Confirmation regarding the (non-)use of the SAI

[wvg_beetle]

Guys,

I am an absolute beginner when it comes down to car engines, so forgive me for my questions But I need some expert advice here as I get sick from the stealership (like that word!) with their mumbo-jumbo potato regarding my beetle. I just want plain answers to simple questions and they are running around the bush. Or maybe running around their money And yes, I am reading Autorepair for Dummies (I really do!), but that is still pretty basic.

I have a VW Beetle (2001) with an 1.8 Turbo Engine. Apparently the Secondary Air Pump makes a lot of noise (according to the mechanic) and needs to be replaced. Well, that is quite some money for a new SAI...

I have read the different posts on this forum and my questions are:
1/ What is the purpose of the SAI in the first place? From what I figure (from the forums): it has to do with the emissions; especially in cold weather conditions. So, why is the primary air pump not enough?

2/ The whinning noise of the SAI might have to do with the bolts/rivets rather than that the SAI is faulty. Right?

3/ Most important: can the engine run without the SAI? From what I figure, the answer is 'Yes', but the CEL may be on all the time on the dashboard, making it more difficult to initially identify a real engine problem.

If somebody can just answer these questions with straightforward answers, I would appreciate that!

Thx and keep up the good work!
WVG

[noR]

1) Something about thinning out the air/fuel ratio to adjust the temperature of your exhaust I think? I really don't know for sure. And I don't think a 'primary air pump' exists, maybe they're talking about pistons doing that?

2) yes, it's air escaping through the cracks in the pump. A very simple fix if you can get to them.

3) you are correct. Some aftermarket chips have programming to allow this to be removed w/o causing a code, but that's more along the lines of custom work. Was it unitronic? I think I've only heard of 1 programming company that could enable this ability.

[LadybugEwa]

what about the easy fix, i.e., replacing the rivets on the SAI?

[wvg_beetle]

Ad 1/ Well, there must be an air pump somewhere, I think, in order to get air into the cylinders? That's why I was talking about a primary air pump, whose function is to get air, filter it and pass it through to the cylinders/piston chambers. But I may be wrong

[wvg_beetle]

Good point. Will ask my mechanic how difficult/easy it is to do this fix.

But just want to make sure that I can run without the SAI if it turns out that the SAI is faulty and needs to be replaced.

[zeusenergy]

Originally Posted by wvg_beetle

Guys,

I am an absolute beginner when it comes down to car engines, so forgive me for my questions But I need some expert advice here as I get sick from the stealership (like that word!) with their mumbo-jumbo bullsh!t regarding my beetle. I just want plain answers to simple questions and they are running around the bush. Or maybe running around their money And yes, I am reading Autorepair for Dummies (I really do!), but that is still pretty basic.

I have a VW Beetle (2001) with an 1.8 Turbo Engine. Apparently the Secondary Air Pump makes a lot of noise (according to the mechanic) and needs to be replaced. Well, that is quite some money for a new SAI...

I have read the different posts on this forum and my questions are:
1/ What is the purpose of the SAI in the first place? From what I figure (from the forums): it has to do with the emissions; especially in cold weather conditions. So, why is the primary air pump not enough?

2/ The whinning noise of the SAI might have to do with the bolts/rivets rather than that the SAI is faulty. Right?

3/ Most important: can the engine run without the SAI? From what I figure, the answer is 'Yes', but the CEL may be on all the time on the dashboard, making it more difficult to initially identify a real engine problem.

If somebody can just answer these questions with straightforward answers, I would appreciate that!

Thx and keep up the good work!
WVG

I got all your answers right here....

The SAI is Secondary Air Injection. It provides a small volume of air to the area behind the exhaust valves to help heat up the catalyst earlier, and make cold emissions better. The N112 (see 4 below) (small solenoid valve under engine cover, to left of air bladder assembly over the spark plugs) is energized which opens the Combi valve (2) attached to the head. The SAIP (SAI pump) (13) is also energized at this time and begins pumping air into the Combi valve, which passes to the exhaust stream. All of this happens for about 90 seconds on cold startup, and once more after idle is hit once again. The SAIP on our cars may not have the rivets as in other VAG cars such as the GTI's, mine looks different than what I have seen online. Some of the MK4 guys will remove the SAIP and bypass the wiring with a resistor and also do the same with a resistor on the N112 wiring too, then get a blockoff plate and remove the Combi valve. You will get a CEL from this mod and the only way to permanently get rid of it is with custom programming with a chip. You CAN run without the pump, and reinstall it before going to reinspect the car if you don't care about a CEL, it does nothing to prevent the car's normal operation unless you don't install a resistor and disconnect the N112 vaccuum line. The vacuum line attached with no SAIP will allow exhaust to backflow out of the Combi. With no resistor on the SAIP harness, you could lose adaptation and run in a protected low performance mode.

Your best bet is to decide how involved you want to get. If you don't care about the noise, then just leave it alone. VW is trying to get you to spend some cake for service. If you don't mind a little DIY work, then head over to vwvortex.com and check out the saip delete DIY for more involved discussion about what to expect. I will wait to see if you are interested in this mod and can hook you up with all the schematics and info pertaining with the mod on our beetles, it's quite different than the MK4.
BTW, the "primary" air pump is the cycling of the engine itelf, it's a giant "pump" in and of itself. It is enough, but during cold state the cat isn't very efficient, therefore VW included the SAI system to help cold emissions....


Here's a small exploded view from the bentley manual, the pump lives under your intake manifold:

[bugasm99]

not sure if the part numbers on the 2.0 and the 1.8T are the same for an air pump, but I have one just collecting dust in my shed for some time if you do end up needing to replace it.

[wvg_beetle]

Hi ZeusEnergy!

