p38 4.0 lpg

[shealyp38]

sensors were bought against my chassis number from island 4x4
http://www.island-4x4.co.uk/oxygen-lamb ... -2196.html

[Gilbertd]

Typical Simon, read half the post then give information that isn't relevant.

They are definitely the correct sensors for your car so that isn't the problem. Take the MAF off and give it a good squirt of carb cleaner to make sure it's clean and working as it should. At least the trims are correct when running even if not when at idle so it's an improvement. Both codes relate to sensor heater circuit but you've already confirmed that you have 12V at the sensors if I remember correctly. We've just got to work out why there appears to be no output from the sensors. It's running rich, the trims confirm that, so I would expect to see the sensors giving a high reading of 0.9-1.0v, not zero. Are you sure there is no reading when it is being driven and the trims go down? For the ECU to bring the trims down, it must be seeing something to tell it to do that.

[shealyp38]

i was using scantool to grab the live data while it was driven but not sure how accurate it is
later ill get under the car and get someone to rev it while i get the voltmeter out
as for the maf i got a new one ordered as i did clean it the other day

[rossko]

I think we ought to clarify exactly what engine management is present here. Bosch with bananas on top of engine, or GEMS with box on top?

GEMS misreports the airflow to most OBD scanners, and reads a factor of ten low. So 0.55g/s at idle is in the sensible range - but not necesserily absolutely correct. These engines should idle in the 5.5 to 6.5 g/s range when hot, it varies by temperature etc. so its hard to spot something just a little out.

However if you have the Thor/Bosch then airflow should read good, presuming your OBD software is working right - 0.55g/s is wrong. MAF is a common failure on these systems, its non-obvious and a bugger to diagnose because it doesn't break, just reads a bit low.

All these comments about MAF assume you've already made careful checks for vacuum leaks e.g. pipes or plenum gasket.

[shealyp38]

ive just been speaking to someone about this problem
and they said i may have a broken wire between the sensor and the ecm seen as ive still got the two fault codes

[shealyp38]

just been in my garage to test the old sensors
heating them up with a blow torch and hooking up my voltmeter im seeing a reading of 0.9v and below
remove the heat and it drops to zero
would i be right in saying these sensors are ok?

[rossko]

They're probably good, although it isn't a comprehensive test.