1998 V70 Does the Air Pump Actually Do Anything?

[xHeart]

It tells me "need" is still there, only the "source/method" was changed... from SAS to VVT.

What source/method was used before the introduction of air pump (sas)?

[jblackburn]

It tells me "need" is still there, only the "source/method" was changed... from SAS to VVT.

What source/method was used before the introduction of air pump (sas)?

EGR.

Smog pumps were used back into the late 70's/80's as well.

[cn90]

jblackburn,

Thanks for info.
Over the years I hated that air pump business: spending too much time troubleshooting etc. etc., only to end up with the 90-cent diode lol...

[erikv11]

Ah, I see what you are asking xHeart. I meant that preheating the cat by smog pump or other means does not improve vehicle operation, so in that sense it is in no way "necessary" for cars in snow country. There is no "need" for it, the vehicle will run just fine with or without one, it doesn't matter.

A clear argument that there is no "need" for the air pump is that anecdotally, about half of the 96-98's came with an air pump and half didn't. That figure is based on the sample size of the four snow country vehicles that I have owned personally, but you get the idea.

[jblackburn]

A clear argument that there is no "need" for the air pump is that anecdotally, about half of the 96-98's came with an air pump and half didn't. That figure is based on the sample size of the four snow country vehicles that I have owned personally, but you get the idea.

I'm curious as to how they determine/distribute what car comes with what for the 850's. You'd think they'd just make them all the same for the late-96/97 model year or something.

Then again, here in VA, we looked at 2 identical new cars at the same dealer, one California-emissions, and one non-California.

[MrAl]

Hi,

Very interesting information in this thread, both for when we have the air pump and when we might eliminate it. I had been playing around with mine for about 2 months now and so i have a vested interest in this subject area too.

First, to add a little information that i got from this forum, the vacuum valve at the back of the engine might get stuck open and destroy the expensive air pump because condensation can get into the air pump where it becomes water, and the water gets into the motor where it can oxidize the commutator and therefore raise the series resistance of the motor which then means 12v can no longer provide enough current to start the motor, and also rust the bearings and i think even deposit debris inside. With a small hole drilled in the bottom the water leaks out so can not build up over time and ruin the guts. For mine it took about 2 months and it was damaged, because the vacuum valve was faulty. I thought i had more time than that, but that was just silly. I should have replaced the valve at the same time as the pump, or at the very least checked the valve for leakage. At the time though i didnt know any better, and could not get the valve off because of the hose clamps that were the crimp on kind. Since then i've done more, but that was a nasty lesson to learn. I was, and still am, a little shy about fooling with the ECU since i dont know much about that yet, and i hate fooling with circuits i dont know everything about even though i've worked with circuits for maybe 40 or more years now. Maybe that taught me that you shouldnt modify anything unless you know all of the ramifications, both current and future, and some of the future consequences can be very very hard to analyze beforehand, knowing that engineers took years to figure some things out. On the other hand, this ECU trick seems very well tested and proved, so i guess it is an option, and i would not recommend doing it except for the fact that some of exact same cars where shipped with it and some without it, without any consequences, and that doesnt surprise me because it only comes on for a little while and so that can not possibly reduce emissions by any significant factor. I have a feeling that the whole system was due to a technicality that could not be simply ignored, even though it had very very little effect on any true emissions test (measurement of exhaust directly).

That said, testing the pump is quite simple. Simply disconnect the connector (pull it apart maybe after releasing the tab with a screwdriver) and attach a set of jumper leads with alligator clips on both ends. This jumper will have two leads and four alligator clips.
Placing the positive lead on the non-black wire (blue on mine) connector prong and the negative lead on the black wire connector prong, then connecting the other two alligator clips at the other end of the jumper to positive and negative of the battery respectively, the pump should start running. There's no doubt you will hear it if it runs. If it doesnt run, it could be frozen or just a little frozen and the commutator is oxidized.
There is a small catch to this test. That is, if the motor is shorted (not sure if this can happen with this motor, but in general it is always a possibility that something can be shorted inside the case) so you may want to use a small value power resistor in series with one of the jumper leads, or else just connect the positive lead to the battery and quickly touch the remaining negative lead to the negative lead of the battery and remove it, listening for any noise from the air pump. If it sounds like it is groaning a little that means it is probably not shorted. If you dont hear any sound it could be damaged or shorted, so be careful as the jumper leads will heat up fast and melt if the connection is left for more than about 1 second. That's why a small value series resistor is a good idea, to prevent lead heating if something inside the case is shorted. It is most likely not shorted, but you never know because you cant see inside there. A suitable resistor is 1 Ohm, 50 watts.

Another catch is that the pump motor is only rated for intermittent duty, so if it runs for too long it will burn up the motor and maybe even melt the case. For the test though, it only has to run for a few seconds, just to make sure the armature can still turn with a 12v battery source.
If you ever hear it start and not stop, it would probably be best to pull the relay until you can get it fixed, because that means the motor will burn up. I dont know if this can happen, but if it does, pull the relay out

Hope this helps a little anyway.