Had a couple of hours tonight in the garage with my new picoscope and my car, its a 1990 daihatsu 3 cylinder 660CC turbo petrol! I worked my way through the pico diagnostics looking which was great.
I then looked at the map sensor which looked ok. Then i looked at number 1 injector..had a go with the measuring rulers

Next i looked at the oxygen sensor, on this engine its just got a single wire mixture control sensor. I tried various time scales but couldnt get it to display a decent waveform. I was using the battery negative as a earth.

Any help or guidance would be great.

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Wonderful tool copy & paste  [smiley=disimulo.gif]

What type of sensor is this ' mixture control ' sensor & what was the fueling status ?

Robski wrote on Jan 25^th, 2012 at 12:55pm:

Wonderful tool copy & paste  [smiley=disimulo.gif] What type of sensor is this ' mixture control ' sensor & what was the fueling status ?

I'd thought i would try my luck over the pond on here as it seemed a little quiet in england.
My engine just has the one oxygen sensor located ontop of the CAT after the turbo. I refer to it as a mixture control sensor...
It has a single black wire coming from it. The engine was fully warmed up and ticking over at idle.I'm still using the presets as its all very new to me, but i couldnt seem to make any sense of the displayed waveform.
To be honest i suspect that i was getting quite a bit of noise and interferance as the connector for the sensor is right next to COP 3.

Russ

GRUSS wrote on Jan 25^th, 2012 at 1:07pm:

It has a single black wire coming from it.

How did you connect to this single black wire?

Could you connect at the engine control module so as to get away from that COP.

If the captured wave stays low rev the engine to see if the voltage swings up to close to 1 volt or add propane to enrich the mixture.

I back probed the connector and connected the earth lead to the negative side of the battery. I need to try the low pass filter as I've seen it in action on the videos. Connecting at the Ecu would be tricky as its buried up behind the dash.
Are my screen settings ok?
I wanted to check the sensor as my mpg has gone down. I did try revving the engine but all I got was a mess on the screen.
The preset for the map sensor was spot on though

GRUSS wrote on Jan 26^th, 2012 at 12:02am:

I back probed the connector and connected the earth lead to the negative side of the battery.

GRUSS wrote on Jan 26^th, 2012 at 12:02am:

I wanted to check the sensor as my mpg has gone down

Well if its a good connection your o2 sensor is reading  200mV or so then that sensor is telling your ECU to add fuel.

Now if you are sure you cant raise that voltage by adding fuel, like reving it or adding propane then it looks like a dead o2 sensor.

I like the propane bottle to shoot a sniff into the air box and also around the intake and hoses.

I've just got in and loaded the 02 waveform up on the laptop and tried the low pass filtering.. what a difference!
Whats the difference between the resolution enhancement and the filter, i presume the filter is the favoured choice as any more than 14 bit (12 bit default) then the vertical lines start to slope. i read this was a side effect of using the resoultion feature.
I will have to connect the pico back upto to the engine and carry out some more tests on the o2 sensor now i'm armed with this new info!
I have a wideband innovative LC-1 sensor and controller on the exhaust as well,its a standalone unit not connected to the ecu. I have a fuel controller which works on the map signal wire so i can adjust the AFR's etc. During normal cruising i'm getting a steady 14.7:1 so the o2 sensor must be doing something, i just suspected it was a little lazy when the engine was cold as it has no heating element..

When i attach files can you guys load them up in pico and make changes or can i only do this?

Does my injector waveform look ok then?

Thanks

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Here's you SW-O2S with a filter.

To get this type O2 to respond, just rev it up and watch the pattern.  My method was WFO and back to idle similar to a throttle snap test  [smiley=thumbsup2.gif]

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Thanks for that!
How did you turn the color red? And is that just with a 1khz low pass filter?

GRUSS wrote on Jan 26^th, 2012 at 11:23am:

I have a wideband innovative LC-1 sensor and controller on the exhaust as well,its a standalone unit not connected to the ecu

So you modified the vehicle?

Is this the site that would apply to your set up?
http://www.innovatemotorsports.com/products/lc1.php

Look at the voltages that they expect to see.

