cheese

1997 base model 986. 3 days ago on startup, turned on a/c because it is very hot in the south in August. A smell like a burnt electric motor winding was accompanied by the heater blower circuit fuse opening. Replaced 30 amp fuse but now getting cel. A/c blower works but not SAI blower. Took out SAI and blew it out with air, general cleaning and test with 12vdc supply. It ran with no problems ($1800 cost savings!). Now to find why there is no voltage to SAI on startup.

Macster

My knowledge of the SAI system is limited but I recall there's an electrically controlled valve which if I'm right might have fried and been the source of the smell.

But how this can explain the reason why the SAI pump works when powered directly but doesn't work in the car I can't say.

Oh, another thing. It has been my experience the infrequent times I do this that if I start the engine and I hear the SAI pump run and then have to shut the engine off upon a restart -- unless I leave the engine off a time -- the SAI pump does not run upon this subsequent restart.

My point is do not let the possibility the pump is not getting any power because that is the way things work arising from your testing the SAI system.

A tech can command the SAI pump to come on using a diagnostics computer but you can't. Thus you have to rely upon some time expiring if you are starting the engine then turning it off and restarting it in a short amount of time.

Sincerely,

Macster.

cheese

Thank you Macster. As it turns out, the 40 amp Maxi fuse in the rear relay station was open. It appears it opened due to ambient high heat because very little arcing was evident, and after all the fuse was 15 years old. The fuse element looks a little oxidized too. After replacing the fuse, the SAI pump runs as always, only perhaps a bit quieter. My potential for a very expensive repair became a less than $5 fix. Boxsters are indeed beautiful!

Mighty Shilling

Pardon my ignorance, I'm new to Boxsters. What's an SAI? I'm gonna take a stab, secondary air injection?

How common is it for this part to fail?

Macster

SAI in this context is indeed secondary air injection, which refers in this case to the entire system.

Overall the system is pretty robust. As is to be expected with a large enough population of cars there have been a few SAI components fail.

The pump is probably the component of this system that most often fails, but even so not frequently enough to lose any sleep over.

All you can do is listen to the thing when you first start the engine and verify it comes on and it sounds like it always sounds.

If it doesn't come on, and it should most of the time, but there are times when it may not come on so you have to be aware of this and don't mistake this for a problem, or if its sound is different this time compared to previous times or changes notably while running this time, then you can worry.

Sincerely,

Macster.

Mighty Shilling

Cool. thanks! the SAI pump on my 540i sounds like a vacuum cleaner at startup. very easy to tell when it's running.