Yet another airpump problem
 

So I'm on my 3rd airpump. The first two failed due to bad bearings. Now my current one has stopped working -- the clutch isn't engaging. There is +13.6V at the terminals to the plug, so all the electronics are working. I believe the clutch itself is just a simple electromagnet, not much to go wrong there. Possibly a broken wire internally? Has anyone had this problem before where everything else is fine but the clutch just won't switch on?

edit: hrm, I just read my own post and realized I need to check continuity across the terminals of the airpump's plug. Will do that tonight.

Figured it out. Mods please delete.

i'd just get rid of it.....just a thought

Take the pulley off of one of the other ones that failed you and there you go. Or just get rid of it like tt7hvn suggested.

When you remove the airpump on a stock ECU, the throttle response at low RPMs is all kinds of messed up. As strange as it sounds, this is one emission control that's a "must-have" for track and autox use for me at this time.

Anyway, I fixed the problem and it runs like a top again.

could you kindly post the fix just for future reference.

What was the problem?

Sure, I'll recap. This is a relatively low mileage unit from a '95 I believe and doesn't exhibit any unusual bearing wear/noises, etc.

I noticed the airpump wasn't working properly while daily driving the car and noticed the idle was lumpier than usual and the car hesitated and bucked a little (almost like a badly adjusted TPS) at part throttle and at standing starts. Popped the hood and noticed the clutch was not engaging.

First thing I did was check the fuse. A/C shares the airpump fuse so I flipped the A/C on and it worked fine.

Next to check the relay, I disconnected the airpump plug and tested the voltage at the plug to see if it was getting switched on. +13.6V, it was good.

Then I checked continuity across the terminals of the airpump itself. The magnetic clutch is just a coil I'm pretty sure, so there's really not much there to fail if the mechanism itself is working properly (it spun freely, etc.). Got continuity and measured resistance across the coil.

So, according all my tests, everything is in good working shape, yet the clutch wouldn't engage. So a little further investigation of the wiring found the problem. Due to age/heat, the plug on the engine harness had become brittle and the wires going into the plug must have had an internal breakage in them because at certain angles (ie: when the pump was plugged in) there was no circuit, but at other angles (ie: when I was holding the plug up to test it with the multimeter) there was. This is why my tests showed everything was good yet it still didn't work. I cut the wiring out and soldered in new connectors on the engine harness and on the airpump. Everything works great now.

Glad you fixed it and thanks for the info :icon_tup: