Technical Seicento MPi O2 sensor again..

[Diwiak]

thanks

 

[Ouby]

....can do live loggin and stuff which you can then transfer to your computer or laptop. It was a middle of the range one price wise (was a few years ago now but around £150 iirc)....

How much!
Maybe technology has moved on a bit since then as even cheap units seem to do that now.
Mine = Launch Creader V (OBD2, EOBD) Does everything I need (inc Live mapping) £32

 

[blu73]

it was ages ago it was purchased and it basically does everything you'll ever want it to. Sure things can be got for much less now, my point was they had cheaper ones at the time from the same manufacturer. Had a brief look at some online and they seem to vary from about £50 to £400 so i guess the new equivalent would still cost about the same tbh.

 

[Diwiak]

hi back,

cheapest bluetooth ELM327 from ebay arrived , everythings work great through MES,
http://www.ebay.com/itm/400422940789?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

as I thought there was again P0139 ("lambda 1 below cat" or something like that),

just noticed in ODO there is recorded 97570 KMs, but my dash actually shows 90 258, how could happen this??

another thing, what is "self-adaptation reset" and "phonic wheel learn reset" - any reason to run such things???

 

[Diwiak]

sorry for late answer but finally it was first lambda, bought cheap polish one, done thousands of miles, no troubles yet.
have to say, that whole car is running with no trubles thousands of miles which is strange for a F.I.A.T. (knock-knock)

 

[Red Rocket CINQ]

I've just started experiencing problems with my car and the lambda sensors. Eml light came on so checked and it showed both sensors gone, i knew one was a bit dogdy so i decided to buy 2 new ones from unto.pl since it cost me less for 2 than it would have for 1 over here. All changed car seemed pretty good on fuel and driving, went for a long drive day after and a fault came up saying fuel trim problem, so plugged my obd2 reader into it and all looked fine lambda readings looked good. Yesterday though is when the problems really started. Driving the car and suddenly it had no power and sounded like it was missing when putting my foot down so i pulled over and the car was struggling to idle and a strong smrell of unburnt fuel from the exhaust. On the way home plugged my obd2 back in and the 1st lambda wasn't reading atall. So one day next week ill put it on the ramps strip all the heatshrink off the wires and check it all, i think ill change them over and see if i get a reading from the other sensor.r

 

[fingers99]

Remember that a fault with the first lambda will (or should) always flag up the second lambda. Essentially the second lambda just checks that the first one is working.

They're identical (although wire length may differ) so can be swapped round.

 

[Diwiak]

faulty piece?? which brand??

changing only first lambda worked for me, done something around 5k miles.

 

[Red Rocket CINQ]

They were both magneti marelli, before i changed the second one i was getting no reading from it that's why i changed it, the second one was giving me a good reading until this started happening. The first one was also giving me a good reading but now its not telling me anything. Ill change the first one today and see what happens. They both have a 12 month warranty anyway so ill be sending it back if its the sensor. I've used like half a tank of fuel in 60 miles :O. There should be no need but can i clean the lambda sensor with something like carb Cleaner? Of is there a better Product?

 

[Red Rocket CINQ]

Right, i swapped the 2 lambda sensors around with same results, i also took one off a car that is working fine with the same results. Here are a few screenshots I've taken

Now sometimes the 1st sensor will say 0.0v and the 2nd sensor will say 0.2 - 0.4
Most of the time though its like it shows un the pics, i just don't understand how it can go from being excellent with 2 new sensors to this. I've checked the wiring from the plug up towards the ecu so far and it seems ok. The only thing i can think of is a problem with the ecu as its got the micro ecu.

 

[Diwiak]

these magnetti marellis will be that cheap polish fake copy- i had same brand lambda in cinq years ago, no problems.

hm both lambdas gone sounds strange to me, couldnt be something else??(too much oil in emissions causing destroying both lambdas, cat converter gone..??)

and check warranty policies, mostly they want repair certificate from authorised garage.

 

[Red Rocket CINQ]

I've taken a fully working lambda sensor out of my other fiat and that still shows the same results, not losing any oil atall.

 

[cc1]

Check both sensors resistance via the Ecu connector to confirm they are not open circuit and test wiring.

 

[Red Rocket CINQ]

They ain't open circuit when they are warm enough, usually in a few seconds as my tablet tells me when they are open and when they are closed running on 02 sensor. Im sure it must be ecu related as i had a part fitted a while back to trick the ecu into thinking there is a cat on the car, now when i started having the problems the 1st time i looked at the wiring and it was aweful, and Im thinking it must have short circuit or something. Where they extended the lambda wiring it was all exposed to water and what ever else off the roads.

 

[Red Rocket CINQ]

i plugged fiat ecu scan into my car today and there was 3 dtcs.

DTC...................................part...........................................explanation
p0170................................says nothing by here....................no signal, fatal, light on
p0135................................o2 sensor (6)..............................no signal, stored, light on
p0141................................o2 sensor (12)............................no signal, stored light on

these are the dtcs,

what would the resistance's be in the lambda sensors as they warm up?
also, is there any voltages going to the lambda sensor from the ecu that I can check?

 

[fingers99]

This looks good.

But if the wiring is still a dog's breakfast, I'd re-do it: good, soldered joints, heat shring to insulate. As I read it, the ECU is getting no signal from the lambdas.

 

[Red Rocket CINQ]

That's the way i see it, but they are both brand new and worked for a few days, i changed 1 with 1 off my other fiat which worked fine on the other car and still no signal from sensor. I done a good job, all really good connections, soldered and heat shrink aswell.

 

[Red Rocket CINQ]

Right, well an update on the problem. I started the car today for the first time in weeks, had to jump start as the battery was so flat the lights for the central looking wouldn't even work. Anyway started the car and it seems to be running fine again, but what my tablet is telling me is completly different. The 2nd lambda sensor is now giving a proper reading or was untill I pulled up out side the house, the 1st sensor wasnt giving any reading untill 5 miles ago where the reading went up to 0.9v which if im right is telling the ecu there is to much fuel going in, at this point the car was a bit slugish on take off but then drove ok when going, but the voltage never changed when accelerating or idleing so I can only think its a wiring fault as the ecu is showing my tablet its trying to put more fuel in when the voltage is on 0.0v and trying to put less fuel in when the voltage was 0.9v. When it dries up a bit im going to find the lambda wires that go into the ecu and run 2 seperate ones outside of the loom to the sensors and see how it goes.

 

[Diwiak]

I have problems with lambda again, too. ECU liught on and some connection problem with first sensor (dont remember code), did reset now its fine again, but mpg is 0.5L higher... looks like cheap polish sensor is gone

what sensor would you recommend?? are NGK, Bosch, Denso good choices?? ( but will cost me at least twice as polish one )

edit: iam brwosing through denso catalouge, and it says two sensors with different codes (I thought they are the same??) - regulating and diagnostic, regulating is first one am I right??

 

[Red Rocket CINQ]

Have you tried another lambda sensor, a known working one? This is what I tried and I have the same problem .