MOT emissions test

[stigmundfreud]

Now that the car is running mafless semi-openloop with the 02s disabled what effect will this have on the MOT lambda test?

Edited by stigmundfreud on Wednesday 11th July 16:03

[ringram]

semi open loop is closed loop with o2 when you tell it to run at an EQ/Lambda ratio of 1 outside of that commanded ratio its open loop.
The MOT test expects you to be close to stoich for one of the tests.

If you have your ve very accurate and tuned for temperature etc you can pass in open loop. But to save time/hassle make sure you are at closed loop at idle and at the 3000rpm test points.

[stigmundfreud]

guess whos going back to check what loop he is running in

I'll just whack commanded to 1.176 at idle and 3000

[ringram]

It needs to be stoich. You get like 0.97-1.03 range allowable. Best to keep to closed loop for the test for sure. Then open afterwards if you want to for more economy.

[stigmundfreud]

gotchya, I'll get working on that map - I've got a year to nail it down

[ringram]

Also just a clarification, semi open loop is only available in the custom OS's and is basically closed loop fueling with no long term fuel trims. So acts as though you have done a PCM reset each key on and doesn't lumber you with additional fueling you dont need from the fuel trims.

So its a better closed loop than the factory one. (It doesnt add extra fuel at WOT like the factory one does, which can lose power)

[Island boy HSV]

Do you guys not have each others phone numbers??

[VXR_Daz]

ringram said:

semi open loop is closed loop with o2 when you tell it to run at an EQ/Lambda ratio of 1 outside of that commanded ratio its open loop.

I can honestly say I understand 0% of that! Is it in some alien language or something?

[white and proud]

Sooooo currently ltft are turned off so relying on b3647 (currently all dialed in at eq ratio of 1.0 to 80kPa then 1.176 from 85kPa onwards)

b4108 stft is enabled

if my understanding is correct, as ltft are disabled the car is using b3647 exclusively for fueling. As I have set table to be stoich at all but a pressure of 85kPa or above then it will use stft until I open the throttle where it will go into full open loop?

so below pressure of 85kPa it is in semi-closed loop using the stft/o2's to tidy things up then at 85kPa or above is open loop - is this the correct understanding?

If I then come to MOT time, just enable LTFT and set the ltft enablers to get it into closed loop then revert back afterwards?

[white and proud]

VXR_Daz said:

ringram said:

semi open loop is closed loop with o2 when you tell it to run at an EQ/Lambda ratio of 1 outside of that commanded ratio its open loop.

I can honestly say I understand 0% of that! Is it in some alien language or something?

I can honestly say last week I understood 0% of it, this week I understand 1% of it.

Island boy, yes we do but I'm too tight to call

[ringram]

Well I wasn't sure it was aimed solely at me, but if it is I'm happy to take it to PM

But yeah thats basically it. Though semi open loop is fine as long as the o2's are triming you dont need LTFT's.

Plus check your PE enablers as they determine when you are in PE mode as well as B3647.

Flick me a PM to save forum chaos if you like.

[stigmundfreud]

will do tomorrow fella

just figured that these threads may come in handy for others in the future as tehy go through the learning curve
sure I could go to the efi forum but I figured this a better place to blog my thoughts, questions, findings and your answers/corrections

[VXClubby]

Mate I've just seen your crash video, you're lucky to be alive to trim your AFR by the looks of it! Amazing vid.