I want to remove the smog pump according to the tech article.
One thing makes me hesitate though. Wont this affect the air/fuel mix since the oxygensensor is situated after the exhaust manifold? If I figure it right this would initially( when the pump previosly fed air to the manifold) give to much air at the carb?
Please tell me that Im wrong or that it doesnt matter since I really want to get rid of the smoggarbage.

Hasse
Sweden

 

The smog pump just feeds air to the CATS. The air is suppose to burn the rest of the gases inside the CATS to make it emissions legal. That's why if you have good working CAT or CATS you do not want to get rid of the pump. If you do you're looking for them to clog up. Most people do this after they gut the CATS out because the pump is not serving a purpose anymore (just blowing air into a hollow exhaust pipe).

It shouldn't effect the O2 sensor. You just cap off the AIR tubes coming out of your headers or exhaust manifolds, then all the exhaust has to go through the manifolds and out the exhaust pipes.

 

I was told by someone that the smogpump pumps air into the exhaust manifold until the engine has heated up, and then into the cat. Is this then incorrect?

 

Thats exactly how it works.

 

¨Then if this is how it works, the oxygensensor should get a richer reading resulting in fooling the ECM to make the air/fuel less rich?

 

The air pump doesnt affect the o2 at all. When the car is cold the air is pumped into the manifolds. That does change the o2 readings but it doesnt matter because the car is in open loop and the ecm is ignoring the o2. When the car goes into closed loop the air is swithed to the cat. Since that is after the o2 the o2 readings arent affected.

 

Ok thanks for this great information. Ill get rid of the cat and the smogpump.

 

According to the 8D code found in 90-92 TPi cars ECM changes the O2 readings by 100mV when AIR is diverted.....

/N.

 

Will that 100mv difference be a big effect? I know I couldn't tell any difference after capping off the AIR tubes.

 

The BLM values will "probably" be affected by it when AIR is diverted, but I dont think you will notice it unless you hook up a scan tool and suddenly sees the integrator change+BLM......

/N.

 

im glad you guys are talking about this............i read the tech article and did a search but what exactly do i ned to do to remove that smog pump and the air system??????????????

 

If serpentine, which yours should be, use a breaker bar to take the belt off, take the torx bolts off the smog pump pull it out, put a new shorter sepertine belt on (might check around at auto places) I know I couldn't get the exact size listed in tech article so when I went to the next closest it was like 29 bucks! I went to a 1/4" one way forget which and it was 10 bucks cheaper go figure. After that you need to go to a hardware store buy some pipe ends (little screw on caps) cap off the AIR tubes coming from the headers or manifolds and cap off your lines coming back up from your CAT(S) I just capped them off under the hood cause I was to lazy to remove the lines and plug them. Undo your wiring for the smog pump and that's pretty much it. I might have left something out, so you should still read the tech article I wrote this whole thing in about a minute.

 

lol. thanks tho its some great info!!!!

 

But does the CC carb code include that as well? MAF TPI? TBI?