Megasquirt Support Forum (MSEXTRA)

Haven't read the whole thread but...

Watch out for the situation where your boost vs. TPS target produces a situation where the pressure before the TB is greater than after the TB. More likely at higher RPM.

Nice. "Cycle average" takes several samples at the same points, per engine cycle and averages them?

So say, 8 points averaged between valve opening events should give an accurate facsimile of "true" MAP.

IRTB's would be a special case - it may need a MAP sensor for each cylinder, and the min reading per engine cycle may be the most accurate.

Another thread resuscitation post. Someone had mentioned "synchronous" sampling earlier in this thread, where the analog signals are sampled at some quiet point, e.g. just before any injectors and coils are turned on or off. I work for an IC company whose IC's often have pins that are sens...

I built a circuit that does closed loop control of wastegate can pressure, using a gauge pressure sensor tapped into the wastegate hose between the boost solenoid and the can. The output from the ECU PID loop is now target wastegate can pressure instead of solenoid duty. Made boost control faster. S...

.. which would be proportional to to V.E. x RPM. Such a number would be proportional to power. This would be used for correction curves that should be proportional to power such as: - low airflow MAT correction ... (e.g. the Autronic has a correction factor that blends the MAT reading with CLT at lo...

First and biggest advantage is ease of tuning, especially initially. It can reduce screwups. The VE x RPM table actually means something physical in the engine. This is a function of the cams, intake and exhaust resonance tuning. If tuned correctly the VE x RPM table should resemble the expected tor...

I would go at least with a 220 uF electrolytic.

My point re: gslender's oversampling, is that oversampling (relative to the orig sampling rate) in the case of MAP works because the old sampling rate was slower than the actual signal changes. With TPS, oversampling will ALSO help in the presence of noise because it gives a better picture of what i...

One mod I would suggest for the above diagram would be to either use the same block connection for the battery strap or a comment to use battery ground as ground if possible. Totally unnecessary. The battery (-) terminal is no more a "ground" than the chassis or engine block are. It's all...

That's a nice diagram but I would modify it thusly: 1) Also use shielded cable for the O2 sensor (which arguably needs it more) 2) Shield is better grounded to block or head (and again at only one end), rather than at MS2 signal ground. Actually none of my 30 yr old harness is shielded except crank...

Further I have to repeat that as long as sensor ground wire does not carry current, there should not be a issue with noise or voltage offset on it. But if you connect the sensor ground wire to vehicle, you are asking it to help sink current from the MS box and it is no longer a reference, but a con...

I'm concerned that we are causing users to expend a lot of energy on possibly redesigning the MS board GregG and Gslender have shown that a 10x(?) oversampling ant 10 pt running average helps a lot for their idle. Some others have shown great improvements with shorting out the polyfuse. All the abo...

It's just that I was told elsewhere that the polyfuse sat between signal gnd and power gnd. In any case, we've been discussing principles and not just specifics. That's not "speculation". That is why you should look at the schematics yourself. I did and I couldn't find the polyfuses at th...

0.1 uF is way too small. The filter can ring given the right load current step.

The inductor in the return leg will only work if the ground on the left and right of it are isolated.

It's just that I was told elsewhere that the polyfuse sat between signal gnd and power gnd.
In any case, we've been discussing principles and not just specifics. That's not "speculation".

Peter Florance wrote:I wonder if it would be more efficient for you to get your hands on a V3 board instead of working by remote?

Yes but I don't have one. (yet)

Another point that has pointed out was adding capacitance after polyfuse, yes i tested that, whit normal electrolyts (good quality Panasonic FM series and also Sanyo´s OS-CON´s that have wery low ESR at wide freq.range) but none of those worked as replacing that polyfuse by normal fuse. So i must s...

Ideally, If your mainboards ground planes were split up properly, and/or if you have all external power drivers for coils/injectors, the MAP/TPS/etc sensors go to their own dedicated signal ground pin(s). Analog circuitry and the A/D have to be on the same ground plane. The high current stuff can b...

Further I have to repeat that as long as sensor ground wire does not carry current, there should not be a issue with noise or voltage offset on it. But if you connect the sensor ground wire to vehicle, you are asking it to help sink current from the MS box and it is no longer a reference, but a con...