If it was in my shop right now I would want to know what the original set up is doing, is the original still in the vehicle?

Mick wrote on Jan 26^th, 2012 at 12:19pm:

GRUSS wrote on Jan 26th, 2012 at 11:23am: I have a wideband innovative LC-1 sensor and controller on the exhaust as well,its a standalone unit not connected to the ecu So you modified the vehicle? Is this the site that would apply to your set up? http://www.innovatemotorsports.com/products/lc1.php Look at the voltages that they expect to see. If it was in my shop right now I would want to know what the original set up is doing, is the original still in the vehicle?

Mick
Yes my car is mildly tuned but the waveform is from the original O2 sensor that is located just after the turbo. I installed the LC-1 to monitor the air fuel ratios as I increased the boost pressure so wanted to ensure I wasn't running lean, I actually found that on a wide open throttle I was getting a 10:1 AFR which is very rich. I then fitted an special safc which is a standalone fuel computer, it basically fools the Ecu into thinking how much air it's recieving. This is done on the signal wire on the map sensor. But it only does this under hard acceleration, so normal driving and idling is still factory spec.
On a run I get a really good mpg but just driving to work daily it's not brilliant hence why I wanted to scope the O2. Hope this makes sense as I'm typing on my iPhone.

GRUSS wrote on Jan 26^th, 2012 at 3:20pm:

This is done on the signal wire on the map sensor. But it only does this under hard acceleration, so normal driving and idling is still factory spec.

Is the LC-1 sensor installed upstream of the original o2 sensor?

Are there any exhaust leaks downstream of the cylinder head?

The LC-1 is fitted after the standard O2 sensor (approx 1.5 feet if you measure the exhaust front pipe and bend etc)
There are no leaks on the exhaust system as I have it on the ramp at work every couple of weeks to give it a check over.

GRUSS wrote on Jan 27^th, 2012 at 10:57am:

The LC-1 is fitted after the standard O2 sensor (approx 1.5 feet if you measure the exhaust front pipe and bend etc) There are no leaks on the exhaust system as I have it on the ramp at work every couple of weeks to give it a check over.

I don’t know the strategy of this add-on that you have but I think it’s time to show both 02 sensors at idle and then at cruise.

You say the add-on only functions at cruise so let’s see if it goes into action at higher rpm and see what the original o2 does at this point.

If you can’t get that original 02 to swing from 200mV to 800mV then it’s either dead or that add-on is messing with the ECU.

Mick
The LC-1 is jus a standalone wideband sensor with it's own controller, it's not connected to the ECU in any way. It does have output wires that could connect to a standalone ECU or data logger. The apexi SAFC is connected to the signal wire on the map and simply intercepts the signal voltage going back to the ECU, a crude method but works well. This however only works under hard acceleration or full throttles it's connected to the tps.
I know when cruising that the LC-1 is displaying a 14.7:1 airfuel ratio which is spot on, so I'm assuming that the factory sensor is doing something at cruise. Does that make sense? Sorry if I've confused matters.
Will retest the factory single wire O2 today and apply some revs and see if it's swings.

GRUSS wrote on Jan 27^th, 2012 at 11:52pm:

I know when cruising that the LC-1 is displaying a 14.7:1 airfuel ratio which is spot on, so I'm assuming that the factory sensor is doing something at cruise. Does that make sense

It will be interesting to see them both perform together.

I thought at first the LC-1 had influence but it is just an idiot light as such.

I look forward to your results.

Mick
Not sure how to take your last comment...
I'd hardly refer to a wideband sensor retro fitted onto a car with a standard narrow band sensor an idiot light?
I put it on so i could tune the air fuel ratio of the engine, it came from america as there quite big over there.

I was getting a very rich mixture of 10:1 @ WOT after a bit of trimming i brought this down to 11.5:1 which transforms the feel of the engine.

I will have another go at testing the original sensor as the wideband controller is tucked away safely under the center console...

GRUSS wrote on Jan 28^th, 2012 at 7:49am:

I'd hardly refer to a wideband sensor retro fitted onto a car with a standard narrow band sensor an idiot light? I put it on so i could tune the air fuel ratio of the engine, it came from america as there quite big over there.

