VSS problem

[mirkwood]

Originally Posted by t vago

The resistor golden strip can point to either pin - it does not matter with resistors.



This drawing looks correct. It should solve your problem.



That's a little strange, but as long as your MPGuino works otherwise, it doesn't matter.

Ah okay , thought i was told once that it mattered, maybe that is diodes instead.

Awesome, should be no problem building and installing, already ordered the parts. Signal would be divided by 4, right?

Sometimes i have wondered if mine is some "fake" cheapo copy. But i got it from here, also well known maker i think. But maybe not the official-official MPGuino trip computer - MPGuino



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Hopefully soon i will have happy conclusion to thread , miss having the MPGuino.

And the neat little panel I made can finally replace the ashtray as i intended.

(From 2-3 years ago)

[mirkwood]

Originally Posted by t vago

You could get yourself a 4013 dual D flip-flop CMOS chip. It's a fairly basic piece of 1970s technology

Thanks again, it works now! , finally solved.

The soldering was a bit more tricky than I thought it would be, so tiny, and points so close, but it seems to work at exactly 6500 VSS now, tho still needs some calibration.




Here are the results, I think both times i drove 40km/h.

[ECONORAM]

Originally Posted by mirkwood

Hi

This is not the first time i try to solve this.. had given up, but now saw the MPGuino in the drawer again..

In my first car, a Alfa romeo 155 it worked flawless. Now in my Alfa romeo 75 I cant get a good VSS signal?.

Up until 20-40km/h MPGuino actually shows the speed, but then goes the oppesit way down to Zero beyond that speed??.

I had this problem with my home built VSS. I have a corroplast disc clamped to my driveshaft, with an LED and an IR photosensor reading light pulses through slots in the disc. However, with 4 slots in the disc my MPGuino would do what you described, starting at 35 mph. I covered 2 slots and it worked until 75mph. I only run one slot now, as some highways have an 85mph speed limit. Just need to get a reliable IR sensor installed...

[edit] nice looking panel enclosure!

[t vago]

I made some more modifications to my version of the MPGuino code, and it now easily handles higher frequency VSS signals. An Ecomodder in London is using his ABS wheel speed sensor for his VSS, his pulses per mile setting is near 100000, and he reports no problems with the VSS readings.

[ECONORAM]

So, as an end user of an MPGuino, am I able to load your updated code myself tvago, or do I need some sort of gizmo to help me do that? Or do I just buy a new preloaded chip? Mine is a meelis version...
[edit] will your new code read signals from the ABS or something like the Dodge output speed sensor? The OSS has about 33,000 counts/mile. I couldn't get that to work with my first MPGuino. Don't know if that's because it was a 5v signal, or because it was above the VSS limit...

[t vago]

Originally Posted by ECONORAM

So, as an end user of an MPGuino, am I able to load your updated code myself tvago, or do I need some sort of gizmo to help me do that? Or do I just buy a new preloaded chip? Mine is a meelis version...
[edit] will your new code read signals from the ABS or something like the Dodge output speed sensor? The OSS has about 33,000 counts/mile. I couldn't get that to work with my first MPGuino. Don't know if that's because it was a 5v signal, or because it was above the VSS limit...

The original MPGuino code appears to have a upper speed limit that is due to the amount of time required to transfer all of the raw speed/injector data from the raw measurement trip variable to the instant trip variable. While small, this amount of time was large enough to interfere with intercepting VSS pulses as they occurred. My code bypasses that rather easily. There's a member in London (whom I haven't heard back from in a while, though) who is using his ABS speed sensor with MPGuino, with something like 100K pulses/mile, and he's reported that my code works well for him.

My code should read from your ABS speed sensor. I am going to install an MPGuino into both my Dakota and my Durango, later on this year, to replace the overhead trip computer that I never really liked all that much. I was considering using the VSS output signal from the ABS CAB module, but reading directly off the output speed sensor, on the rear end, might be more accurate.

As for your inquiry? I could send you a replacement chip with my code programmed into it. PM me if you're interested.