What's up with my TPS and MAP?????

[bcool]

'm afraid my anolog to digital converter might be dead or it might be something I need to change.I know that the TPS and MAP share a common 5v reference signal. When I power up the board on megatune the TPS and the MAP range are both at 100% and they slowly drop down consistently together until they get to about here?

[dnb]

First of all, check that you have alphaN turned off.  (This effectively makes MAP into a scaled version of TPS)  The settings are lurking somewhere at the bottom of the settings menu - something like "AlphaN blending".  They should be set to high numbers.

Then check the grounding, suppy and resistance of the TPS.  I've not seen A to D failures in VEMS where the signal drifts around.  It normally gets stuck somewhere and just stays there.  It's usually something on the analog side playing up - perhaps the 5v regulator if the above don't work.

[bcool]

My settings


The 3rd pin from the right on the MAP shows a solid 4.94 and doesn't change
**edit**
AH HA!
I'm getting no voltage at all on pin 29 which is supposed to be the 5v out for the tps.

[bcool]

So this basically means that i'm now stumped

[rob@vems.co.uk]

Is this a system you've built yourself?  If so check that the resistor between pin 28 and pin 29 is in place.  The TPS feed has a resistor to make it a 'weak' signal.

I've been known to use Pin28 to feed all the required +5V signals.

[bcool]

Yes this is a V3.2 board that i assembled.

It looks like theres nothing there. Since i've already got it pinned in on the connector i'm assuming i can just bridge the two terminals to give my TPS the 5V signal it needs?

Oh, I tried re-uploading the firmware and now get this.

I redid the process step by step with the 12x12 version and i still get the exact same thing. Man i'm on a roll tonight.

[rob@vems.co.uk]

Don't bridge it with anything other than a resistor of the right size. The one on a board I have here says "271" on it.

Stick with the 12x12 for your initial tests mate, start simple and add complexity.
You'll find that the 12x12 is pretty much all you need except on a small cammy engine where you might need some additional interpolation at the low end.

[bcool]

Ummm same exact deal with the 12x12. You know....Maybe this has something to do with the map sensor itself. It does say that theres a difference in kPa values. Hrmmmm




And just to verify what we're talking about Is there only 1 resistor used between them or is there two?

[dnb]

Depending on the application, there's different MAP sensors and different scaling factors.  These do need to be matched in the INI file and the VEMS itself.  You need to look in the ProfileActivation folder and make sure the correct boost profile is selected.

It is quite likely that the version of Megatune and the Firmware in your VEMS are not compatible - especially if you have recently downloaded a new MT and the ECU is a 3.2.  This means you should reflash the firmware in the VEMS.  Rob has written some good instructions for doing this (available in the "software" forum) , so I'll not go into it here.  This should clear up the MT error message.

I'll let Rob deal with the soldering issue since I don't have schematics to hand.

[rob@vems.co.uk]

And just to verify what we're talking about Is there only 1 resistor used between them or is there two?

One resistor on the bottom pads, this pulls the pin up to 5v through the resistor.  The top pads would pull the pin down to ground.

Ignore the 2,4 error, go into the basic settings and correct the boost option to suit what you're running.
I think 4 is insane boost.   You want high boost which will report 2,2

Rob

[bcool]

Weird i dont know how that got changed to the insane setting. I switched it back to default and all is well now.

So i'm assuming just soldier it up in this configuration?

[bcool]

K got that on now i'm getting a clean 4.93V

Alright down to the original question....what the hell is up with the TPS and MAP on my megatune.

[rob@vems.co.uk]

When I see that sort of behaviour its as if the sensors are not connected.  Follow the voltages into the A2D converter and try pulling up or down the lines and monitor the voltage and behaviour of the MegaTune dials.

[bcool]

OK now this is weird. I have it connected on the car now. I dont see the TPS or MAP dropping down from the 255kPa value and the 100% tps value, so they stay stable there, but what is weird is when i i apply throttle about half way through my throttle position range the TPS AND the MAP both start dropping their values at a consistent rate together until my foot is to the floor 

[bcool]

Here's the video of said action:

http://myweb.cableone.net/mjbless/vems/tps.mpg