2713ddddavid

iTrader: (1)

This is for icemark (or anyone else who might have the answer) I`m running Megasquirt for fuel and spark. Sometimes when I`m comming to a stop the PS computer gives 2 beeps pauses then 2 beeps and sometimes it will do it a third time then stop. I believe the tach is driven off the trailing spark, since the Megasquirt does not fire the trailing plugs below 800 RPM sometimes the idle will fall below 800 and the tach will drop out for a second or so when coming to a stop. Could this be what causes the 2 beep code from the PS computer? My power steering works fine as far as I can tell. I have also put the stock ECU back in place and I DO NOT get the beep then.

Icemark

Yep, that is the issue.

If the trailing coils get shut down at below 800 RPM (I would think the code should be to fire at the same time as the leading below 800, but I'll address that when I get my megasquirt) then there would be no tach feed to the tach in the dash as well as the power steering computer (and everything else that uses a tach signal).

In an ideal world the trailing would not shut down. In fact I would think there might be increased emssions at idle because of that. Are you sure there is no work around with the Megasquirt operation??? I would think that it would need the trailing coil to work all the way from 500 RPM up minimum.

From a car end, you may have to use a tach filter off of the leading coils and rewire the engine speed signal input for the power steering to that tach filter.

FYI: Tach filter, 4.7K (at 1/4 watt) resistor and 1N4004 diode. "T" off the desired Tach wire, with the bar (cathode side) of the diode facing towards the tach wire. One side of the resistor to 12+ volts switched ignition, the other side "T"d into the non bar (anode) side of the diode. Speed sensor input from the power steering computer also taped onto the non bar (anode) side of the diode. Bare in mind that this maydamage the ECU if wired wrong (I don't know what protection circuits are in a Megasquirt).

Don't know if that will work, but that is what I would try. The tach filter is basicly an isolation and amp circuit for the tach signal.

2713ddddavid

iTrader: (1)

Thanks Icemark. Thats what I thought was going on. As for the trailing not firing below 800 RPMs, I believe I read somwhere that Muythaibxr was going to write or rewrite the firmware so trailing fires below 800. I posted this same question in the Megasquirt forum so I`ll post his answer here when I get it. Just to confirm I have a Megasquirt 1 with version 3.0 PCB. I`m running msns-extra firmware version 029q2. Using Megatune 2.25 for tuning and using easytherm to set up so the MS works with stock sensors.
I look forward to having you get your MS and begine visiting our end of the club.
Thanks again

Icemark

Yeah, I am will be replacing my N333 ECU in my vert with it and a custom engine harness.

Looking forward to plugging in the laptop and programming that way.

2713ddddavid

iTrader: (1)

I actually made an adapter to go between my Megasquirt ad the stock harrness. I bought an S4 ECU off e-Bay and canibalized (sp) the modular plug. With help from guys on the forum and a downloaded copy of the FSM I worked out what I needed as far as pins go. I also had a spare CAS so I did the tooth removal mod on it.I think building the Megasquirt with all the required mods to make it run the 13B was the easy part. Tuning just to get started was more of a challenge. The car runs pretty good so far. My laptop hit the floor about 3 weeks before the car started so I`m at a stand still as far as tuning under load. Its running to get groceries though Anyway, thanks for your wisdom on my beeping, hurry up and get "Squirted" so you can come hang out on our end of the club.