P38A MAF etc opinions

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Do I not want "Closed loop"?
I thought closed loop was when the lambda sensor talks to the injectors ad adjusts them accordingly.
Since she just passed her MOT woulf that mean that all is ok?
 
oakey said:
Do I not want "Closed loop"?
I thought closed loop was when the lambda sensor talks to the injectors ad adjusts them accordingly.
Since she just passed her MOT woulf that mean that all is ok?
Click to expand...

Yes It'll go into a default open loop mixture when/if it detects problems with a lambda sensor which will be a richer default mixture than it should be. No idea how much richer though although I would expect something in the region of 10-20% richer..
 
If she passed the emissions and they were in an acceptable margin then yes she's ok..

However these cars will throw a hissy as and when they feel the need ;)
 
You could have a dodgy lambda sensor so one bank is running the default fuelling strategy. Use the Nano to look at the live readings while the engine is running. You are looking for a lambda sensor that switches between 0 and 5V. If the first box shows CL, then it is fine but you may find one bank is reading Open Loop or CL Fault. You'll get no CEL and the car will appear to be running fine. You may also have a fault code for Lambda heater which means one sensor will stop giving an output at idle so it will go open loop. IMHO the GEMS does benefit from a squirt of MAF cleaner but you'll need to reset the adaptive values afterwards and let it re-learn the trims.
 
So are you now saying you have 2 full runs of exhaust pipe and they don’t join? Or it joins normally at front and then splits to 2 tail pipes? Cats? (Yes)How many Lambda sensor?(4)

I was always under impression “adaptive settings” should not be changed unless major engine/gearbox work had been carried out?

If you have the ability get live data save it. Drive for a week and check again see if anything has changed.

If it’s running fine I wouldn’t rush in and change stuff just yet gather info first.

J
 
2 pre and 2 post cat 02 sensors..

Adaptive settings on the 38a are configured over a period.

Pulling the battery or replacing a component like for instance the Maf or 02 sensors will put them up the creak.

It's good practice to reset and allow a relearn every so often anyway..

do a reset, then drive it. It will need a variation of different driving conditions, slow acceleration, hard acceleration, constant speed cruising,etc a few kickdowns as i said for it to set the values as they should be
 
Henry_b said:
2 pre and 2 post cat 02 sensors..

Adaptive settings on the 38a are configured over a period.

Pulling the battery or replacing a component like for instance the Maf or 02 sensors will put them up the creak.

It's good practice to reset and allow a relearn every so often anyway..

do a reset, then drive it. It will need a variation of different driving conditions, slow acceleration, hard acceleration, constant speed cruising,etc a few kickdowns as i said for it to set the values as they should be
Click to expand...

I suggested that on a thread a while ago. Got shouted down about it by an happy amateur. ;):D
 
Cant remember if Lambda are pre or post at, I will check today but there are definitely two. Exhaust joins to one pipe then splits again after back axle.
Would love to get live data but worried in case Nanocom disconnects while engine running and BECM throws the toys out the pram
 
It relearns adaptive values within 20 to 30 miles. I think it adjusts slowly all the time but like the salesman route problem occasionally goes a bit too far off course. LPG seems to muck it up at times.
 
should I reset with a hot engine?

I did have one injector which was a problem as the connector was loose. Think I fixed it but that is a good point I have not looked since then
 
Ok thanks folks I will reset them just before I take her for a 200mile run week after next and will report back
 
Right guys. I am by no means poo pooing anybody’s advice here.

How many adaptive settings are there in a P38?
As I said earlier I was under the impression this was only required after major engine/gearbox work.
Ok so new exhaust may now breath a little better and throw it out of whack a bit.

Why not just go through the “drive cycle listed” and let it sort it’s self out with a good drive?

It’s not broke, it’s just past an MOT, why mess?

Just my thoughts. Just cos we have these fancy gizmo boxes don’t mean to say we have to press all the buttons, when the car was designed to take care of it its self?

Now if I have upset anybody sorry but sometimes rushing in a china shop springs to mind:eek:

J
 
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