# Bypassing air pump **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** mercedes-benz, e-class\ **Created:** [February 11, 2010, 2:21am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261 "2010-02-11T02:21:29Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 2:21am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/1 "2010-02-11T02:21:29Z")
I went to start this heirloom, daily driven, Benz, heard belt noise and observed smoke coming from under the hood. I opened the hood and noticed the air pump pulley was frozen, the smoke was the belt being friction fried!! My mechanic informed me I could belt bypass the air pump, and the air conditioner compressor, which I agreed to as a quick fix. He also informed me that in MA a 1990 car is exempt from emissions testing and bypassing the air pump the car would surely fail that test. Here’s my question since the check engine light is now occasionally on. Is any damage being done by driving the car without an air pump, are the sensors and computer able to handle what is now shitty emissions? ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [February 11, 2010, 2:29am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/2 "2010-02-11T02:29:26Z")
The only damage that’s being done is to our atmosphere. But even with the pump working, the difference is insignificant. Drive on… ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 2:51am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/3 "2010-02-11T02:51:03Z")
Thanks for the feedback, a plus was increased MPG by not running the pump and AC compressor ---
**Author:** ![oldschool](https://avatars.discourse-cdn.com/v4/letter/o/e19adc/32.png) [@oldschool](https://community.cartalk.com/u/oldschool)\ **Post date:** [February 11, 2010, 5:11am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/4 "2010-02-11T05:11:15Z")
If your secondary air injection pump is needed to get your vehicle into “closed loop” operation, you do indeed have a driveability problem and your problem is greater than increased pollution for the rest of us. I am not in favor of disabling any emission system, you may be shortening the life of your catalytic converter by operating your vehicle as so described. ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 12:31pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/5 "2010-02-11T12:31:17Z")
Thanks for the feedback, ---
**Author:** ![Loafer](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/loafer/32/28_2.png) [@Loafer](https://community.cartalk.com/u/Loafer)\ **Post date:** [February 11, 2010, 12:46pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/6 "2010-02-11T12:46:46Z")
You can removed the pump. I’ve done it on numerous vehicles. ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 1:06pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/7 "2010-02-11T13:06:29Z")
Thanks for the feedback. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [February 11, 2010, 1:06pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/8 "2010-02-11T13:06:56Z")
In addition to potential issues described above, permanently disabling the air pump and AC is a step to ‘heapdom’, where you figure out reasons not to keep you car in good shape. Temporary? OK. Permanent? Not what I’d do to my car, ‘heirloom’ or not. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [February 11, 2010, 3:27pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/9 "2010-02-11T15:27:41Z")
The secondary air pumps purpose is to inject air into the exhaust stream to light off the catalytic converter(s). Without the air pump the catalytic converter(s) will eventually plug up and will have to be removed or replaced. Tester ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 4:09pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/10 "2010-02-11T16:09:35Z")
Thanks for the feedback, yes temporary ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 4:11pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/11 "2010-02-11T16:11:02Z")
Thanks for the feedback. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [February 11, 2010, 4:26pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/12 "2010-02-11T16:26:43Z")
Since the car is exempt from emissions testing, you might as well “De-Smog” the whole thing (I.E. remove the converter) but since an oxygen sensor is still controlling the fuel mixture, converter plugging might not be an issue… Or you could be a good boy and remove the pump and soak it in a bucket of kerosene with a quart of ATF mixed in and see if you can free up the internally rusted air-pump. They are a simple, durable, cast iron vane pump. The vanes can stick (rust) to the pump housing. Sometimes you can break them loose and you are back in business. The pump has virtually no drag on the engine so fuel mileage is not an issue. As Tester said, the pumps purpose is to supply some oxygen to the exhaust stream so the converter has something to work with. Today’s more sophisticated systems no longer need this added oxygen, or it is introduced without the need for a pump… ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [February 11, 2010, 4:31pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/13 "2010-02-11T16:31:13Z")
Noooo - I strongly recommend against desmogging. By 1990 these cars were well designed to work well with the smog equipment. Just the wrong thing to do. ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 11, 2010, 7:45pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/14 "2010-02-11T19:45:54Z")
I really appreciate all of the feedback. The car has only OEM replacement parts as it will be with the air pump. So can the car be driven daily for another month or so set up this way? I’m not feeling there is a sense of urgency, the feedback is mixed. ---
**Author:** ![Skypilot](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/skypilot/32/237_2.png) [@Skypilot](https://community.cartalk.com/u/Skypilot)\ **Post date:** [February 12, 2010, 12:51am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/15 "2010-02-12T00:51:38Z")
I would think that after driving the car for a month or two you will be running a chance of destroying one of your catalytic converters if it has more then one. It will be your gamble! You might check on the cost of a catalytic converter before you decide to run your car for a month or two. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [February 12, 2010, 1:07am UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/16 "2010-02-12T01:07:51Z")
The smog pump will be heart-stopping expensive, as are most Benz parts…So it’s worth a try to free it up. These things are NOT built like a Swiss watch, they are pretty crude and can survive a little neglect… ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 12, 2010, 3:52pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/17 "2010-02-12T15:52:14Z")
Thanks for the feedback. I’ll try soaking it this weekend. ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 12, 2010, 3:52pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/18 "2010-02-12T15:52:58Z")
Thanks for the feedback. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [February 12, 2010, 3:54pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/19 "2010-02-12T15:54:17Z")
You also might try Ebay and auto recyclers for a used one. ---
**Author:** ![1990\_300E\_2.6](https://avatars.discourse-cdn.com/v4/letter/1/3e96dc/32.png) [@1990\_300E\_2.6](https://community.cartalk.com/u/1990_300E_2.6)\ **Post date:** [February 12, 2010, 6:12pm UTC](https://community.cartalk.com/t/bypassing-air-pump/44261/20 "2010-02-12T18:12:10Z")
Thanks for the feed back.