Voltage on p38 gems lambdas

sandyt · Sep 23, 2013

Gents getting .15 to .89 on bank 2 and .02 to .98 on bank A great but everywhere I read that gems should be 5volts ? did any of the gems 1998 have the cheaper o2 sensors or have I got the wrong downpipes and wrong lambda cant see it but you never know

MrGorsky · Sep 23, 2013

Standard range is 5v lean and 0v rich.

Mine usually goes from 0.5v to 4.6v or thereabouts. Yours does not sound right to me.

Even if the wrong lambda sensors were fitted, the ECU would still always be thinking the mixture is too rich (no matter what it did to correct it), and would throw an error light eventually...

sandyt · Sep 23, 2013

The problem is that the sensors were changed in 1998 scrap that yours is the same age.
If it was one then fine but they are both toggling up and down as they should I took some off another p38 1996/7 but they have a different connector. Also noticed that the coolant temp registers at 75c so suspect coolant sensor to ECU is wrong but that would ask for rich not leanwhich 1v would be on one type of sensor but rich on the other confused dot com

sandyt · Sep 23, 2013

I am wondering if the down pipes are wrong and have the thread for the thor engine lambdas as sure I have read the sensors have a different thread

sandyt · Sep 23, 2013

No scrap that too as the sensors from the 96/97 fitted but the connectors were different

jacckk · Sep 23, 2013

Are you checking using diagnostics?

My diagnostics shows it in the range of 0-1 but probing the pins directly at the ECU does show the correct 0-5V response.

MrGorsky · Sep 23, 2013

What diagnostics are you using?

My Nanocom shows 5 - 1 volt swing on my GEMS engine.

jacckk · Sep 23, 2013

I'm using Lynx.

MrGorsky · Sep 23, 2013

Maybe it's a Lynx thing then?

I'd offer to come and compare it Sandy, but the Nanocom I use is my brothers and he's got it up at his house at the moment.

As long as it's swinging from rich to lean it's working properly!

Saint.V8 · Sep 23, 2013

Maybe the Lynx readings are decimal readings 0 - 1 : 0=0v and 1=5v

Therefore:

0.15=0.75v
0.89=4.45v
0.02=0.1v
0.98=4.9v

Just maybe!

jacckk · Sep 23, 2013

Saint.V8 said:
Maybe the Lynx readings are decimal readings 0 - 1 : 0=0v and 1=5v

Therefore:

0.15=0.75v
0.89=4.45v
0.02=0.1v
0.98=4.9v

Just maybe!

Quite possibly!

As far as I can remember it didn't show a unit at the end, so you're probably right.

sandyt · Sep 24, 2013

Sorry everyone was working doing a dish migration at the Beeb right so yes using lynx diagnostics which happy for others to use and I think that the conclusions are right that it is a scaled value between 0 and 1

Voltage on p38 gems lambdas

sandyt

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