Thanks for taking the time for this detailed (and clear!) explanation. The pieces of the puzzle are coming together now and I will look for a mechanic (who definitely will not be working for a VW stealership) and discuss with him the following options:
(i) Take a look at the rivets and try to 'fix them' to reduce the noise.

(ii) If (i) does not help, disconnect the electricity cable (no. 5 in the picture - well, it looks like a cable from the SAI. So, we leave the SAI in the car, but it simply does not work but can be hooked up any time if needed (e.g., for inspection).

(iii) Will discuss the programming of the chip to get ride of the CEL. If that is too expensive or he looks at me like I told him that I came directly from Mars , I will live with the CEL or may find an expert to do this.

Maybe in the future, when I come across a 2nd-hand and reliable SAI, I may try to get it replaced. But for the moment, I don't have a problem to live without it as long as my engine can, which is the case. Reason (if you might wonder) is pure financial

Thanks again!
WVG

[wvg_beetle]

Hi Bugasm99.

Thanks for the reply.
Q1: Can you send me the specifications/specifics/part number of the SAI which you have? I can ask my mechanic whether it would fit.

Q2: Your SAI is from an VW 2.0 engine? I guess so..
Thanks!
WVG

[zeusenergy]

Originally Posted by wvg_beetle

Hi ZeusEnergy!

Thanks for taking the time for this detailed (and clear!) explanation. The pieces of the puzzle are coming together now and I will look for a mechanic (who definitely will not be working for a VW stealership) and discuss with him the following options:
(i) Take a look at the rivets and try to 'fix them' to reduce the noise.

(ii) If (i) does not help, disconnect the electricity cable (no. 5 in the picture - well, it looks like a cable from the SAI. So, we leave the SAI in the car, but it simply does not work but can be hooked up any time if needed (e.g., for inspection).

(iii) Will discuss the programming of the chip to get ride of the CEL. If that is too expensive or he looks at me like I told him that I came directly from Mars , I will live with the CEL or may find an expert to do this.

Maybe in the future, when I come across a 2nd-hand and reliable SAI, I may try to get it replaced. But for the moment, I don't have a problem to live without it as long as my engine can, which is the case. Reason (if you might wonder) is pure financial

Thanks again!
WVG

Disconnecting the electrical cable will work, so long as you attach the appropriate resistor to the line in place of the SAIP motor. Otherwise, your engine will NOT run right. The resistor will cost less than $5 and can be installed by anyone capable of soldering and crimping a few pieces together. If this is your choice, than I can give you the instructions to do this and the exact parts you will need.

Fixing the rivets again may not work, since I have not seen a single rivet holding our pumps together yet- unless yours looks different than the one in the diagram above.

Programming the chip can only be done for $500+ and it will also allow you to get big horsepower out of the engine as an INTENDED side effect! Sounds like this isn't really an option though.

Your welcome, and let me know if I can help any further.

[wvg_beetle]

Hi!

Thanks again. Yes, I would be interested to see/know more about the resistor & diagram. Not sure whether I will do it myself, but I can show the mechanic and ask whether he/she can do it.

One question about the resistor: if the SAI is attached and the electrical cable is unplugged, why is a resistor needed? Is it because the engine/battery/... is feeding the electrical cable with energy, but the energy doesn't go anywhere (as the cable is unplugged) and may still do harm then?
Thanks!

[bugasm99]

Originally Posted by wvg_beetle

Hi Bugasm99.

Thanks for the reply.
Q1: Can you send me the specifications/specifics/part number of the SAI which you have? I can ask my mechanic whether it would fit.

Q2: Your SAI is from an VW 2.0 engine? I guess so..
Thanks!
WVG

sorry, just saw this. I will get you the part number tonight. Also, i have about 15 of the resistors if you need one. Had to buy in a pack of 20.

As for the resistor, even if you add a resistor when removing the pump, you will still throw a check engine light. The ecu checks for a signal change at the o2 sensor when the pump kicks on, if it does not see this change it will throw a code for "incorrect flow". Ask how I know.

You also cannot code this pump out. The Air pump is coded into the hard coding for the ecu, not the management file. So you would actually need an ecu from a non air pump car (which I am not sure if this existed in 1.8T's).

[bugasm99]

Originally Posted by zeusenergy

Fixing the rivets again may not work, since I have not seen a single rivet holding our pumps together yet- unless yours looks different than the one in the diagram above.

There are rivets that circle the pump ... much like the bolts that would hold the compressor housing on a turbo.

[LadybugEwa]

Originally Posted by bugasm99

There are rivets that circle the pump ... much like the bolts that would hold the compressor housing on a turbo.

that's just what I meant

[bugasm99]

i wrote down the part#, and then forgot the paper. But I believe it was 06A 959 253. The red numbers are the ones I am not definite on.

[zeusenergy]

Originally Posted by bugasm99

There are rivets that circle the pump ... much like the bolts that would hold the compressor housing on a turbo.

Hmmm mine looks pressed together, nearly no flange room at all for rivets. But then I haven't removed the pump yet.

OP: The resistor is a 330 OHM, 10 Watt part. It has a built in heatsink. You can just apply that to the harness wires and you no longer need the pump, although like bugasm said, you will toss a code. If you leave it unplugged from anything, the ECM will notice it's not there anymore. That makes the ECM want to run the car in a "protected mode" and throw a code. If the resistor is plugged in, but the SAI flow is not happening, the ECM will just throw a code for emissions, not performance.
Bugasm is right on the software flashes, I think the only way to remove SAIp from the check is big turbo software. There are some guys that have it done and the SAIP is no longer a part of the equation, but of course their cars are extreme customs running huge turbos twice the size of the stock ones.