[1997 Volvo 850 GLT] Air Pump Runs-w/Car Off-Kills Battery

Post by **1997volvo850** » 10 Nov 2014, 07:35

For the most part my 1997 Volvo 850 GLT was running fine until I parked the car on Friday night.

On Saturday morning my car wouldn't start. The battery was dead - read 0.08 volts in place.
Upon remove the battery my charger was able to charge the battery just fine. Battery is only a year old
and appears to be ok though I'm not sure what type of damage running it down this far does.

I installed another charged battery and the air pump immediately fires up with its signature whining
noise. I'm actually able to start the car but the engine runs very rough and stalls in less than a minute.
One thought is to drive it to my Volvo mechanic several blocks away.

It is my understanding that the common causes of the air pump running continuously are 1) the air
pump relay attached to the air pump is stuck closed or 2) the temperature sensor needs to be replaced.
Any sense of which problem occurs most frequently? Does the exposed location of the air pump relay
result in frequent failures?

In any case I am planning to replace the air pump relay. If this fails I'm planning to take it to my nearby
Volvo mechanic.

Since the car stalls I'm debating whether to attempt to drive the car or have it towed. One question is
whether there is something I can do (like disable the air pump?) that would make the car drivable for a
short distance. I don't want to stall in traffic and have an accident. Will disabling the air pump help with
the rough running / stalling problem?

There are some older threads I ran into on the air pump issue but the pictures are no longer viewable. I'm trying to remember how much of a pain it is to replace the air pump relay.

Thanks,
David

Post by **erikv11** » 10 Nov 2014, 09:12

A good way to troubleshoot here is to simply unplug the air pump. The ECU will set a code for the SAS but you can clear that later. Totally safe to drive without an air pump, the majority of Volvos in these years plagued by air pumps have broken ones now anyway!

I don't think a bad ECT sensor will run the air pump, it's the cooling fan that can come on in that case. You're sure it's the air pump right? Because the other symptoms would be consistent with a bad ECT. Unplugging the air pump can help you figure it out.

Post by **1997volvo850** » 10 Nov 2014, 17:01

Thanks.

I replaced the air pump on my other 850 so I'm pretty sure its the air pump. Sound is coming from
beneath battery area. The cooling fan is definitely not coming on.

So basically unplug air pump from relay and see if car runs better. There are three plugs attached
to relay - I take it unplugging either left or right connector will work.

If it does run better then is a new relay the next thing to try? Or are there other reasons the
air pump might stay on? (something other than relay?) Just wondering if relay is problem 99% of time.

I will try unplugging the air pump and report back. Car is out of town so will try tomorrow morning.
Trying to collect as much information as possible before I go on rescue mission.

Post by **rmmagow** » 10 Nov 2014, 17:37

I bet you could touch the relay and see if it's hot. Probably stuck on. Be careful, could be real hot.

Post by **cn90** » 10 Nov 2014, 17:46

SAS Relay is stuck in "on" position.

SAS system has nothing to do with ECT sensor.

I suggest that you remove the SAS relay, do the diode mod (90-cent diode from Radio Shack) and say the last good bye to the SAS system.

Post by **jreed** » 11 Nov 2014, 05:15

I had the same problem on my 97 855 GLT about four or five years ago... the relay stuck in the on position and ran the air pump until the battery ran down. I replaced the relay with a KAE brand aftermarket relay from FCP or IPD, and it has been working fine since then.

Post by **erikv11** » 11 Nov 2014, 08:02

There is no question the relay is stuck, since indeed the air pump is on. The peculiar thing in this one is, if it is coupled to the car stalling out.

Post by **1997volvo850** » 12 Nov 2014, 11:59

Update: I unplugged the air pump and the whining sound has disappeared when I connect the battery.
Sounds like the air pump relay is stuck. The question now is whether not having the air pump connected
results in a very rough running engine.

I'm able to start the car but the idle is all over the place and the car stalls if I don't press the gas.

Once the car warms up the idle stabilizes. I take a previous comment to imply that running without the
air pump should not result in the rough idling/stalling that I'm experiences. The idle all-over-the place
almost reminds me of previous problems with idle air control valve.

The only code I read was related to the air pump being disabled.

Any help is appreciated.

PS: I'm able to reach the air pump relay from underneath the car but it's not clear whether I can remove
it and install a new one from below. Seems I should be able to but I'm not familiar with how it is attached
and the motion/direction of force to remove it. When I replaced the air pump on my other 850 I recall
coming down from above after removing battery/tray. Unfortunately the pictures in the older threads related to air pumps are not longer available.

Post by **jblackburn** » 12 Nov 2014, 13:10

1997volvo850 wrote:Update: I unplugged the air pump and the whining sound has disappeared when I connect the battery.
Sounds like the air pump relay is stuck. The question now is whether not having the air pump connected
results in a very rough running engine.

I'm able to start the car but the idle is all over the place and the car stalls if I don't press the gas.

Once the car warms up the idle stabilizes. I take a previous comment to imply that running without the
air pump should not result in the rough idling/stalling that I'm experiences. The idle all-over-the place
almost reminds me of previous problems with idle air control valve.

The only code I read was related to the air pump being disabled.

Any help is appreciated.

PS: I'm able to reach the air pump relay from underneath the car but it's not clear whether I can remove
it and install a new one from below. Seems I should be able to but I'm not familiar with how it is attached
and the motion/direction of force to remove it. When I replaced the air pump on my other 850 I recall
coming down from above after removing battery/tray. Unfortunately the pictures in the older threads related to air pumps are not longer available.

Try this.

https://www.matthewsvolvosite.com/forums ... =1&t=31536

The air pump directs air upstream of the first O2 sensor, so if the car thinks that the pump is running, it may be expecting different values @ the O2 sensor.

Post by **1997volvo850** » 19 Nov 2014, 15:07

Update: the idle seems normal now. The rough running that started when I disconnected the
air pump has disappeared .

At this point popping in a new relay seems to make sense. The only question I have now is how to
remove the relay from below the car. Many of the pictures associated with previous threads on
air pump issues are no longer available. I'm looking for a picture of the mount the air pump relay attaches
to so I can see how to remove it. I'd prefer not to break it off just to figure this out. I'm assuming I
can replace the relay from below.

Thanks