I am runnimg haltech e6k with msd dis4 and stock 7m coils setup using waste spark on 3 channels. The car is running great and revs all the way to the haltech set limot. I am having a hard time getting a tach reading on the stock tach. I have used the tach output on the msd box, and I get an accurate reading on the tach at idle and to about 4k rpms. Past that point, the tach drops to 0. Any suggestions would help. I am at a loss.
msd dis4 with stock tach help
- Thread starter trainwreck
- Start date
I don't know if the e6k can do this, but with my ps2000 and e11v2 I was able to use one of the outputs as a "tacho" and then you can configure the rpm signal any way you would like. Just run the output to ig- (instead of the dis-4 tach output) and once configured properly, your factory rpm signal circuit will be restored.
If the e6k is anything like the 8860 tach output, it applies/switches ground, not B+. You can get it to read properly by wiring it up as the 8860 would be wired up to factory tach.
Wire it up to an output set to "Tach out" on the e6k. After that you have to put ignition switched power to the factory tach wire threw a 2.2kohm resistor.
The power will run threw the resistor into the stock tach, when the ground is applied via EMS, its an easier path then threw the tach circuitry and brings the tach wire to 0 volts.
This makes the circuit essentially switched power as opposed to switched ground and should make the stock tach function correctly.
WARNING: FIGURE OUT HOW THE TACH OUTPUT CIRCUIT WORKS AND VERIFY YOUR WIRING BEFORE TURNING ON POWER. IF YOU WIRE IT WRONG YOU COULD/WILL DAMAGE ELECTRICAL COMPONENTS.
IF you cant hook it up threw the EMS, You might need an MSD tach adaptor.
Wire it up to an output set to "Tach out" on the e6k. After that you have to put ignition switched power to the factory tach wire threw a 2.2kohm resistor.
The power will run threw the resistor into the stock tach, when the ground is applied via EMS, its an easier path then threw the tach circuitry and brings the tach wire to 0 volts.
This makes the circuit essentially switched power as opposed to switched ground and should make the stock tach function correctly.
WARNING: FIGURE OUT HOW THE TACH OUTPUT CIRCUIT WORKS AND VERIFY YOUR WIRING BEFORE TURNING ON POWER. IF YOU WIRE IT WRONG YOU COULD/WILL DAMAGE ELECTRICAL COMPONENTS.
IF you cant hook it up threw the EMS, You might need an MSD tach adaptor.
I have tried all sorts of options with the E6k and getting a tach output with no avail. I have come down to trying to use the MSD DIS-4 and using the tach specific output on that alone. As previously stated, the MSD tach output is providing a sufficent signal that will operate the tach from 0 -4k rpms, but from 4k and +, the signal will fall to zero. Would this indicate that I need the MSD tach adapter? (i figured there would be no tach reading at all if the adapter was necessary)
I had these issues using a Wolf ECU and the stock Tach, I ended up taking the Tach to an instrument shop and they added some resistors to dampen the incoming signal to something the Tach was happy to read.
From memory most ECU's output a 5v Square wave signal that's a little too sharp for the Toyota Tach to cope with (did this many years ago so going on my dodgy memory here)
It was a few hundred RPM off though compared to the ECU's software.
From memory most ECU's output a 5v Square wave signal that's a little too sharp for the Toyota Tach to cope with (did this many years ago so going on my dodgy memory here)
It was a few hundred RPM off though compared to the ECU's software.