2003 Ford Focus RS - sensors question ?

[stevieturbo]

I'm not sure what the expander position is with an S7, as I believe some of it's I/O's are already salved internally ?

I use the typical ,GT101 sensor ( OE discontinued, but there are alternatives ) on the 8 bolts for my driven wheel speeds. When these where connected directly to my S6 and S8, totally reliable. Not so when connected to the X10.

For front I use a trimmed down Subaru front ( mmm maybe it was a rear, cant recall ) ABS trigger wheel ( 44 teeth but ground down to 11, although that was done as my previous DTA needed less teeth ), again with a GT101 and wired to both my dash and the ecu. Always faultless.

Because of the annoying X10 driven speed spikes, I now use my gearboxes 17 tooth wheel on the output shaft with the OE VR sensor for driven wheel speed directly to the S8.
Again, this works faultless. I do still record and log the individual wheels, but do not use them for any controlling actions.

Find out why you are getting dodgy readings, is it noise ? is it wiring ? is it trigger thresholds ? Is it your sensor ? Are they wired to a correct input for a frequency signal ? a direct input, and not a slaved input ?

On a short drive, log those raw inputs at 1000hz and see how that looks. Not too fast though, 1000hz is no oscilloscope.

[Jackstrath]

Thanks for being the voice of reason steve!

I did look at that but depth was a requirement for me, the GS100502 seemed the logical one for me.

So before i couldnt log raw as i was in pins 33/34 (i think) which are slaves. This didnt help things. Going down the ABS route i moved the PPS to these pins as the need to log raw isnt a thing as the pedal is all set up and working. This free'd up AN03 and AN04 which does allow me to log raw voltage.

Set log to 500 samples on AN03v and AN04v and ran it up on the axel stands. Box went into error but looking at the log i seen the high low voltages so made adjustments to the thresholds, cleared the box of any errors using VCDS and ran another test again. And for the first time i was able to go into neutral and then select a gear again! Ran it back up to 100mph ish and then came back down the box and again was able to select reverse, this time no issues. I dont belive iv fixed it but it defo seems to be working better.

Interestingly the hall sensors i use are 3 wire, now iv left this set to 5v bipolar on input config on the sensor? Wise or not?

Iv attached a log, if you get a second to cast your eyes over it and see what you see? Would be appreciated

[stevieturbo]

higher wheel speeds will be too fast for even 1000Hz, hence waveform won't make sense.

But they do look clean at lower speeds.

I think the fact they don't drop below 2.5v on the log is because you're logging the raw input and the internal pullup messes with it a little.....but would do no harm to set thresholds to say 3v and 4v.
I assume you are set as thermistor ? set as 5v might read from 0-5v instead, although I think if it's an NPN sensor it needs thermistor. My GT101 are set as thermistor.

It's always going to go higher and lower than that in operation.

I don't see any reason why that shouldn't work just fine

[stevieturbo]

Bipolar is for something that will swing both positive and negative. No need at all in this case, as it will only ever be positive. That might be why it appears as never below 2.5

IMO, either thermistor or 5v would be correct.

If it's a powered 5v pnp sensor, then 5v would be fine, in npn that needs a pull down, thermistor would be correct.

Although thermistor and biploar may well behave the same in this case in terms of how it works for you.

[Jackstrath]

Yeh i have the Low set to 2.75v and High to 4v

They are currently set as 5v Bipolar but i will change it to 5v and see how they log and if it looks clean still.
They have a 5v power supply going to each sensor, yes.

So just so i can get a better understanding, say sensor reads 2.5v low and 4.8v high, are you best having the thresholds set tight to these or larger gap? IE tight would be low 2.6v and high 4.7v and large would be low 3v and high 4v?

[stevieturbo]

no reason why you couldn't set them at say 4.0 and 4.1

If it goes above 4.1, it's a valid trigger, if it goes below 4.0, it's a valid trigger.

Hall sensors are simple like that though, they have more defined non variable thresholds.

If there was say some noise in the middle you could to closer to the extremes of voltage like 2.6 and 4.7, but then if for whatever reason you fell short, it might ignore that tooth.

So I'd be staying closer to the middle, but really doesn't matter so much. If it works it works.

And turn filters off, mine never worked well as speed signals with it turned on, although I suspect they're off anyway

[Jackstrath]

So did a few more runs on the axel stands and got some confidence that if the car did jam in neutral, armed with the laptop i could get it moving again.

It went ok, no massive issues, shifts are a little meh but until its all set up and i run at least an adaption on the box.

Box did again show the speedo input error;
17106 - Transmission Output Speed Sensor (G195)
P0722 - 000 - No Signal - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 255
Reset counter: 39
Time Indication: 0

18201 - Transmission Output Speed Sensor 2 (G196)
P1793 - 000 - No Signal - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 0
Fault Frequency: 255
Reset counter: 39
Time Indication: 0

Interestingly now being able to see the logs, i can see at roughly time stamp 19:08:44.718 there is a long pause in the readings. Guess thats where ill need to look at first but its a bit weird that both sensors stop reading. I thought it was maybe play in the wheel bearings (brand new might i add) causing the bell bolts to move away but id only expect to see that on one sensor not both?

And seeing as youve helped me to no end steve feel its only fair you get to see the car running first!

https://www.youtube.com/watch?v=wexyc4X3CnI

[stevieturbo]

oddly yes there do appear to be some dropouts.

really, considering it is both inputs, it would have to be either a 5v or signal ground issue ?

Nothing else could stop both triggers at exactly the same time. Do they both share the same 5v and signal ground wire, and does anything else you can look at too ?

But I also see you've dropped the logging rate on the raw inputs.

Keep it high, 1000Hz if possible. Although I doubt such a long dropout is due to logging rates.

Perhaps more strangely, is speed for both RR and RL ( rear if this is what you're using here ) still shows a speed reading. I'm not sure what scenario is possible where the signal drops out, but the speed reading endures, especially for such a long period.

[Jackstrath]

So they have there own 5v (both sensors with nothing else on it)
They do share the same ground as the Brake pressure sensor and the IAT sensor. Typical i havnt logged the BPS but as its on a slave1 input im not sure i can log raw voltage on it.... Il defo add the read out to the log now tho just to see if it relates. IAT looks fine otherwise.

I have the spike detection limit set to 10 and decrement interval set to 3 but nothing i can see there causing an issue? Is it worth changing the vehicle speed averaging filter?

Il put it back to 1000hz but was scared it would fill up the log quick!

Yes speed is on the rear (part of the DSG control needs the inputs on there, assuming as it was developed from a lotus, rear engine, rwd) but like you say the speed reading dosent drop but wondering again if that to do with the averaging filter?

Have another log from a very slow test drive and it does it again at 18:20:13.539

Interestingly, Roman, popped a comment on my facebook post on the syvecs group and said you can put MR sensors into the S7 but the ECU might need to go to Syvecs to get modded, another option to look at, but iv asked the question if the ABS system will still work.

Raining today so no logs for today!

[stevieturbo]

you can log brake pressure fine, you just can't log the raw analogue voltage of slaves.

If you think you do not have enough logging memory, when you have the laptop hooked up, you can stream the data and log direct to the laptop instead of the ecu, so you have almost infinite memory, or as much space as the laptop allows.

You are not seeing any spikes, so I think that is irrelevant

I use 1 tooth per reading, no filters... vehicle speed averaging filter would only be how it acquires vehicle speed from what you have set for the individual speeds it derives vehicle speed from. I use 70ms here, and vehicle speed for me is an undriven wheel speed, FL.