Methanol injec. help

[jwvess00]

Hi there!

For this design, you would use a knock sensor (not the same one you've got, an additional one) and an ESC module. The ECM is not connected to it in any way. The signal that would normally go to from the ESC module to the ECM is what will drive your injection system. You'll also need to hook up power and ground to it.

ESC module:
Pin A -- unused
Pin B -- 12V
Pin C -- "Knock" signal to your injection system
Pin D -- Ground
Pin E -- wire connected to the knock sensor

You don't want to build anything that tries to use just the knock sensor without the ESC module, since anything you build would have to duplicate the circuitry in the ESC module. That module is essentially a bandpass filter tuned to the same frequency as detonation in your engine. It has some additional circuitry to set the state of pin C (powered or grounded) based on whether it detects knock.

So, you'll connect it as described above, and pin C would be the input to any power-switching circuit you have to run the pump. No ECM required.

[85maro]

Sorry, I got you a bit confused- what I was asking is if the esc 'filters' the output of pin D. Obviously it doesn't so I can't use the esc as a 'filter' or to power the pump because it drops the signal when knock's detected. So what I need to know is can I connect a transistor to the knock sensor to swich the pump's power source?

[jwvess00]

Hi there!

You don't want to build a circuit that directly connects to the knock sensor. The knock sensor is just a microphone -- you need the ESC filter to make any sense of the signal and convert it to a digital output you can use. Your ECM may not use an external ESC module, but that's only because it is built into the ECM itself (as part of the MEMCAL on GenII V6/60s). Without the ESC filter the knock sensor itself is not useful.

Don't get hung-up on the inverted output of the ESC module -- it is very easy to use this output (pin C) to drive a transistor switch circuit. Transistor switch circuits are just as easily designed to take an inverted input (ground=on) as a positive polarity input (power=on).

So, your switching circuit would use the inverted output of pin C to turn the pump on when pin C on the ESC module is low, and off when it is high. This is not difficult for anyone designing the circuit.

[85maro]

Ah, that makes things easier. However using the knock sensor by itself might not be a bad idea. As engine rpm increased valvetrain noise would increase activating the knock sensor, and in effect automatically increasing methanol/water flow as rpm increased. In addition, low rpm vibration could also activate the sensor and roughly increase methanol/water flow around the torque peak. And of course knocking would activate the sensor. I'll try it both ways to see how things work out.