Removed Air Pump, Dumping In Fuel On Start Up

[SVT_Z06]

2004 z06.

Removed the air pump. What tables do I adjust so I don't get that rich fuel smell on start up?

Thanks!

SVT_Z06

[WS6FirebirdTA00]

Post the log and tune.

Afterstart enrichment and OLFA normally handle that, but just removing the air pump should not make it rich, unless it was tuned accidentally with the air pump on, skewing the numbers during the cold starts.

[SVT_Z06]

Thanks for replying.

Yes, I tuned it prior to removing the air pump. From what I understand, the air pump pumps air into the manifolds on start up to help heat up the cats. Now I have no air, and a bunch of fuel on start up.

I haven't touched those tables you mention. I'll give it a shot and let you know if that did it.

Thanks again!

[Russ K]

I use the open loop table from a 2004 5.3 truck.

Russ Kemp

[Mike1995]

If its the same air pump configuration found on 4.3's, then the air pump is designed to introduce fresh air into the downstream of the exhaust manifold to mix in with the exhaust before the cat to lower emissions. This is what I gathered from AllData.

[93camaro_zzz]

If its the same air pump configuration found on 4.3's, then the air pump is designed to introduce fresh air into the downstream of the exhaust manifold to mix in with the exhaust before the cat to lower emissions. This is what I gathered from AllData.

This is what I understand it to do also. On some cars, it pumps air DIRECTLY in to the cat itself.

[jimmyblue]

AIR is meant to get the cat "lit off" from cold start
and without it, you will have a longer time in which
the HCs aren't burned. No way around that. You can
throw less fuel, cold, but that might not make the
motor idle as happy. Question is, is the stank to do
with excess fuel, insufficient fuel (both elevate HC),
fuel pushed out the exhaust and simply not cracked?