You said this add-on does not affect the ECU so then it’s just a confirming to you what your ECU is telling you in the data it sends out to your scan tool or scope when you connect to the original sensors.

The dash board is full of idiot lights battery, oil, headlamps, and now you have and air fuel ratio one. That all I was saying no offence to you at all.


GRUSS wrote on Jan 28^th, 2012 at 7:49am:

I will have another go at testing the original sensor as the wideband controller is tucked away safely under the center console...

When you do this hook up to the other one you installed as well use a  second channel.

Mick my apologies if I came across a little strong in my previous reply  :)

I've got a new O2 sensor that I will try and fit next week and retest.

Gruss

Here is a good single wire 02 off idle

Ray

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Rayray

Thanks for the capture, I'm getting nothing like that. I did retest it last weekend and took some captures whilst revving the engine. It did look as though it was trying to swing but the highest I think it got to was around 400mv. I would post the capture but it's sat on my laptop at work.

I did also seem to get quite a lot of noise as the connection is sat next to the cop no3. Hopefully the new sensor will sort it.

The only other thing I'm puzzled about is that the standalone wideband reads ok at idle (14.7:1) and is ok on light cruise. I let the car run out of petrol last weekend and checked the wideband, it gradually went lean until it cut out so it's working...

The engine when cold on first start up will be in open loop and I persume it
Uses the map or the engine ECU? Then once warm should go into closed loop and take its readings from the O2. I think that's how it works?  :-?

GRUSS wrote on Feb 12^th, 2012 at 9:35am:

Hopefully the new sensor will sort it.

Why new ? have you any proof the old is U/S ?

Ok got my new universal o2 sensor this week and stayed behind at work to fit it, after using some extreme heat and a tap to clean the threads up the new sensor is in!
I only had 5 mins before the workshop got locked up but i managed to take a couple of captures of the new sensor....
I've been playing around with the resolution and the low pass filter settings to try and clean up the waveform as i was still getting quite a bit of interference from the engine. I'm quite happy with my first real scope diaganosis though  

The difference in drivability stands out straight away, pulls loads stronger when accelerating and generally feels more responsive!

Couple of questions... how do i save the file as a jpeg? cant seem to see the jpeg option in the drop down box?

Obviously i've played around with the settings but are these the best?

many thanks

PS
I did attach a waveform of the original o2 at idle but hes the original sensor whilst revving the engine at approx 2000rpm..

Also maybe i was a little selfish on over congratulating my self, thanks for all the valid helpful replys. I'm slowly learning!  :)

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GRUSS wrote on Feb 14^th, 2012 at 11:11am:

Couple of questions... how do i save the file as a jpeg? cant seem to see the jpeg option in the drop down box?

You can't at the moment.

GRUSS wrote on Feb 14^th, 2012 at 11:11am:

Obviously i've played around with the settings but are these the best?

You tell us, does it look better in the modded file or when its all hairy without filter ?

GRUSS wrote on Feb 14^th, 2012 at 11:11am:

I'm quite happy with my first real scope diaganosis though

What did you diagnose ? i saw nothing in the way of proof that the sensor was U/S, did you force it rich & lean & post the results ?

Quote:

GRUSS wrote on Today at 2:11pm: Couple of questions... how do i save the file as a jpeg? cant seem to see the jpeg option in the drop down box?

If you copy as image and paste it to a edit program as simple as paint you can save it as jpeg from there.

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GRUSS wrote on Feb 14^th, 2012 at 11:11am:

Ok got my new universal o2 sensor this week

This maybe a false pass for you at the moment, I say this because the original and universal may not be designed to work the same.

But let’s say they are the same for now, did the LC-1 give you different air fuel ratio readings than before?

How does the new o2 look on the scope at 2000 RPM?

Mick
Getting any genuine parts for my car is almost impossible here in the uk, I didn't even attempt to get a price from a daihatsu sensor. I suspect it would be very expensive going on previous parts.

The engine did run ok before apart from poor mpg so I'm hoping this will improve things.

I've not had chance to do any proper testing with the scope as I ran out of time but once I got it warm and revved the engine the sensor switched nicely. The capture above is around 2500 rpm.

