Bought a rebuilt smog pump,and I don't think the clutch is engaging.Every morning and every night when I start the car I never see the clutch engage.Since I don't know what prompts it to engage I don't know what to check. If i unplug the pump will is there always power to the pump? How can I findout if the problem is the pump?

Pretty sure the pump engages for a bit on startup and thats pretty much it. I have mine disable (belt) but still here the clutch engage. I am sure others know more on the details of operation. Maybe its tripped by the purge vacuum?

Want mine?

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1991 560 SEL / 185k miles
1992 750il / 17k miles - project car

Mine engages on cold startup.

Define (cold startup).The average Temp. Is about 50.

Why / how do you feel scammed?

Why was the pump changed?

Did you test the wiring for power prior to changing the pump?

Did you test the wiring for power after the pump change?

Did you apply 12V to the clutch to see if it engages?

My 97 has a electric air pump. It typically runs for 60 sec at start up to provide extra oxygen to the exhaust and sometimes runs for a few seconds after coming to a stop.

Also, most have a upshift delay when cold to get the car converters warmed up.

After four or more hours of sitting.

OK Thanks

The pump was replaced because to original had a bad noisy Bering. And no I did not put 12 volts to the new pump,but I will. Thanks

I believe the power will always be there, but the engine control unit (I believe) provides the ground when the pump is supposed to be running.

If the old pump ran but was noisy you would assume the new pump should also run. You could have had a bad bearing on the old one which means it was noisy all the time, not just when it was running, so you should clarify that.

I think it's a bit much saying you were scammed. If you have new pump which was bad maybe whoever sold it will send you a replacement, to say you were scammed at this point is irresponsible.

Gilly

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Well scammed is a little HARCH,but my anger really comes from the fact that removing the old one was very,very difficult and took about 3 Hrs.Removing the long bolt that holds the pump to the housing would not come out. So when i finally got it off and installed the rebuilt on and it did not work,i was very disappointed.BTW: The old pump only made noise when the clutch was engaged.I took the car to Donny [Benzmac] about 4Yrs ago and he just unplugged it.How should i put 12volts to the pump? Can i just attach 2 wires to the battery and stick the other ends to the pump?

Yes, in fact usually even a 9V battery touched to the pins will engage the clutch, no need to run lines to the battery.

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OK: The clutch engaged when adding 12 volts. So i guess the pump is ok.Checked if power is comming out of the plug and nothing.Now what?

Problem Solved: Pulled plug apart and cleaned both male and female parts and the clutch engaged. A BIG THANKS to all of you guys for your help.

We aim to please

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