Electrics: SRS and Emissions for MOT

[bimmer49]

Quote:
Originally Posted by bimmer49 View Post
Well it's the annual test time, ITV.
The SRS light has been on for ages (it usually is when someone sits in the passenger seat) but my Foxwell 630 will turn it out. WRONG! Same old Intermittent fault with SIPS bag connection. PLUS SRS unit permanent fault! Oh no! Tried several times to erase the codes but no good.
Replaced it with the old unit, only the Intermittent fault showing but it will not put it out!
Checked connections to no avail.
Taking it for test to see if it fails on anything else in the morning. It's difficult to get tests here at the moment but a retest is no problem.

OK ladies and gents: Car failed on Air bag light illumination and accelerated revs (3000rpm) high CO level (60), I also noted a fluctuating lambda figure 1.010 to 1.023.

I checked continuity from the SIPS (B post) and seat (underneath seat) airbag plugs back to the SRS plug. All OK. I tried to erase codes with the SRS module resting in the middle. I noticed the tick tick tick had gone from the red flashy light until I earthed out the STS module. I cleaned the mount bolt holes and refitted the unit. I then scanned the unit and 2 faults as per usual listed. I did a quick erase and hey presto they were gone! I did it 3 times and even sat in the passenger seat bouncing up and down, the light stayed OFF!

Now comes the tecky question about the emissions. I'm none to good on petrols

On "Live" data I see that the Oxygen sensor output voltage on Bank 1 Sender 1 is ranging from 0.260 - 1.275V where as Bank 1 Sensor 2 is a steady 1.275V. Is this the cause of my fluctuating CO and Lambda emissions?

Now I haven't cleaned the MAF. Would it be a contributory factor?

[bimmer49]

Seems MULTIPLEX (Chris) is the man for my emissions answer!

[bimmer49]

Short version here: SRS light turned out after continuity checks made back to the control module. Regrounding the module body to the car (it requires earth) and the Foxwell 630 erased the error codes and everything hunky dory!
Oxygen sensor 1 bank 1 giving fluctuating voltage readings, similare to the CO/Lambda readings on test. No one has come back with what it should be doing so Im still tending to a defective sensor.

[gatos]

Replacing the O2 sensor should be the first logical step and see if it solves the problem. They tend to fail after many many years of use. Have you tried blasting the car and doing an Italian tune up? Sometimes it may help a bit.

[bimmer49]

Hi gatos.
I read about the "response" time of a Lambda sensor over time, they get lazy and can't keep up with requirements. Whether this is deterioration or contamination I can't say.
I'll take it out, get the reference number and give it a clean up, carb or brake cleaner might do.
No I didn't give it stick but I ran the car whilst waiting to go in so engine temp should have been 90+.
Locally I am being quoted 148€ for a Lambda sensor! No thanks.

[gatos]

Find out what the part number is and let me know. I have a few spare lambda sensors, so I can check if I have the same one

[bimmer49]

Moving on:
A bit of spare time today to see what I can find.
First job, remove all 3 lambda sensors. First one:31104892, was a sooted up, more than i would have expected. The other 2 less so.
Gave them the carb cleaner experience and refitted them.
Maff got a wash from the magic spray too but it was clean.
Plugs out. No.1 was unexpectedly black but not as they would get in a leaded engine. Been a long time since I saw a plug like it. Not clogged, just sooty. Gap 0.65mm which is about what I set it for with the LPG. Plugs 234 were all nice n clean, plug gaps 0.65.
Now if No.1 injector is weeping a bit, this could be the source of my ailments, the no.1 lambda struggling to alter the fuel mixture enough to cut down the emissions, hence the soot on the sensor itself. (Funnily enough, the tailpipe was a bit on the black side recently).
Next bout will be some injector cleaner and an "Italian Tune UP" thrashing (thats if we havent gone into lockdown by Monday).
NOW: I could take the car for test running on LPG but one tester insisted on petrol, this last guy never even looked. A lot of moisture forming in the tailpipe too at 3 pm and 25 degrees ambient (there was a lot to at test but that was 08.30 and 10 deg!)
Surely the MIL should illuminate if the emissions were not up to scratch?
Previously there was an annoying erratic misfire on tickover, mainly on LPG. Now not a hint of one on petrol (which must help). I cant test LPG running cos I aint got nun!

[bimmer49]

I've gained like everyone else has due to suspension of annual testing.
So, as No.1 plug was sooty I took out plug 1 and 2, cleaned them, swapped them over, removed injectors 1 and 2, they looked good and swapped them round.
I'll check them in a few weeks.