Secondary air pump removal

[s4mmie]

After reading pages and pages of threads over on vwvortex about deleting the secondary air pump I've yet to find any concrete answers about the effects on the fueling of removing it. I'd love to remove all the emissions gear but it seems that it takes a few days for the ecu to adapt and turn off the CEL. Putting resistors in the SAP wiring fools it into thinking the SAPs still there but the ecu will still throw an 'improper flow' code. Apparently the only way to remove this is to have a tuner remove it via software. As I understand it, the SAPs function is to recirculate air on startup to heat the cat converter up to operating temp. Would removing this system (or hqving a CEL) affect the fuel maps? Has anyone had any experience deleting emissions systems on their car? And WTF is the EVAP system for? (blue balls)

[noone]

I've had the secondary air system and reservoir out. I got over the orange light on the dash and put it back. Not that big of a job aside from installing the blanking plate. IMO, there is no real gain, more preventative.

[s4mmie]

Did you notice any difference with the fuelling? richer/leaner, etc. I may be dreaming but I remember reading somewhere on the interwebs that the 'incorrect flow' code could affect fuelling? If it's just a matter of clearing codes and disabling the CEL then I'll prob go ahead with a full delete. I hate 1-billion hoses for emissions in the engine bay ...and this looks sexy:


...full emissions delete with just the necessary hoses (catch can, dv, fpr, etc).

---------- Post added at 02:35 PM ---------- Previous post was at 09:59 AM ----------

Actually I remembered what it was.. I read a heap of posts saying if your car hadn't been CEL free for 'x' amount of kilometers than you wouldn't pass emissions testing, which is what makes me ask about the maps.

[noone]

the SAI system is to heat up the CAT faster, or so the theory goes. The issue is that a small leak or valve not closing properly can cause issues or rob peak power. The code is that the flow is wrong, don't seem to be able to get around it on the ME7.5 without tuning.

As for richer / leaner, any fueling issues can be resolved / worked around by the ECU. The computer knows all...

[Jmac]

If you have seen any car first up in the morning that has a disconnected pipe or it has fell off the SAI ( more often the case) you will notice black smoke on start up, this is becasue the mixture is rich when cold or the engine will naturally cut out. Now with the rich mixture the SAI pumps air downstream to the cat and lessens the super rich mix and at the same time raises the cat temp so the system goes into closed loop quicker, some go into closed loop almost straight away these days especially EU5 set ups. As for the Evap flow fault not really sure why the ECU picks that fault, i can only imagine it does because the O2 sensor signals that get interpreted by the ECU then switch on the Evap purge valve ( the little thing that you all moan about that clicks from time to time in the engine bay) that lets tank fumes back into the plenum to richen the mix up, when that valve stops working or there is a leak or split pipe then that code gets picked form the ECU tables. As the SAI is emission related then that might be the code that is picked from the ECU table. Im sure this is the case because the ECU will be expecting feedback and of course the mix will be super rich, not for long though, but the ECU doesnt like it.The software calibrator would have to delete that from that particular table. As for mix of course it will be super rich on start up, has to be. No air pump to even it out. In closed loop forget about it the Fore 02 sensor and MAF takes care or your mixture
Cheers
Jmac