Speed Sensor for 1992 Lancer 1.8 Automatic

What is the model of your transmission? What other cars use that transmission? Try looking for those vehicles in a junk yard. That sensor would not seem so expensive if you had not wasted your money on that computer.

The gearbox carries the number F4A222MRF3 - underneath is MC7196.

No money was wasted on the computer, it came from a wrecked car - FOR FREE, ok?

In a Mitsubishi 1992 CC Lancer 1.8 Automatic, the electric overdrive drops back unexpectedly when hot - the gearbox has new fluid - the computer has been changed with no difference in behaviour - "Experts" say the cause is a faulty speed sensor feeding engine revs to the gearbox computer.

Unless I am mistaken the OBD II controls on all newer vehicles also look at loss of engine vacuum (ie engine loading) as a signal/reason to unlock the torque converter. Has that been checked?

Also; high temperature issues usually indicate poor (loose) or contaminated, high resistance electrical connections either at the sensor or at the ECU module.

The vehicle speed sensor is a relatively cheap "Hall-Effect" type sensor mounted directly on the tail shaft of the tranny and shouldn't have anything to do with engine revs. They seldom fail but can become contaminated with metal filings and suffer intermittent failure and/or poor feedback signal strength and/or integrity.

The engine speed sensor is a similar type pickup that monitors the crankshaft revs and is critical to engine timing and cylinder spark delivery. If it is completely bad, the engine wouldn't run well or not at all. However, if is just dirty the signal would be weak and cause intermittent problems at high temperatures or when vibrated excessively. It is significantly more expensive than the vehicle speed sensor. In a lot of cases this sensor gets contaminated with metal filings suspended in the engine oil and only needs to be cleaned. It is mounted on the front side of the engine near the crankshaft (dampner) pulley. Locate the sensor, carefully remove it, wipe the sensor clean, and re-install it. The electrical connector on the sensor also gets contaminated with oil and dirt because of it's location and many times will fail at high temperatures due to the high resistance connection interferring with the signal. Make sure it gets cleaned as well.

If changing these components does not help, the issue is most likely that the torque converter is failing due to excessive mechanical clearances in the vanes caused by high mileage.

Here in the USA there are many auto parts stores such as Autozone, Checker, NAPA, etc, that import aftermarket manufactured components and sell them at a reasonable price. I called some of these stores and they do not show a Mitsubishi Lancer for 1992. If you will send me the vehicle identification number, engine number, and any other pertinent vehicle information you might have, I will attempt to locate the

part(s) you need. My email is: james_morris@fmi.com or kalina@aznex.net

Unless I am mistaken the OBD II controls on all newer vehicles also look at loss of engine vacuum (ie engine loading) as a signal/reason to unlock the torque converter. Has that been checked?

Yes

The vehicle speed sensor is a relatively cheap "Hall-Effect" type sensor mounted directly on the tail shaft of the tranny and shouldn't have anything to do with engine revs. They seldom fail but can become contaminated with metal filings and suffer intermittent failure and/or poor feedback signal strength and/or integrity.

All speed sensors on the gearbox have been checked and cleaned - No change

.....they do not show a Mitsubishi Lancer for 1992. If you will send me the vehicle identification number, engine number, and any other pertinent vehicle information you might have, I will attempt to locate the

VIN:- JHFCC6H41NJ002810

Chassis:-JHFCC6H41NJ002810

Body:- FSRCB5APU00441

Gearbox:- F4A222MRF3, over MC7196

Computer number:- ELC93SMFMALK1 over MD753824 over G1T12579E over 2724

These numbers are all centered on a small stick-on label about 4cm x 1.5 cm ( 1.375" x 0.75" approx.)

Kilometers done:- 233,075

Hope this helps,

thanks very much

GC