SAI not working on AUM?

[Waffs1984]

So my SAI used to make a bit of a racket (like a big fan type noise) on startup for approx 1-2mins. The last few times i've driven the car its not been doing this. Scanned for codes and i get nothing other than the infamous 17705 

Now as i understand it the SAI is simply to "warm" the CAT up on startup to preserve its life? The AUM was the only mk4 fitted with the SAI IIRC and other models such as the AGU don't have this system so it shouldn't cause me any problems other that its annoying me coz it used to work and now it don't?

[barry-gti]

The Anni was also fitted with it

You can remove it and put a resistor in place to fool the ECU into thinking it's there...

Or... i have one 

[Waffs1984]

Yeah i seem to recall someone (i think it was you Barry?) who stripped the SAI system off the car but had issues afterwards? I know Forge sell a blanking plate which is a simple looking oval plate with two bolts?

Is there a lot to the SAI system, i.e. is it a big job to strip out? The only bit i know off off the top of my head is the corrugated black plastic pipe that runs accross the front of the engine, never really paid attention to where it goes! 

[barry-gti]

yeah I put an AGU in where my AUM was. But, the ECU was obviously still trying to use the SAI which doesn't go on the AGU. i'm not sure what you use to blank off where it goes but I think the resistor was 10W 330ohms... I Might be wrong, I reccomend asking Topher...

There's not alot too it really, there's the corregated pipe and a Pump. a couple wires where it plugs in...

[topher]

if it's not working and the only code you're getting is 17705 it is probably just a leak/split in one of the hoses around the N112 valve (next to the n249 by the dipstick). Or with vagcom use the output tests to see if you can fire up the SAI pump manually.

[RTechUK]

So my SAI used to make a bit of a racket (like a big fan type noise) on startup for approx 1-2mins. The last few times i've driven the car its not been doing this. Scanned for codes and i get nothing other than the infamous 17705 

Now as i understand it the SAI is simply to "warm" the CAT up on startup to preserve its life? The AUM was the only mk4 fitted with the SAI IIRC and other models such as the AGU don't have this system so it shouldn't cause me any problems other that its annoying me coz it used to work and now it don't?

You should have no issues with the SAI pump not working, on cold start the ecu runs a slightly richer lambda, the SAI pumps air into the exhaust manifold tract and this air helps keep the emissions down and by chemical reaction helps warm the cat. 

If I was you I would ditch it all, remove the pump, combi valve and use the forge blanking plate.  RS componests sell the resistors for around £2 each and the forge blanking plate is about £12.  If you can get the car up here to us, we will give is a smoke test and check the 17705 fault out for you, we have found the  17705 can be related to issues with start up temps and can be a "fake code", which we can easy fix in the mapping, stock or tuned map.     
Nick

[Waffs1984]

Cheers for the replies guys.

The 17705 code i've been getting since i owned the car and have been in the process of replacing boost/vacuum hoses in an attempt to get rid of it but as we all know it is a code that plagues many 1.8T's and is a bugger to get rid of!

As for pipes down by the N112 & N249 i replaced all of these with silicone when i did the N249 bypass so i'm fairly confident there's no leaks there. I've also simplified the PCV system when i fitted my catch can so again a lot of the original pipework has been replaced.

I still have a boost hose kit on my list and i have a sneaky feeling the pipe between the throttle body and the pancake pipe has a habit of leaking does it not?

As for testing the SAI i don't have a full version of Vagcom, just a handheld code reader. Would there be a way of testing the SAI pump without Vagcom?

[Waffs1984]

Ah Nick you got a post inbetween me replying!

Yeah as long as it makes no difference to the running of the car i'm not particularly worried about the SAI. As for the 17705 i may well pop up to you guys to try and get it sorted once and for all but i'll probably wait until i have something bigger to have fitted (Cat back, big brakes and VR6/G60 clutch/flywheel are all on my list  ) and then just do the one trip. I currently drive less than 5 miles a week lol which is why i've been going through the car with a fine tooth comb trying to iron out all the issues!

[RTechUK]

Ah Nick you got a post inbetween me replying!

Yeah as long as it makes no difference to the running of the car i'm not particularly worried about the SAI. As for the 17705 i may well pop up to you guys to try and get it sorted once and for all but i'll probably wait until i have something bigger to have fitted (Cat back, big brakes and VR6/G60 clutch/flywheel are all on my list  ) and then just do the one trip. I currently drive less than 5 miles a week lol which is why i've been going through the car with a fine tooth comb trying to iron out all the issues!

I am 100% sure I can get to the end of the 17705 fault for you,

[Waffs1984]

I am 100% sure I can get to the end of the 17705 fault for you,

Cheers Nick, i'll get my ass in gear and get some cash together, i'm thinking a Milltek cat-back and a smoke test