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2005 Platinum CTS V-Headers+3in pipes
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Discussion Starter #1
So i have averaging 13mpg mix per tank and at cruising speeds,in gear,(60-70mph) never getting above 20mpg on the instantaneous mpg. I called Jesse @ W4me for a tune earlier and mentioned that i was running rich close to the 10s and he said my mass air flow must be dirty but i had cleaned it with radioshack electronic contact cleaner when i installed my intake so i figure it's clean..

maybe im just over reacting, is it really running too rich? the tech dynoing the car thought i had an aftermarket tune..:hmm:


Did i clean the MAF with the wrong cleaner? i didn't think it made a difference maybe i should do it again?
 

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'06 Z06, '05 CTS-V 453rwhp/434rwtq (sold)
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You are rich. stock tune?

Your car would be happier at about 12.7 above 4000 rpms.

You're at about 11
 

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04 CTS-V, 05 STS, 07 SRX- All sold :(
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02 sensor maybe? If it's reading a false lean condition, it'll cause the PCM to dump fuel in an effort to correct it. Since it was never really lean in the first place, you end up rich. That would explain the rich cruise anyway, but not on the dyno (the car ignores the 02 sensor under WOT).

Maybe you're getting an incomplete burn due to tired plugs and wires?
 

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Welcome to my world. I'm in the same boat. A/F peaks around 11.7-9 and it should be 12.7. This is why I'm trying to buy software so I can get in there and see what's going on.

My MAF was clean, and I recently upgraded to the NGK TR55's which Jes recommended. Not sure if that fixed my problem without another dyno run.....or software.
 

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seems odd that the ecu would force the tun to go back to a worse setting then what the tunner set. i know that happens with the ecotec motors but a v as well?
 

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2005 Platinum CTS V-Headers+3in pipes
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Discussion Starter #8
02 sensor maybe? If it's reading a false lean condition, it'll cause the PCM to dump fuel in an effort to correct it. Since it was never really lean in the first place, you end up rich. That would explain the rich cruise anyway, but not on the dyno (the car ignores the 02 sensor under WOT).

Maybe you're getting an incomplete burn due to tired plugs and wires?
if the O2 sensor was fouled up wouldn't i be throwing codes like crazy? the car only has about 23k, i didn't think the plugs and wires could be a factor considering the mileage..

You are rich. stock tune?

Your car would be happier at about 12.7 above 4000 rpms.

You're at about 11
yeah stock tune with Lingenfelter CAI and 3.5 Al intake tube.. i thought that a CAI intake would make it run lean :hmm:



will, has your MPG gone back down like BacDoc or has it remained steady?
 

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my mpg on my trip to work this morning was around 20mpg. and my commute is alot of sitting in traffic on rt 17 then the parkway.
 

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Actually my mpg is better than 20mpg. I'm getting nearly 24mpg highway. 17 around town.


I'm wondering if it's just a dyno thing showing the rich condition or something.
 

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There are two fuel ratio curves: What is shown on most dyno runs is a wide-open-throttle "WOT") fuel ratio, which in most cars is an "open loop" condition. GM has always run rich at WOT, and tuners gain some real horsepower by leaning out the WOT condition.

Normal cruise and light throttle action fuel ratio is ALWAYS closed loop and ALWAYS at 14.5:1. Any material change in this ratio will pop some codes indicating bad oxy sensor or inoperative cat. You can verify your cruise fuel ratio by an air-fuel meter. Innovate sells them for about $350, as I recall.
 

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See you in the funny papers
04 CTS-V, 05 STS, 07 SRX- All sold :(
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if the O2 sensor was fouled up wouldn't i be throwing codes like crazy? the car only has about 23k, i didn't think the plugs and wires could be a factor considering the mileage..
Not necessarily- I've seen plugs and wires ruined in that amount of time, especially if you're running rich.

yeah stock tune with Lingenfelter CAI and 3.5 Al intake tube.. i thought that a CAI intake would make it run lean :hmm:
Ah ha- might be that Lingenfelter and tube. I know everyone loves hot air intakes and tubes, but I've seen them introduce a lot of turbulence across the MAF, which creates false readings and throws your fuel mix out of whack. Some cars like them, while other cars don't. Mine was one that didn't, and I even made a thread about it here:

http://www.cadillacforums.com/forum...9-take-off-your-performance-intake-youll.html
 

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Discussion Starter #13
wow 20 -24 MPG in a :v:.. I guess i just need a tune :crying2:
 

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Actually my mpg is better than 20mpg. I'm getting nearly 24mpg highway. 17 around town.


I'm wondering if it's just a dyno thing showing the rich condition or something.
well thats my crappy morning commute. when i went to ac last weekend i got in the upper 20's on the highway. i do get 17+ around town.
 

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Discussion Starter #16
Not necessarily- I've seen plugs and wires ruined in that amount of time, especially if you're running rich.



Ah ha- might be that Lingenfelter and tube. I know everyone loves hot air intakes and tubes, but I've seen them introduce a lot of turbulence across the MAF, which creates false readings and throws your fuel mix out of whack. Some cars like them, while other cars don't. Mine was one that didn't, and I even made a thread about it here:

http://www.cadillacforums.com/forum...9-take-off-your-performance-intake-youll.html
thanks tony i guess i will see what W4Me can do for me
:banghead: mod hell:lildevil:
 

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I've talked to Jes about it already. But I can't tell if the richness is fixed without putting it on dyno ($$$) to get my A/F raito. That's why I'm looking into software or at least a gauge.
 

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05 maggied CTS-V, 2017 NSX Whoo Hoo!
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My mileage is for crap, but I was told that was gonna happen (get worse) when I had the burble and pop on decel turned off.

I was gonna get a license plate frame that says:

KISS ANOTHER DINOSAUR GOODBYE

I want to get the most bang for the buck from that stupid "gas guzzler" tax they nailed me with.
 
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