The LC-1 seems to react faster but other than that is like before. That's what i can't understand. If the sensor was dead and it looked like it was from the previous captures then why was the LC-1 reading ok..

Either way it's working compared to before. Ill see if mpg improves o er the next week.

I also need to have a look at the LC-1 wideband output when I get time  :)

hey gruss its good that you are testing and good that some members are giving you some decent sujestions and help.

did you keep the old sensor?

whats the ohms/resistance reading compared to the new one? i know you want to use the scope but at least you can prove it to any doubting party's. it will be a dif reading but may prove your point :)

you can bench test it off the car with muilti meter and propane torch using a muilti meter or scope maybe?  its old school but so is your sensor :)

connect vice grips to the sensor body threads sit on bench connect the ground lead from meter on grips and conect the signal wire to positive , set on 2 volt scale not auto or connect the scope for timing which could be interesting. get propane torch (b&q 8 quid) light it up and heat the sensor tip moving flame constantly  it should reach .9v or 900mv within 60 seconds, then pull away it should go back to near zero or origional voltage within 3 seconds , if neither of these are met then its fcuk'd or if its reading a high voltage before heating  :)

someone may shoot me down ;) and i know you wana use the scope to test but at least you can bench test prefrebly with scope as you will be able to see the exact times. and post the proof  ;)

the propane can be used to feed into the engine also to do the same test on the car to drive it to 900mv rich then pull an air pipe for the lean test whist car running which i think someone commented on but never actually told you how  :)

kennyp wrote on Feb 14^th, 2012 at 3:37pm:

which i think someone commented on but never actually told you how

Why would i have to tell a dealer tech how to do this ?


kennyp wrote on Feb 14^th, 2012 at 3:37pm:

you can bench test it off the car with muilti meter and propane torch using a muilti meter or scope maybe?  its old school but so is your sensor

I know which test you talk about, but isn't the best test bench on the car its self ?


kennyp wrote on Feb 14^th, 2012 at 3:37pm:

whats the ohms/resistance reading compared to the new one?

Can this be measured on a single wire O2 ? I can't say i've tried myself as i only measure the resistance of a heater circuit.

Quote:

Why would i have to tell a dealer tech how to do this ?

not every one is a genius like you, and has had the chance in between being told too do servicing clutches ball joints or whatever being pushed from pillar to post. where did you learn your genius rob? was it taught to you, or were just born with it? it seems to me  you dont want to help anyone or share your wisdome but more pick holes in every ones way of doing things


Quote:

I know which test you talk about, but isn't the best test bench on the car its self ?

this may be but if its off already he should test it, which will tell us 100% weather it is knackered without worying about other variables  like exhaust leaks intake leaks bad map etc plus you can tell just by looking at it if its contaminated or if its been running rich/lean the eyes and sense of smell are wonderfull tools and whats wrong with the test why isnt it the best ?

[edit]Can this be measured on a single wire O2 ? I can't say i've tried myself as i only measure the resistance of a heater circuit. [/edit]

you tell us, why should you ask such a question rob dont you allready  know the answer ;D

http://www.autonerdz.com/cgi/yabb2/YaBB.pl?num=1094423353 heres one for you rob  :)

ps. i'm not biting this time rob, but for some reason you seem to get envolved in discusion ask to many questions and dont give enough constructive answers. only my view and as ive said to you before, possibly in a more agresive manor tbh, hence the reason we butted heads in the past. this is water under the bridge and i'm not holding a grudge  :)

Very well put Kenny...

Kenny,
You've raised some interesting points here. As someone very new to scopes I appreciate all the advice and help I can get, I understand it's a learning curve.
I have noticed that rob likes to picks holes in practically everything I say, he never gives straight simple answers and comes across as not been very friendly ( or maybe its just me?) I'm pretty sure at some point not so long ago he was also new to this and also liked to ask questions...
At the end of the day we are all here to learn. The new guys and the pro's. In today's motor industry we need to stick together and exchange experiences, as far as I'm concerned... That's how we learn the most.
This is in no way a dig at you rob, I have been biting my tongue on here and on the uk pico forum but please snap out out it, I'm sure one day you will want some advice or more importantly someones opinion.
I have come here to learn from my new purchase and have really enjoyed using it for the past few weeks, I know I have a lot to learn but hopefully this forum and the uk pico forum can help me out greatly.
Let's just get on and move on from this.  :)

Russ

I must say that I have deleted my previous post. I become angry when co-workers belittle me or inocent others if their remarks are unfriendly. I find that Kenny is brave enough to speak up.
   I think Robski ought be barred from this forum.

fisher wrote on Feb 15^th, 2012 at 7:31pm:

I think Robski ought be barred from this forum.

