MyE28.com

where are u guys connecting or tapping your intake temp sensor?
i know the NA guys are using the stock MAF's intake sensor.
but i am assuming that for FI apps the sensor would be best on the charge side.

second is any one using their stock Coolant sensor with easy therm?

Its not clear if the intate temp wants to be on the charge side. Usally its on the inlet side of your measuring device, so the system properly calculates air mass in. If its in the charge side, that cant happen. The best is to use the main temp sensor on the inlet and a different input for the charge air side as a supplement. This is how WRXs and Mitsu EVOs do it.

I don't believe anyone has gotten far enough here to get to the easytherm. Maybe TCD or PeterF at First Fives have.

RussC

but ms only uses 1 input for intake temperature.
how would u implement 2 sensors?
plus i thought that measuring the temperature of the charge side would be much more accurate given the temp difference between the low and high side.
Plus the measuring device is on the high side, (MAP sensor)

Intake temp must be after the intercooler.
Todd

T_C_D wrote:Intake temp must be after the intercooler.
Todd

And if you're not running an intercooler, after the turbo.

todd, did u tap it into your intake manifold? or somewhere easier that doesn't involve dismounting ?
i have a a2w intercooler,
at first i was going to tap the bottom of the manifold ( like duke's setup ) but its got to come off to do it that way.

Todd has a bung welded onto the output of the intercooler.

You can kind of see it across from the BOV pipe (on the rear of the pipe):


When I spoke to Todd about this, we decided you could just tap the pipe, but that the sensor is not meant to be all the way in the air stream (ie. the threads should not be in the air, just the actual sensor), so it's best to weld on a bung.

T_C_D wrote:Intake temp must be after the intercooler.
Todd

Doh,
Your right, with MS. Since MS uses the temp input differently than the stock ECU. If your using the stock ECU, then no, you don't want it after the IC. I was confussed.

With the stock ECU, if the temp input is after the IC, the temps will most likely be too high,causing the ECU to lean out, to a point. The later ECUs will significantly richen the mixture if the temp gets too high as a "engine savior" mode.

RussC

I'm using the stock coolant temp sensor. I have exact temp/resistance points recorded in VA (I'm in IN till May).

whats the procedure to use the stock sensor?

MS uses a table to characterize the temp input. You just enter the data, or use the third party software to get you the curve to enter.

This info is at the MS site.

RussC

russc wrote:MS uses a table to characterize the temp input. You just enter the data, or use the third party software to get you the curve to enter.

This info is at the MS site.

RussC

You just enter three data points and MS imports the correct table.

my final question:
where are u guys getting your tach sugnal
can i get it off my MSD ignition ?

Does this help you? I don't remember what your setup is.

right know i am going to run fuel only.

what i dont understand is, that i cant just get a tach siganl for megasquirt from the negative coil terminal because it fires , either 3 times or 6 times per revolution.
so how will i get a tach signal from this?

OK,
If fuel only, your still running the 179 ECU, use that tach signal. Right?

It looks like your runing a E34, it has a 60-2 wheel. The MS can get rpm and timing info from that and create a RPM signal output. Like the link Skeen posted. The output drives the MSD unit.

Whats not to understand?

RussC

the part i dont understand:

to my understanding
my tach negative signal has either 3 pulses per on revolution of the crank, or 6 pulses ( if 3 of the sparks to the exhaust stroke pistons are wasted ).

msd takes only the first siganl and ignores the other 5, and sends its 6 pulses evenly.

my confusion is will MS know this?how does MS know only to count the 1st tach signal and ignore the others, to read one revolution of the crank

i thought i was supposed to take the tach output ( made specifically for a tachometer to read RPM ) from the MSD ignition. Not just the negative trigger for the coil.

this is only what i think i am not saying these are facts

Uhmmm,
I guess were not taking about the same thing. Lets not confuse tach signal with ignition signal.

While you can generate a rpm(tach) signal from the ignition signal(the output that fires the spark plugs), why would you want to here. Especially if your doing fuel only?

I don't know the specifics of the MSD unit. But the MSD unit takes the ignition signal and amplifies it to send to the cap/rotor. Other fully featured units can modify it for boost, rev limit etc. Your right, there are 6 ignition pulses for every 2 crank rotations or 1 cam rotation. So, if the MSD has retard capability, it may just trigger on the first pulse, then retard x deg's as programmed by boost or other. Why the MSD would trigger on the first pulses and then ignore the rest and then re-create retard timing seems overly complex. Unless you know the MSD does this. But, why would you want to use the output of the MSD anyway, your interested in the input signal to the MSD, not the coil driver ouput.

