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SMT6 | Frequently Asked Questions


Frequently Asked Questions.


What do the values of the SMT6's ignition map actually mean on the engine's timing?

The SMT6 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.


Can I use your SMT6 software to tune work engineering EMS-1 using Windows 7? Is it compatible?

The SMT6 software is designed to work with the SMT6 unit only. It can not interface with other control systems. The SMT6 software is compatible with Windows 7. If you need to tune your Work engineering EMS-1 (SMT6D unit) you will need their software or we can provide generic SMT6D software which will zero to your existing tune.

Is it possible to get SMT6 wiring diagrams and software? And can SMT6 support turbo application?

What type of turbo application? The manual and software for the SMT6 is available on the Perfect Power website. You can find the wiring diagram in the SMT6 manual and the software download section.
 I have a Proton Gen2 1.6, with a bolt-on turbo. Before this, my car was running N/A. I am using the SMT6 piggy-back unit. The SMT6 will not be able to do the timing retard on the Gen2, but can do the extra injector and fueling control.

I've had the SMT6 for three years on the BMW e30 325i and recently it has been giving me a problem reading "AFR input" which shows a constant voltage of 0.57V when the Bosch KTS working properly. Is there any way to fix this?

If it has been reading the right lambda reading for years it might not be a SMT fault; it could be a wiring fault. If the wiring is good you can check the lambda circuit by feeding an external 0.1V into the lambda input, which is a brown/black wire. And then check that the SMT6 software shows 0.1V.

Does the new SMT6 program work with the old one and how does that work? I have an older SMT6 and the new download is what I mean. Is it for that?

The old SMT6 with aluminium tabs uses software version V2.6.11. The new SMT6 with the USB Connection uses software version V3.1.13.

I have a 1990 BMW E34 535i 3.5L 5 Speed TCD Turbo (Turbo Charger Dynamics). I have the SMT6 and I want to use coil packs. Instead of the cap and rotor, tired of it going bad. I also have MSD 6 AL. Can you please tell me how to go about it? And what coils to use and so on.

Unfortunately the SMT6 isn't able to generate a coil signal. An XMS5 is the better/right choice. We also had a look at the MSD manual and it states that the version you have is not meant for distributor less coil systems. From our side we can recommend a VW VR6 coil pack and a XMS5B system with a 4 channel ignition amplifier to replace the cap and rotor.

Can you guys please help me to install my SMT6. I bought it second hand, just need to connect wires and take it to my dyno. I basically just need (the Opel Corsa b codes and the wires). I already have the SMT6 manual from your website.

The wiring diagrams for the SMT6 are posted on the Perfect Power website. If you are unable to find them please email This email address is being protected from spambots. You need JavaScript enabled to view it..

When I install the SMT6 software the program always displays this error : "an error occurred while registering the file". What should I do?

If it is a "ocx" file then don't worry. On some computers this is normal.

I am using a SMT6. Can SMT6 perform launch control/rev limiting with a trigger? If it can, can you show me how to wire it?

We don't supply piggybacks and launch control/rev limiting.

Does SMT6 have a Rev Limiter?

SMT6 isn't really designed to interfere with rev limits so we don't support rev limiting or removal of rev limits.

The engine temperature is bouncing up and down in the side table, I have not connected the SMT6 piggy-back to my engine temperature sensor, and how do I stop this?

Ground the SMT6 engine temperature input, it is pin 11 the green/yellow wire.

The SMT6 has an aluminium tab with a hole punched in it. Must I mount the SMT6 through this hole?

You can if you want to. The tab is a heat sink for the extra injector driver. If you are using your SMT6 to drive injectors, boost solenoids or nitrous and the tab is getting warm then mount the SMT6 to a larger piece of aluminium to help dissipate the heat build up.

I have a wiring diagram for my car but out of the 22 SMT6 wires I only use 7 wires. Why?

Most installations use 7 wires, check the full list of the other wires in the SMT6 Developers Manual.

Is the SMT6 piggy-back waterproof?

The SMT6 is splash proof but will not survive being immersed in water as the connector is not water tight.

Which wire should I start the installation of the SMT6 piggy-back with and which wires should follow there after?

+12 Volts switched power. Earth/ground. Throttle Position. Airflow Meter or manifold pressure sensor. Lambda Sensor. Crank Sensor. This is the recommended order in which to install. Install each connection and then verify that the engine operates normally. If at any step the engine does not operate normally then the troubleshooting on the installation is much easier as you know which connection to concentrate on.

Can the SMT6 work with wide band lambda and narrow band lambda probes?

The SMT6 can work with narrow band probes only. The newer SMT8 piggy-back range can work with both lambda probes.

Can the SMT6 alter a road speed governor?

Yes, this is a common application for the SMT6

How many analog channels can the SMT6 modify?

1 x 0-5V channel

Can the SMT6 compensate for engine and air temperature changes?

Yes, but the SMT6 has one input for a temperature sensor. You must decide which one to use.

Can I use the SMT6 to remove my air flow meter and use a MAP sensor instead?

This can be done but requires extensive tuning. We rather recommend using a less restrictive air flow meter and an SMT6 to fine tune it.