We try to avoid that and let the natural consequences take care of things.  It's worked very well for over eight years with one notable exception.

As stated in the link posted by Kenny...


Quote:

one of the natural consequences of belittling others is that you will likely not have anyone to talk to here because everyone will simply ignore you.

It's amazing how effective that is but everyone has to be on the same page for it to work.   ;)

I'm on that page  ;) ... now

fisher wrote on Feb 15^th, 2012 at 7:31pm:

I think Robski ought be barred from this forum.

Why would that be Fisher, because i have challenged someones methods ?

GRUSS wrote on Feb 15^th, 2012 at 3:22pm:

This is in no way a dig at you rob

No dig taken Gruss, don't forget i'm on the public section & certain "Pico group" members don't like too much info in this section & ask for such to be posted in the group section, so it works both ways there !

I could not understand why you had not forced the O2 sensor rich & lean to watch its reaction whilst still on the car,in my eyes you had no real proof it was defective & went & bought another.


kennyp wrote on Feb 15^th, 2012 at 1:36pm:

ps. i'm not biting this time rob, but for some reason you seem to get envolved in discusion ask to many questions and dont give enough constructive answers. only my view and as ive said to you before

Same applies above Kenny  ;)

PS if i help anybody on a forum that isn't just for trade it is done by PM & for which i have my reasons.

Rob,
To be honest I've never used that method before, it's something I've never done. The original capture shows that it's not doing a great deal. I attempted to make it do something by getting the engine hot and revving, it did then start to move to around 400mv but wouldn't swing. To me that was fairly conclusive evidence. The sensor is original I suspect and has been on since 1998, the general engine running has got generally worse and so has the mpg. It cost me £12 delivered for the sensor so wasnt bad.
You can see the new one is working and I'm happy  :)

Put your self in my shoes and look back at the replies you gave me, you hardly ever answered my questions.
All I'm after is guidance and opinions, using a scope is a new thing to me altogether, and I'm pretty sure you were in a similar situation...

Your obviously pretty good at using a scope and getting the most from it and one day I hope to be like that, but it's not going to happen overnight I'm afraid.

Can we start fresh and put all this behind us?  :)

Hi GRUSS, First, I can tell you that any original O2 sensor from a '90 move is certain to be dead. They do exactly what you showed in the first couple of captures, where it stays flat-lined, very near 0v no matter what you do, or they have very little response on a snap throttle test. These old Daihatsus, and the other kei's for that matter, don't enter closed loop and will stay pretty flat around .4v until you get it off idle. All of your captures are exactly what I see before and after, and I've done plenty of them. With the kei's, it dramatically improves gas mileage and performance.

Cost new for one of these old one-wire OEM sensors is around US$300-400.

Cheers,
Matt

Matt H wrote on Feb 23^rd, 2012 at 4:01pm:

Hi GRUSS, First, I can tell you that any original O2 sensor from a '90 move is certain to be dead. They do exactly what you showed in the first couple of captures, where it stays flat-lined, very near 0v no matter what you do, or they have very little response on a snap throttle test. These old Daihatsus, and the other kei's for that matter, don't enter closed loop and will stay pretty flat around .4v until you get it off idle. All of your captures are exactly what I see before and after, and I've done plenty of them. With the kei's, it dramatically improves gas mileage and performance. Cost new for one of these old one-wire OEM sensors is around US$300-400. Cheers, Matt

Hi Matt
Thanks for the reply, your probably right with the proper diahatsu price, I daren't even check going on previous purchases. They wanted £240 for a bottom arm! I got 2 for £48 delivered off the net.
Well it's certainly improved the car all round and it lots better on fuel....once again