SAI Delete - Research so far...

[OSR]

Hi All,

***Before I get accused of not using the search this is more of a collation of thoughts and facts based on my research to date which will hopefully help others in the future***

I'm looking into performing the SAI delete shortly, however I like to check and double check before I do anything like this so I've done endless reading and research on the internet and what's confusing/surprising me is the lack of consistency around what some cars do after the delete versus others etc.

For the record my car is a 2001 1.8T AUM engine code.

The following thread on Vortex is widely accepted to be the holy grail for actually performing the DIY removal;

http://forums.vwvortex.com/showthread.php?4893472-DIY-Ultimate-SAI-N249-PCV-EVAP-Delete

And from reading numerous (mainly USA based for some reason) forum threads, two things are clear when performing this delete;

1. You must fit a resistor in place of the disconnected SAI pump. This fools the ECU into thinking the pump is still in place. Sounds simple...

2. You will get a CEL on startup due to the fresh air usually injected by the SAI system into the exhaust not being present and not being detected by the O2/lambda sensor. This will produce DTC "16795/P0411/001041 - Secondary Air Injection System: Incorrect Flow Detected" This can only be removed through software coding, i.e. the can cannot be fooled any other way.

So I was prepared to get the system removed and accept I will get a CEL, however on reading various threads on various forums there is a lot of inconsistency and that it appears that some cars throw a CEL, whilst others do not. Great.

The other thing to throw in here for info is that the US version of an MOT would appear to include a "readiness check" as part of the test, which causes all sorts of headaches for them, however our MOT is simply based on emissions and having no dash lights on.

Now I don't want to be stuck in a place where I need to reinstall the SAI system come MOT time every year to make sure the CEL is not on, so I was thinking of simply disconnecting the pump and fitting the resistor with everything else left in place to see how my car reacts and running around like this for a week or so.

In terms of coding out the CEL using software in the future, I am currently running Revo Stage 2 map - given Revo is a generic off the shelf map I'm not sure if this will allow specific parts of the code to be modified? The nearest I got to a definitive answer for this was a lot of the US forums stating that several tuning companies could remove the EVAP elements from the code on the generic maps but for some reason not the SAI?

I hope I'm not covering old ground here, but just wanted to jot my current knowledge down as I've spent literally ages trawling numerous different threads and had yet to find a single post that brought some of the above elements together in one place.

I also hope to add to this first post as more facts emerge and hopefully post my own SAI specific DIY for reference (i.e. not as part of the bigger vacuum system delete in case others don't want to tackle it all at once).

In the meantime any thoughts or help appreciated. 

[Dalo Harkin]

I removed my SAI and fitted the blanking plate and a resistor, my engine is the ARZ and I didn't get a CEL.

If I were you, I would cut the SAI connector (leaving enough on them to reconnect should you need to) and then connect the resistors in place with terminal strip, if you get a CEL just reconnect the SAI or reconnect it when it comes to MOT time

[LR5V]

I removed my SAI and fitted the blanking plate and a resistor, my engine is the AUM and I get a CEL after 2 days.

Needs to be coded out of the management

[OSR]

Thanks for the replies guys, interesting to see a split already between the ARZ and AUM camps.

I took the engine covers off and removed the short bit of SAI hose (the bit about 6" long that makes up the final connection to the PCV valve) to see what happens. Drove around a bit today but the car was already warm so wasn't trying to run the SAI on startup. Going to move the car tonight so will see what happens when it's cold - I'm assuming the first time I start up and the SAI tries to run it will ping the CEL.

Will keep you posted, something must trigger the code as it seems a bit random if it just appears after 2 days?

[OSR]

Started the car and SAI pump kicked in - sounded rough for about 30secs then seemed to sort itself out. Only drove up the road and back but no CEL as of yet.

[OSR]

Update from today's efforts - hoses and pump removed and resistor fitted. Can't believe how much space it all used to take up - looks a lot neater in the bay now and should make access to various bits and bobs easier (like the oil filter!). I've left the PCV valve (I think that's what it's called?) on the air filer side of the engine block for now as I didn't want to be draining coolant today.

CEL came on as warned after about 10 miles of driving but did a quick scan with my code reader and got P0411 (16795) - SAI system incorrect flow detected. Cleared the code and drove home and no CEL as of yet. I've also cleared the odometer to see if there's a magic number for when it reappears.

[LR5V]

Yes - I get the same error.
Pretty sure its not mileage that determines it
the SAI system only operates at engine start, it comes back after a set number of starts, each time it logs the fault.
Not sure why it seems to take 1-2 days on mine for the check light to come on.

[OSR]

Yeah it's a strange one - when I drove mine last weekend for the first time since pump removal the CEL didn't come on until after about 10miles of driving, which I thought was weird as I would expect the ECU to throw the fault at the time when it thinks the SAI pump is running?

Having said that I've had my suspicions about my SAI system for a while as it often comes on in short bursts after a few miles/minutes of driving but I guess this could just be down to it detecting that the car has still not fully warmed up and switches the pump back on to compensate?

This weekend I'm going to drain the coolant and remove the hardware from the engine block adjacent to the coolant flange - also need to remove that pair of vacuum hardlines while I'm at it as they've been sitting there redundant since I did my N249 bypass years ago 

[topher]

generally the ARZs won't ping the EML but may store a fault code, AUMs will put the light on randomly every few days/weeks as the ECU does its calculations. Won't be any trouble on an MOT emissions test though that has to be done with a fully warmed up engine.

[LR5V]

generally the ARZs won't ping the EML but may store a fault code, AUMs will put the light on randomly every few days/weeks as the ECU does its calculations. Won't be any trouble on an MOT emissions test though that has to be done with a fully warmed up engine.

Despite mine taking at least a day to show the check light, to ensure no issue in the test -i have for the Last 2 MOT's cleared the fault in the test station car park using vagcom on a netbook.
Its a bit of a pita, but I am hoping to get this mapped out soon by someone handy with remapping ecu's