Air Pump Delete / Idle Issue

orange9mm · 01-24-2009, 02:06 PM

I finally got around to replacing my belt driven cooling fan with a electric one. I had updated my alternator to a delco remy a few months back for this purpose. I was originally going to keep the air pump but after reading some older posts about it I decided to remove it instead. I plugged the air pump hose leading up to the top of the motor from the pump. Now my car is idling about 500 RPMs higher. Is there any reason why deleting the air pump would cause my car to idle higher? Did I not do the delete correctly. Should I remove more air pump plumbing?

Electric fan

Hose I plugged

No Air Pump, you can see the plugged hose above the air pump bracket

Danglerb · 01-24-2009, 06:46 PM

I imagine the fan and air pump put some load on the engine, so removed idle would increase, but 500 rpm seems too much. Check for vacuum leaks, or something else disturbed in the install.

Fan doesn't look very big, hope it pumps enough air in the summer. How many amps does it draw in steady running?

orange9mm · 01-24-2009, 08:01 PM

The fan is 18" and is supposed to flow 2100+ CFMs. The draw is 14.4 AMPs. I got a deal on it and I wanted something similar in size to the factory clutch fan so I could keep the existing fan shroud. The picture makes it look small but the fan shroud is 20" in diameter and you can see fan has about a 1" on either side. So far it is cooling the car fine. I have not driven the car really hard since installed though. My car has always held at about the 1/3 mark while driving and when in heavy traffic or stopped it would rise above 1/2 and I have seen it hit around 3/4 a few times. Now it never goes above the 1/2 mark. A side benefit is noise, my car is quieter now. But now it idles fast so it is louder in that respect. I will check around for a possible disturbed vacuum line. I am glad to have it confirmed that the delete should not effect my idle.

N2O-SHARK · 01-24-2009, 08:03 PM

Did you plug the vacuum line that went to the diverter valve? If you forgot it would let you idle high.

MPDano · MPDano's Garage

Lucky you guys. Does Texas have smog laws?

Danglerb · 01-25-2009, 12:18 AM

A good radiator makes up for a lot, but the blades are kinda small, and flat, not curved, plus 14 amps is a tiny motor for a radiator fan. Can't argue if it works for you, but that first hot day with AC may be an eye and or window opener.

orange9mm · 01-25-2009, 12:27 PM

Ah ha. I didn't plug the vacuum line running to the diverter valve thanks for the tip...

Texas does not test for emissions, at least not in my area. They do have laws preventing/tampering with the original emission equipment on the vehicle unless you are updating to something that was used on a later model. I have yet to have a state inspection where they would even look under the hood. I will say that if they see a cat sticker on the vehicle then they will expect one.

With my AC on I will have 2 fans running, the pusher fan in the front and the puller fan behind the radiator. If this fan proves inadequate I will get a higher flowing fan. If is only happens during AC operation than I will consider updating the pusher in front. It does not start getting hot here until sometime after March. August is really hot here so that will be the month to beat...

orange9mm · 01-25-2009, 01:22 PM

plugging the vacuum line on the diverter valve worked, no more fast idle. thanks N2O-SHARK

N2O-SHARK · 01-25-2009, 03:34 PM

Figured that was what happened. Did the same myself when I pulled my smog junk off.