1996 850 Dust in Airbox from SAS?

Post by **atucker1** » 05 Jan 2018, 17:29

Hi everyone, thanks in advance for the help.
My mom's 1996 850 NA starting stalling when shifted into gear and other times under little load (sitting in the parking lot). Guessing it might be a MAF sensor problem, I opened up the airbox. The entire airbox was coated with a very fine, rust colored brown dust. The air filter had ripped through and looked to be slightly burned/melted as well, and the MAF sensor was completely coated. I cleaned out the airbox, replaced the filter, cleaned the MAF, and the problem seemed better. However, a few weeks later, the same symptoms returned. Opening up the airbox again, there was more dust, which appeared to be coming from the SAS hose attached to the front of the airbox. Throughout the entire episode, the CEL only came on momentarily once or twice, but went off (and no codes were able to be read). Has anyone heard of an SAS pump failure resulting in rust/rusty water being spewed into the airbox? This seems like the most logical explanation since I know that the pumps usually fail when exhaust gases condense inside and corrode them. Or, is there another possible explanation? At this point, I am planning to replace the MAF sensor and cap off the SAS hose. Is it necessary to remove the physical SAS components or can I just cap off the port on the airbox and the hose connecting to the airbox and leave it hanging? I understand that the CEL will stay on unless I modify the ECU as well-documented elsewhere. Thanks for your advice!

(Pictures of airbox and intake attached, powder appears yellow in pictures but is really rust-brown.)

Post by **bmdubya1198** » 05 Jan 2018, 17:53

That is just gross... it looks like the filter was burned.
I don't think I've ever seen this happen from the SAS pump, but I would say that's where it's coming from. Pull off the hose from the pump side and see if there is any of that rusty yellow crap in there.
I'm pretty sure (but not 100% positive) you can remove the whole pump and everything and just cap off the air box. As you said, you'll have a CEL until you do the ECU diode mod.

Post by **misha** » 05 Jan 2018, 17:56

Yes...it is from failed sas valve.I had this a long time ago...but mine just spewed water(actually...the engine inhaled the water) from condensation in airbox and maf.
You need to cap the side of the hose which goes from sas valve to airbox,to cap the inlet for that hose at airbox itself and also to cap vacuum lines.
The best solution is to remove the sas valve completely from exhaust manifold and to block the outlet hole with a proper screw.That's what i did.

If Maf survived,you need to clean it with a maf cleaner ONLY without even touching the element.Just spray it carefully and let it dry good before install it back.
If it survived(which would be a miracle),the only problem you will have is check engine light for sas system.

That check engine light episode was because the engine misfired from inhaled water into cylinders and cel probably flashed few times before it turned off.

You also need to cut the power for air pump.There is a relay like the big one on cooling fan carrier under the hood...except this one is under the driver's side fender,just besides air pump.Cut it's red wire to disable the positive line and you're done.Access is from below.

Don't forget to reset ecu and fuel trim by disconnecting negative battery cable for 10-15min after you finish that phisycal sas delete and to install new air filter.

Post by **abscate** » 05 Jan 2018, 20:17

You can drill a hole in the pump assembly to let that water out. See threads.

Post by **atucker1** » 12 May 2019, 07:56

Update in case anyone had the same issue:

Pulled off the SAS hose from the airbox and plugged the port. Currently just clamped off the SAS hose so it can't spit dust into the engine bay, although I may need to make it its own little intake when emissions testing comes around. I tried cleaning the MAF but ended up buying a new one. Telltale sign of the MAF failure is that unplugging the MAF connector while the car was running led to improvement in idle, plugging it back in killed the engine. Since I replaced the MAF and airfilter and clamped off the SAS hose, the car has been running great!

Post by **abscate** » 12 May 2019, 09:03

Telltale sign of the MAF failure is that unplugging the MAF connector while the car was running led to improvement in idle, plugging it back in killed the engine

You cannot test a MAF with this method, as it part of a more complicated closed loop feedback system

Post by **erikv11** » 12 May 2019, 16:00

abscate wrote: ↑12 May 2019, 09:03
Telltale sign of the MAF failure is that unplugging the MAF connector while the car was running led to improvement in idle, plugging it back in killed the engine
You cannot test a MAF with this method, as it part of a more complicated closed loop feedback system

Except that this is a very reliable test, when the test gives the outputs described by OP.

OP - much better to not do the plugging and unplugging while the engine is running. Shut off the car first. Hopefully the new MAF is Bosch, or it will fail soon.