With all that said, Im not sure I answered your question. My question is why are you taking the ignition output from the MSD to trigger which input to the MS? I guess I need more detail on what your trying to do???????

I guess your not understanding the MS schematic at the link that Skeen posted.

RussC

i'm taking that MS needs a rpm signal to know when to fire injectors,
how can it get it from the negative coil if the negative terminal is fired more than once for 1 revolution?

Ahhhhggg,
Forget the MSD unit. It does nothing for this. The RPM(tach) signal is a frequency modulated output from the DME in your car. It uses the flywheel teeth(162 on b34) or the 60-2 crank wheel(b35) to generate it. By frequency modulated, it changes frequency with rpm in 1:1 relationship. A 2k rpm generates a 2kHz output signal.

As my earlier post said, use the signal out of the DME! Why are you hung up on using the ignition signal?

RussC

russc wrote:Ahhhhggg,
Forget the MSD unit. It does nothing for this. The RPM(tach) signal is a frequency modulated output from the DME in your car.

As my earlier post said, use the signal out of the DME! Why are you hung up on using the ignition signal?

I'm with Russ on this -- why the confusion? The MSD doesn't simply pull sparks out of its proverbial electronic ass whenever it wants to -- it is triggered by something. What is that something? That something is the same ECU that would be triggering the coil if the MSD were not in the picture. Don't obsess that you must trigger the MegaSquirt from the very same physical location (i.e. the coil negative terminal) that you would use if the MSD were not there. Simply "cut in line" before the MSD gets its trigger signal.

theres is definetly a failure in the communication process.
first off MS= megasquirt not MSD

my question is not MSD related at all!

my simple question is ( taking the MSD out of the picture ):

Megasquirt tach input to run fuel only.( By tach i take it that megasquirt wants to know RPM )

where do i get this input from.
a- negative coil side?
b- do i have to find something that only pulses once per revolution? unlike the negative coil side that pulses more than once per revolution

Papajetta,
You obviously are either trying to piss us off or truley don't understand any of the data weve given already.

So, for the third time. RPM siganl(tach) is one pulse per rev of crankshaft. As the crankshaft varies rotational speed, the one pulse per turn will vary, this varies the frequency(feq modulated). The signal is derived form signal processing the flywheel teeth or front mounted crank sensor. The DME(ECU) does this conversion. This output is engine speed from the DME.

If you can't underatand that paragraph then I highly suggest you get proffesional help with the MS install and programming.

RussC

RUSS, my apologies for pissing u off,
i have figured it out , definetly not by any of the 3 explanations u have given.
if u are going to get pissed off at somebody for not understanding things the way u explain them, just dont post any answers.
By the way this is the professional help for MS, just some egos are too big to be of help.
remember nobody was born knowing everthing.

but my sincere apologies for everyone that ive "pissed off"

Ego, what ego, I answered the question thrice prior.

First one: "It looks like your runing a E34, it has a 60-2 wheel. The MS can get rpm and timing info from that and create a RPM signal output. Like the link Skeen posted. The output drives the MSD unit"

Second: "The RPM(tach) signal is a frequency modulated output from the DME in your car. It uses the flywheel teeth(162 on b34) or the 60-2 crank wheel(b35) to generate it. By frequency modulated, it changes frequency with rpm in 1:1 relationship. A 2k rpm generates a 2kHz output signal. As my earlier post said, use the signal out of the DME!"

Third: "So, for the third time. RPM siganl(tach) is one pulse per rev of crankshaft. As the crankshaft varies rotational speed, the one pulse per turn will vary, this varies the frequency(feq modulated). The signal is derived form signal processing the flywheel teeth or front mounted crank sensor. The DME(ECU) does this conversion. This output is engine speed from the DME"

You can see why Im a little short at this point.

Anyway, too be more specific on help, if you couldn't under stand the prior 2 explanations, then at least get the Bosch Fuel Injection & Engine Management by Probst. Its a great guide and I looked in it once for this thread. There are a couple of mistakes but overall a great reference.

I appologize for my shortness...outburst...whatever.

RussC