88 iroc and a 165 ecm

If i remove my smog equipment do i have to worry about codes being set.


Lastly does anyone have any instructions on removing the smog equipment. Some of it is already missing and the valve covers vent directly to the atmosphere now anyways.

DAve

 

I've asked similar questions before, specifically what effect does removing the AIR pump have on the fuel calibration? I would THINK that the extra O2 being injected into the exhaust would affect the O2 sensor's output, which the ECM would have to take into account during closed loop operation.

I've heard people say, however, that removing the pump doesn't seem to change the A/F mixture, so who knows. I can say that on my 86 TPI 305 camaro, removing the pump and plugging the holes didn't cause any apparent change in drivability nor did it set a code.

You mentioned the valve covers, so you might be asking about the PCV system. You might run into the same kind of problem, as the PCV valve is essentially a deliberate vacuum leak. Unlike the AIR system however, the PCV provides a useful function over-and-above smog control. By circulating air through the crankcase, you remove some fuel vapor that would eventually contaminate the oil. Also, it insures that a slight positive pressure is maintained on the outside of the motor, potentially reducing the possibility of gasket and seal leakage.

 

From what I understand, the air diverter valve only pumps air into the manifolds during closed-loop startup, and diverts the air to the cat most of the rest of the time.

 

I wonder what happens if the CAT does not get the air - probably less than complete burn of the excess gases going thru there? Hard to imagine that extra oxygen would be needed at those temps.

Dave

 

I know the AIR diverter feeds the cat sometimes which is downstream of the o2 sensor. I guess there are some additional pipes feeding into my headers. I think i want to block those off.

I have airfilters on top of my valve covers now instead of where the pcv used to be thus the gases are venting direct to the atmosphere. It passed emissions this way by a gm dealer.

Dave

 

The matrix starts to collapse, from the heat.
they need the extra O2 or the service life gets real short.

 

Can i run an air pipe from the smog pump direct to the cat. This way i get rid of the diverter plumbing on top of the motor and the cat still gets the air it needs for complete burning of excess gases.

What is the purpose of the smog pump feeding the intake manifold? or the headers when it is not feeding the cat - air tempature???

 

the hole deal is all about heat and how hot it all needs to be (to burn of left over fuel and gases) durin warm-up the diverter valve puts the air into the exe. manifolds to add O2 so that extra fuel is burnt off this also gives the exhaust a boost in temp to help get the cat up to it best operating temp after its all hot the diverter puts the air to the cat this added O2 does 2 things once again burns off left over fuel BUT more importantly it gives the extra oxygen atoms to change carbon MONoxide (mon = mono 1 oxide = oxygen) too carbon DIoxide (di=2)and that is the main goal of the cat

------------------
Ya sure it is just an RS

B4Cyaa

1991 RS B4C
Former Nebraska Highway Patrol Car
305 TPI
WC T-5
Four Wheel Disk Brakes
Only Options
Rear Defrost
Am-Fm Radio
Red-int White-exe
One BA Of A 350 In The Works
Mods
Dynomax Cat Back (to hold me over till I got the $$$ for the Borla)
best 1/4mile Run of 14.92@94.83
with 145,000 on her

https://www.thirdgen.org/rides/index.tgo?action=view&rideid=2201
god speed dale

 

Interesting.

I am going to be putting on a Mac catalytic converter and they said I could just weld the AIR tube shut if I wanted to.

How do the 4th gen 2-way cats differ from our 3-way cats internally?

I bought an AIR pump delete pulley and a 4th gen electric AIR pump with plans of removing the PEDES valve, but now I'm not so sure...

 

Cats that dont need air injection just run at a lower temp (and are less efficent) plus I think that there more restrictive to help them heat up not sure though
sorry about the cemistry lesson

jacob

------------------
Ya sure it is just an RS

B4Cyaa

1991 RS B4C
Former Nebraska Highway Patrol Car
305 TPI
WC T-5
Four Wheel Disk Brakes
Only Options
Rear Defrost
Am-Fm Radio
Red-int White-exe
One BA Of A 350 In The Works
Mods
Dynomax Cat Back (to hold me over till I got the $$$ for the Borla)
best 1/4mile Run of 14.92@94.83
with 145,000 on her

https://www.thirdgen.org/rides/index.tgo?action=view&rideid=2201
god speed dale

 

Did they say it would last as long with it welded shut?
4ths use a 2 way cat?, where'd you hear that?

The 4ths have a much better calibration, and the newer ones with the OBDII stuff are really good. That's why they can get away with a part time air pump.

 

Where did you get that info.?

 

Dont hold me to that Grumpy I just remeber mabey reading that somewhere (I could also just be pulling this out of my A$$ but I dont remember where I read it) like I said I might be just full of it I dont know but anyway modern cats are like 3 in one right My 78 monte carlo HAD a big old cat with no air so they dont all need AIR to work I know that

soo if im just sounding like an idiot(LIKE ALLWAYZ ) straighten me out ok
later
jacob

------------------
Ya sure it is just an RS

B4Cyaa

1991 RS B4C
Former Nebraska Highway Patrol Car
305 TPI
WC T-5
Four Wheel Disk Brakes
Only Options
Rear Defrost
Am-Fm Radio
Red-int White-exe
One BA Of A 350 In The Works
Mods
Dynomax Cat Back (to hold me over till I got the $$$ for the Borla)
best 1/4mile Run of 14.92@94.83
with 145,000 on her

https://www.thirdgen.org/rides/index...ew&rideid=2201
god speed dale

[This message has been edited by 91B4C jacob (edited June 14, 2001).]

 

I just put a bassani x-pipe on my friends 97 mustang gt and the cats were tiny and had no air. I want to know where to get cat's that small.. plus they had no air at all, and neither did the stock i believe. I think a lot of cats don't need air fittings. If I ever replace my cats, I am going to try to get non-air ones, so I can remove my air pump.

 

Ok, since there's no AIR tube on the 4th gen cats I *** -u-me'd that they were only 2-way. My bad. Mac did not speak to the longevity of the cat without AIR injection. That was my bad again for not asking.

So what you're saying is that not injecting AIR into the catalytic converter body I will drastically shorten the life of my new cat?