P38A Help with using Blackbox GEMS Module.

Hi
I've been struggling with my P38 1997 4.0se emissions.
I have the Blackbox Gems Module, plugged it in tonight to see what readings I am getting from the Lambda sensors.
1. What valve would a good sensor read?
2. Would the reading increase as I dip the accelerator?
What other things should I be looking at which would help solve my high CO values on my failed emissions.

Colin from Hull said:

Hi
I've been struggling with my P38 1997 4.0se emissions.
I have the Blackbox Gems Module, plugged it in tonight to see what readings I am getting from the Lambda sensors.
1. What valve would a good sensor read?
2. Would the reading increase as I dip the accelerator?
What other things should I be looking at which would help solve my high CO values on my failed emissions.

Click to expand...

Might help if you posted the readings you are getting.

Are the lambdas switching? Any codes stored? Air leaks are a classic mixture messer.that could be anywhere between the maf and the lambdas.

If all sensors are throwing faults them replace the MAF sensor. These friggin things are always failing & keeping emissions high.

Other than that, try & get the live data of each sensor & see if it's switching during revs.

Make sure the engine is warmed up properly also.
Air flow meter should rise and fall with the accelerator pedal.
The front lambda should also follow.
The rear lambda is a little more subdued but should also react.
Check also the air intake temp and engine coolant sensor they all have an effect on the mixture.
As suggested vacuum air leaks can and will upset reading after the maf, considered unmetered air!! Good luck.

As has been said already, check what live data or any other measurements you can and post here.
Not sure what the black box shows for the Lambda readings, lambda or voltage.I believe closed loop is in the range of .95-1.15 lambda,(lambda 1 is perfect). But as you are high on CO your are unlikely to show this reading, also what were the other gas readings? CAT should scrub out a lot ( do you have them?)
The car being up to correct operating temps is critical.
It could be something as simple as old/fouled plugs.

Get as much info as possible and post it up. There could be so many things or just 1 simple answer. But without (lots of) info it’s really difficult for it to be pinned down.

J

@Colin from Hull , how did you get on buddy?