I have 2014 with ecs.Had the car tuned a few weeks ago and car is running rich took it back to tuner today. He said my 02's are moving very little slow and something is wrong with them.They should be jumping all over, I just replaced them before i went thinking that was the rich condition. He took out some fuel so numbers are closer but after plugging scanner in looks like 02s21 is moving fast 02s12 is moving very slow. Is these the closes to the engine? right side?Left side?

 

I am thinking 02s11 & 02s21 must be the up stream they are jumping around.
02s12 & 02s22 are the rear ? They just move a little bit is that right? thanks

 

What mods do you have on the car?


Elmer

 

ECS with meth.stock exhaust

 

A properly working front 02 must oscillate rapidly between .100 and .950 millivolts However if you installed LT headers because the front 02 locations have been moved aft as much as 2-3 ft they end up not reading correctly and not heating up correctly---This in turn causes your engine at P/T to run very rich-This is why LT headers are illegal in most states---Now with tuning you can get the 02's to work better but they will never ever work the same as with stock headers---Lowering the 02 switching points helps somewhat ALSO many people will install the rear 02's onto the front locations as the rears tend to be more sensitive and read better---- With LT's be prepared to change the front 02's just as you do spark plugs as they get fouled and once fouled they will read wrong---
The use of a wideband is the only true way to see exactly what your AFR's are at P/T It should be 14.68-1 ( LT's can make your P/T fueling as rich as 12.1---) Even at WOT you need to do wideband tuning to see exactly where your fueling is At WOT it should be betwwen 12.4-12.9 AFR for best HP and TQ--Without wideband tuning LT's may produce very little or no HP gains as gthe fueling becomes rich----Claims of t30 HP gains with LT's is true--but only after a wideband tune and fueling corrections

PS These direct injected engines like a leaner WOT fueling----as high as 13.0-1

 

Great information.

 

I have been reading your post and I think that without me reading everything in the forum you can help me. I'm an above average mechanic for the older pre computer car's and recently bought a beautiful automatic C5 convertible from the original owner that is unmolested with the exception of a dual cold air intake and high flow exhaust of which I don't know the brand as the guy who I bought it from couldn't remember! The car runs really runs strong and pulls up to the triple digits without skipping a beat. My questions are what can I do (a hand held tuner maybe?) to get more power. It has 3.15 gears and I'm not really interested in putting headers on it. Just a personal choice. I know that ill get more power from them but if at all possible I would like to see if I can get by without them.
So any suggestions you have would be greatly appreciated. One other thing I might add is I have to do this on a budget!!!. I know that I'm asking a lot but I feel like you are the best person who has the answers I'm looking for after reading your post. Thanks in advance for your time and help with this.

 

If your car has a 3.15 rear gear it must be an auto trans These C5 cars are already well tuned bone stock However GM uses many programs in the stock tune that removes HP and TQ all the time---Simply deleting these programs that remove TQ will really wake up even a stock bolt on type car
1. A C5 has a drive by wire throttle--The stock program actually does NOT allow full throttle until you reach apprx 3400 RPM's so at launch the throttle is barely opened--Tuning will make the throttle act more like a cable throttle and will allow WOT when you floor it
2 The trans shifts are lazy on all auto trannies makeing them slip and costing ET's Tuning again will create crisp firm shifts with no slipping- this in turn lowers trans temps and wear--PLUS the firmer shifts gains ET's
3. GM commands fueling to be very rich in the low 11's AFR at WOT---However for best power it's best to lean the AFR's down some to ge some free HP
4 The stock timing tables have very little timing from off idle--Often less than "0" degrees and at "0" up to about 2000 RPM--adding timing in these low RPM ranges will really wake up the launch
5 On an auto trans there is a system called "TQ management" which at each shift will remove up to 30% of your TQ to "soften the shifts" This is a killer as at each shift your engine has to regain the momentun that the ECM has taken away and all that takes time--
These are the basics but there are several more programs in the stock tune that removes your engine's potential--
TUNING in simple words allows your engine to make the most HP and TQ it can all the time--without the ECM getting in the way