Vehicle speed sensor

[Simon123]

Corolla 93, 1.3i, 4 cylinder, 4e-fe

Dear Friends,

I recently bought my first corolla, since I had a limited budget I was forced to buy a corolla without a RPM meter,
I know one could just go by the sound of the engine, but I am concentrating on the road.

Being an electronic engineer I am confident I can build one cheaper than
one of the shelf

A) In a repair manual it says there is a Vehicle speed sensor connected to the engine, anyone know how this works?, output signal in relation to RPM's


B) What is the normal RPM, when the engine is idleing?

C) roughly what RPM should one change gears i.e 1-2, 2-3 etc..?

D) Could I just rip a tachometer from a corolla which has the same engine type, any sugesstions? any ideas?

Cheers

Simon

[SpinnerCee]

VSS has nothing to do with RPM -- VSS is connected to the final drive [ie the drive shaft], so it's speed matches the speed of the [front] drive wheels -- notice gear AND RPM influence VSS.

I think 4aFE toyota engines need to be shifted before 4000 RPM --- where the redline is around 5500 -- I wouldn't try to make a tach on your own [however I think you measure AV volts], especially one that is based upon VSS [Vehicle Speed Sensor] input == the '93 has a crank trigger to signal RPM. The Speedo is connected directly to the VSS, so it does not indicate gear or RPM althoiugh it is "determined" by both.

Get your Chilton's and check it out, but a donor tach [gauge cluster] may give you more ideas -- It may or may not be a simple swap, especially if the model year is different on the donor.

Usually a tach port can be found on the DLC inside the engine bay -- there may also be a takeoff on the steering column harness inside the car as well -- it depends upon if a tach was ever offered, and how common the wiring harness is between dash options.