37 replies to this topic

[96minimig]

Hi there, I am at my wits end with my spi mini but would like it spi(not carb' d before the comments roll in)

Basically my single point injection always struggles through its emissions on the mot and it's had a recent new cat fitted for the mot but still struggled. I have recently obtained a acr2 or Sykes Pickavant tool to which when I tested my old lambda volts they were only switching every second not twice a second or more so I guessed it being an old lambda I went about replacing it.

Since replacing it with a Bosch lambda sensor it only shows 0.8 volts which according to the booklet is limp mode. When cold and when warm nothing changes. The car runs fine but I am guessing that will fail the MOT as its slightly rich. I even bought a aftermarket lambda for a rover mini and fitted it to eliminate a faulty sensor and it's still the same.. I need help where to go next as I am pretty stumped to be fair.

I have checked and fixed the following:

Lambda connections and plugs etc.
Lambda component test to heater relay via Sykes tool
Vac hoses
Exhaust pipe itself
Fault code found with air inlet temp sensor in air box wire broken
Fault code cleared to air inlet temp sensor wire fixed and now working.
No fault codes found
Checked lambda volts again after this and still at 0.8 volts

[FlyingScot]

Using Rover pod 1?
Check the actual heater voltage with a multimeter on the lambda sensor plug when you trigger it. The component test only activates the relay (tyco yellow one) it does put confirm the voltage is present on the output side or reaches the lambda sensor itself.

FS

[96minimig]

Yes tested that too:
Had 12v power to heater wire
And then smaller figures on the other two and then obviously 0 on the earth connection wire

Edit- using rover pod1

Edited by 96minimig, 06 January 2016 - 06:32 PM.

[minidaves]

what rocker cover have u got?

[96minimig]

Erm a standard black one why lol

[Fast Ivan]

What are the other sensors doing? Are they working as they should, I don't mean are they showing faults, I mean for example does the coolant sensor gradually increase as the engine heats up, likewise the iat.

[FlyingScot]

Is the lambda value not changing at all? Do you hear the engine hunting a bit as the timing/ feeling is adjusted as she idles?

All mechanical aspects spot on ? (Tappets, plug gaps etc)

FS

[96minimig]

Hi Fast Ivan,

Yes other sensors working fine

Coolant temp is 89 degrees when warm temp gauge is also just below half
Air temp sensor is around 17
Map sensor is around 34
Engine speed is registered so crank sensor is working and idle speed when warm is around 850rpm
Battery volts charging 13.8 volts

[96minimig]

Lambda just says 0.8 volts from cold to warm but I mentioned above FS the engine is running ok no misfires and does the usual warming up process of slightly higher idle then as the coolant temp warms up the idle speed goes from around 1100rpm to usual 850rpm. No hunting in the engine at all. Plugs are or were before changing sensor bronze colour and gaps fine. Tappets were done last year but only done 4000 miles since

Edited by 96minimig, 06 January 2016 - 08:44 PM.

[96minimig]

I may have to check the wiring tomorrow night. To double check to the heater is working.
Would it throw it to limp mode even if the heater doesn't work when warm.
I recently tested a mates car which was working and it's started at 1.1 volts then as it warms up its switching gradually getting quicker from 1,1volts to 0.1 which is how it should. Mine is stuck on 0.8 volts which according to the Sykes Pickavant book is the sensor is limp mode which tells the ecu to run slightly richer like every other limp mode systems on ecu softwares

[FlyingScot]

Very odd, motor seems to be running okay. Wiring from lambda is okay back to ECU plug?
Might be worth putting a multimeter on the lambda plug when warmed up and checking the voltage directly if you have a digital multimeter (heater effect would be nullified by the hot exhaust gases). An oscilloscope would be better but I'm guessing a multimeter might be possible?

FS

[FlyingScot]

I may have to check the wiring tomorrow night. To double check to the heater is working.
Would it throw it to limp mode even if the heater doesn't work when warm.
I recently tested a mates car which was working and it's started at 1.1 volts then as it warms up its switching gradually getting quicker from 1,1volts to 0.1 which is how it should. Mine is stuck on 0.8 volts which according to the Sykes Pickavant book is the sensor is limp mode which tells the ecu to run slightly richer like every other limp mode systems on ecu softwares

Heater coil effect is needed when exhaust gases cool, so if motor is hot you can discount. Sounds like a wiring/MEMS fault.

Could also be a bum lambda - even new parts fail.... Did you keep the old one ? I know you tried a pattern part but they aren't worth toffee

FS

Edited by FlyingScot, 06 January 2016 - 08:55 PM.
Another idea in action...

[Fast Ivan]

So it's running ok with no noticeable problems, the sensors all work as they should other than the lambda. Your concern is that it may be running rich, is it actually running rich or are you assuming it is because of the lambda reading? Any smoke out the back? What do the plugs look like after a run?

[96minimig]

Yes FS I know the universal lambda maybe crap have heard lots of people say they are false economy buying them but just bought it to eliminate the faulty Bosch one. Obviously will fit and try the Bosch one once I know it can work. To be honest the Old sensor I took out which worked but was lazy didn't look like an original part it had Japan stamped on it with a number and looks thinner than the Bosch sensor and universal I have bought. The universal one looks exactly the same shape and end as the Bosch one, it just didn't have Bosch stamped into it or the OEM plug. I didn't keep the original sensor to use again as it broke getting it off as I am sure your aware they are pretty tight getting the off the car.

Yep that's right Fast Ivan I would like to go through the emissions a bit easier as it scrapes through but usually fails quite often. No smoke out the back haven't checked the plugs after running it. Have barely gone up the road and back as well but warmed the car up thoroughly before doing the above work. Will check that too tomorrow.

Thanks for replying so quick by the way chaps :)

Edited by 96minimig, 06 January 2016 - 09:45 PM.

[96minimig]

Hello again had another go tonight with no joy. Tested and check connections again. Getting 12volts reading from heater wires and low voltage from signal wires at the lambda plug when running.

Still stuck in 0.8v which is so annoying.
Check the spark plugs and they are still nice bronze colour not black.
Didn't even take it down the road this time just warmed it up in garage but still showing no life from the lambda

So disheartening. I have a friend who has a mot emmissions probe so might fit my CAT and get over to him to see if it will put out passable emmission readings but don't know when. I haven't got a lot of faith though as I am certain it will be slightly rich which is enough to fail it