then tapping it directly to the blue/red wire instead; you are basically bypassing any interference from the odometer board. Doing this does not change anything that the pink, and blue/red wire is meant to do; it just makes a stronger connection so that the vss signal does not get interrupted.

Many Supra owners have done this to make their AEM work. It is also a common fix for cruise control problems. It also fixes some weird shifting on automatic transmissions. All because the signal from the vehicle speed sensor(blue/red wire) is not getting to the ECUs(pink wire) after it enters the odometer circuit board. Doing this makes sure that signal gets where it's supposed to go, but also maintains proper function of the odometer.

[supracar1995]

Thanks for all the info,I will let you know how it goes.You really learn more on thse forums than any shop looking at it.......

[supra saiyan]

If you're having second thoughts on doing the wiring, this will also fix your a/c related problems. The pink wire sends signal to the a/c amplifier as well. Sounds like it will solve all the porblems you're having.