i have an 02 SS, and since i bought it i have had seriously poor mileage and i have since then swapped spark plugs, had the dealership replace one Cat and o2's on one side since they were throwing codes. But this hasn't fixed the problem i don't feel the car miss firing at all but i believe that she is running extremely rich. i have seen some post's on LS1 tech about the AIR pump removal on the 02 and i believe the 98-00's have EGR... but correct me if im wrong there. would this mod be a possible fix for the car running rich? i have made sure my K&N air filter is clean, and the only other thing i would like to check is my fuel filter is clean...the thing that is throwing me for a curve is the car only has 36k miles on it currently, any advice?

 

i'm wondering if the check valves on the AIR system are bad and causing a leak. and i understand that this could lead to a Rich A/F ratio. the AIR system is only needed to get the Cat's to work on cold start situations and then shuts off. if Craby or anyone else has any tips i'd appreciate it.

 

No EGR in '01-'02 SS...

Which specific code #s do you have currently?

Many folks remove the AIR system when adding LTs and ORY. Be sure to try a few tanks of a good fuel system cleaner monthly (I use Lucas), if you don't already do so.

 

i have tried many different types of fuel system clean i usually use STP, tried Lucas as well as SeaFoam. i have no codes popping up but when i bought the car it had a bad cat and what that low mileage i can only imagine what may be wrong. i would assume the AIR system is possibly giving my o2's a false reading of some kind and throwing unnecessary fuel into the engine.

 

It would confuse the O2s if excessive air got into the exhaust ahead of the upstream O2 sensors. The extra air would make the O2 sensors falsely see a lean condition and the PCM will tell the injectors to richen the fuel mixture.
However, the check valves are there to prevent the exhaust from frowing back into the AIR system and cook the hoses and the AIR pump, and even it they were stuck open the leaking exhaust would not affect what the O2 sensors are seeing.

The downstream O2 sensors only complain when the filtering ability of the cat failed, but have nothing to say if the cat is clogged. Being that you had to replace one cat, the other cat is probably bad and choking one side of the engine.

 

i have a hypertech programmer and it doesn't read any DTC's. i found this on LS1tech forums about the AIR system creating a extreme rich situation as well as exhaust back fires in some cases. unfortunately i really don't have a good enough scan tool to give me air/fuel ratio's and don't want to put in a wideband 02 and gauge yet for that. i'm assuming here that the AIR pump is probably not shutting of like it's supposed to and pushing air through the exhaust all the time and thus causing my problem. if my check valves were in good condition theoretically i could just pull the fuse for the AIR system correct instead of totally removing all the hoses and blocking off the manifolds etc? i've honestly been too busy with work (installing car electronics) for other people and school to play with my own car too much.

 

well i began my trial looked through my Haynes wiring diagram for the Air pump fuse and it doesn't look directly linked to any other circuits. i topped off my tank and will try to give updates as things develop i have already gotten the SES light on my gauges, so the computer does recognize that the system isn't working.

 

well my test is going well thus far on past full tanks i have only gotten approx 160 ish miles to the tank from full down to about an 1/8th. after pulling my AIR system fuse on my first quarter of a tank of gas i've gotten 98 miles this tank seems to be acting like it's gonna last. driving routes haven't changed, neither have my habits and i am still getting my gas from the same place. i'll post again once i've ran through the entire tank and see if this was the problem.

 

well good results after two tanks of gas (premium 93) i have averaged 18.9-22 between city and highway a large improvement from the 13-15 i had been getting and all from pulling my AIR fuse. i have gotten three DTC's on my ECM all for the AIR system Po410,Po412,Po418 if i remember correctly. and im now gonna look to either getting some headers without the AIR hookups and having those codes wiped or just blocking off the factory manifolds and still wiping the codes.

 

Try this:

http://www.ls1tech.com/forums/genera...much-fuel.html

Thats my write up when I was having a VERY similar problem with my 01 LS1 motor