Frequently Asked Questions.


What do the values of the SMT-FT's ignition map actually mean on the engine's timing?

The SMT8-FT doesn't know what the engine's timing is but it can advance or retard it. Positive values in the ignition map will advance the timing and negative values will retard the timing. Any value used will be added or subtracted from the base ignition timing. Zero entry will be the stock or base timing.

Where should the SMT8-FT Fuel Tuner be fitted?

It should be fitted inside the cab if possible, or in the engine bay out of direct heat caused by the cooling fan.

What wires need to be connected for the unit to work?

The injectors are unplugged and the SMT8-FT is plugged in between . Then fit the earth connections for the basic installation. For the more advanced installation the ignition and MAP sensor can be modified.

Can SMT8-FT modify the timing?

The SMT8-FT was designed as a plug and play fuel tuner with additional functions. Should you need to do timing, the SMT8-FT unit does have this capability.

Can the 4-cylinder unit work on an odd cylinder engine?

Yes it can. It will even work on a single cylinder engine.

Can I fine tune the SMT8-FT Fuel Tuner unit?

Yes you can. The unit has a map of 384 load sites, and you will however have to change the wiring on the potentiometer so that it can be wired to the TPS or load sensor.

My laptop has no RS232 connector. How do I connect to the SMT8-FT?

The only way to communicate is with the use of a USB prolific converter.

I have connected the USB prolific converter but cannot connect to the SMT8-FT?

Verify in Windows, in the Device Manager, under Com ports that the converter has been assigned to COM port 1. If not, go into the advanced setting and reset it to COM port 1.

How does the SMT8-FT unit communicate?

The unit uses RS232 to communicate.

I have changed the Com Port setting but the unit still does not communicate?

Check in the LetRipp software under Tools, Communication Setup, that it is set to RS232-115K and that COM 1 has been selected.

The green cursor is in the middle of the map and not in the left column as it should be?

The TPS scale has not been set up correctly. By pressing : "Shift F7" the TPS config map will open.

I lost my communications cable, where can I get a replacement?

The RS232 cable is a generic and can be bought from any computer store.

What is the maximum fuel that I can add or remove?

The SMT8-FT works in percentage that is adds or removes up to a max of 50%.

My RPM is double that of the rev counter. How do I get the correct RPM?

Double the edges per turn in the system setup. If you are getting the RPM from the injection signal then check in the "Shift F2" that the batch setting has not been enabled.

I have teed onto the crank sensor with pin 6 of 12, the +crank input, but I don't see any RPM in the LetRipp software when the engine is idling?

Use the system definition and turn the high crank level on or off.

My crank signal is on one wire. How do I know if it is a magnetic or digital signal?

Easiest way is to check the signal with an oscilloscope, but not many people or workshops have this tool. Check the actual sensor; if there are two insulated wires and one screen wire (exposed wire), then the signal is magnetic. If there are three insulated wires then one wire will be 5 volts, one will be ground; the remaining wire is the digital signal.

Perfect Power uses the term balanced crank signals. What does this mean?

This term means that there are two magnetic signals, which are exactly opposite each other at all times.

What does analog mean?

A circuit or sensor that ranges from 0-5 volts.

I have wired my airflow meter into the analog 1 circuit, but now my engine doesn't start.

Firstly, check the wiring. The wire from the meter must go to pin 7/12 and the return wire to the ecu must be pin 5/10. Secondly, check the parameters for analog 1. The upper limit should be 5.00, the lower limit should be 0.00 and the ±% should be 0.00. Thirdly, check the analog 1 map and side tables, the main map and the engine and air temperature maps should be zero, the AMP side map should be one. Lastly, check the protection map, all fields should be zero.