Can I use the SMT6 in conjunction with my race prepped EPROM?

Yes, the SMT6 will work and can be tuned in real time.

I have connected the SMT6 brown wire onto the throttle position signal but the software doesn't show any value. I know that I have the right TPS wire as I measured it with my voltmeter and the voltage increases as the throttle is opened.

Firstly, check that you have not used the SMT6's brown/black wire; the right SMT6 TPS wire is brown and is pin number 7. Secondly, you will have to calibrate the TPS voltage using the SMT6. Refer to the SMT6 Developers Manual.

What does tune in real time mean?

As you enter values in the tuning maps the engine will react immediately. No waiting around or restarting the engine to see the effect of your tuning. This makes the tuning time very fast.

My SMT6 shows my throttle going from the left of the tuning maps to the right as I push the throttle. My friend's SMT6 shows from the right to the left on his car. Have I done something wrong in the setup?

No, some throttle position sensors work from 0-5 volts like yours and other TPS sensors work from 5-0 volts like your friend's. Your SMT6 will be tuned from left to right while your friend's SMT6 will be tuned from right to left. The SMT8 has a check box for the TPS so every time you can setup the software to show the cursor going from left to right or vice versa if you prefer to tune your car in this manner.

In the DOS commands help for calibrating a map sensor it says "AL p dis [cnt] lower calibration". Can you explain this in more detail?

The "AL" is the amp low scale. The "p" is the position in the table you want to calibrate. The "dis" is what you want displayed at that position. The [cnt] is the voltage at that position converted into counts. Each volt represents 51 counts so if you wanted to calibrate position 2 and the voltage at 0.3 pressure is 0.5 volts then the example will be as follows : AL 2 0.3 25.

Some say that the Perfect Power SMT5 has a memory problem. Does the Perfect Power SMT6 have this problem?

The SMT5 did have a memory problem, the fix is to wire it to permanent battery power. The SMT6 doesn't have any memory problems.

How is the engine temperature scale setup in the SMT6 piggy-back?

The dos commands are used for this. Refer to the SMT6 Developers Manual.

How is the AMP scale setup?

The dos commands are used for this. Refer to the SMT6 Developers Manual.

Does the SMT6 have two tuning maps?

Yes, the SMT6 has two tuning maps. One can be for performance, the other for economy.

How many outputs are there for injectors or other devices?

Two. 1 high power output for injectors or nos and 1 low power output for a relay.

How much power can I expect to gain from fitting the SMT6 to my car?

Power figures vary from car to car but if the SMT6 is installed and tuned properly you can expect the maximum performance from your engine.

Is the SMT6 the right choice for my car?

The SMT6 is a very advanced piggy-back with many features. You need to decide what you need out of the piggy-back and see if the SMT6 will cover all your needs.

If I am not using the engine temperature input, what should I do in the maps?

Make the engine temp side maps zero.

When I try connecting to my SMT6 the software says "runtime error 6". If I click "okay" the software will shut down. Why is this happening?

There is an invalid entry in the global settings of your SMT6. Refer to the reset application note to reset your SMT6 to factory default. Take note that this will over-ride the existing map!

My laptop doesn't have an RS232 port. What must I do?

Use a prolific to serial converter which has 16 megs of buffer space or more. Also set the converter to com port 1, 2, 3 or 4 and then set the SMT6 com port to the same as the converter.

I have wired my extra injector but it is very hard to tune.

Turn the global setting "nox inject" OFF

I have turbocharged my engine and I am going to use an extra injector for the fuel needed when boosting. Do I need to fit a pressure sensor and wire it to my SMT6?

Yes, this is highly recommended. Make sure you use a pressure sensor that can read the range of boost you want to run at. With this setup you will mostly tune the extra injector when in boost and not when cruising.

My car struggles to start if the battery is slightly flat. It actually feels like the ignition timing is set very advanced. Can the SMT6 cause this?

The battery voltage is dropping below 8 volts under cranking and the SMT6 is switching off. Replace your battery or use a battery charger. The ignition circuit can also be bypassed under cranking if the problem persists.

My crank signal has two missing teeth. Which mode must I use?

Mode 1. Missing Tooth.

My crank signal has 1 missing tooth. Which mode must I use?

Mode 1. Missing tooth, the system config setting for 1 missing tooth must also be "on".

My AFM voltage goes above 5 volts. Can the SMT6 be used on a high voltage analog signal like this?

Yes, the SMT6 can work up to 9 volts on its analog output.

When I use the SMT6 to control the boost on my turbo car the engine light keeps coming on and the error code is about the N75 valve. How do I fix this?

The ECU was controlling the N75 valve, but now you have cut the wire to the N75 valve so the SMT6 can control it directly. What you need to do is wire a 1 KOhm quarter watt resistor onto the ECU wire and onto switched 12 volts.

What wires do I use to do boost control?

SMT6 Pin9 connect to chassis. SMT6 Pin22 connect to the negative side of the N75 valve.

What must I setup in the software for boost control?

Set the global setting "nox inject" to ON.

Which tuning map do I use for boost control?

The F2 injection map