KC Allen

So I just bought this 2006 Chevy Cobalt SS 2.0l Lsj and I have been driving it everyday for 3 weeks no problems. Car only has 90k miles on it. 2 days ago I jumped in my car and turned it on and the cel turned on and it idled weird for a second then went back to normal. I started driving it and the car drives and runs like a brand new car but the Cel is still on?? lol. That night I pulled it into my garage and started to check the whole car out because I am the third owner and I found that the car has a full catless Magan racing exhaust system from the header to the tail, and when I pulled the headlight off to see what was going on with the intake I found a complete K&N CAI system attached. So I immediately pulled the MAF and hosed it down with MAF cleaner let it dry and reinstall. Put everything back together and went to my mechanic guy to have the codes cleared. 2 cycles later the Cel comes back on. The next day I went to Autozone to actually see what codes it was throwing, and it was throwing a P0171 lean code to Bank 1 and the readout also stated that this is normally vacuum line leaks but could be numerous things, and when I say numerous I mean I have never seen one code hold so many different possible issues. So I immediately started searching for vacuum or boost leaks. Found none! Normally I am pretty savvy at finding a problem on a car quick and fixing it, but this is where I finally tap out, the car runs like a brand new car, I dont really get it. PS the Megan racing catless pipe is gone and leaking out the bottom, causing the car to be pretty loud, but if it was that causing the Cel to come on that would of happened weeks ago on the second cycle like they are designed to do. So I know its not the exhaust. Any help will be much appreciated, just got this car and sure enough the cel flips on 2 weeks later. smh

exninja

iTrader: (1)

What are your fuel trims? It could be that your ECU is compensating and that's why it's running ok, but the trims could be way off. What did you do to look for vac or intake leaks?

double clutch

iTrader: (1)

Do you know if it is tuned for the intake?

KC Allen

I didnt think the car came with a fuel ratio gauge, and I know it doesnt have a vacuum leak because of the vaccum gauge and no hissing. Im not spraying carb/starter fluid all over this beautiful engine and car to check that when the vaccuum gauge reads perfect with no hissing. The car only has 90k on it, and garage kept, all the hoses look brand new still from factory. Any help would be appreciate, thanks bud.

KC Allen

Im not sure, but if it needed tuned it would have thrown that code weeks ago on the second cycle like they are designed to do. Any more ideas and help would be appreciated. I read on the internet that the 2006 Chexy Cobalts had a recall calibration for the MAF and has to be sent in to get a TBS maf calibrated on it for an update.

exninja

iTrader: (1)

Any OBD reader will be able to read the STFT and LTFT. You don't need a wideband for that either, those are basic fuel injection functions (NA or FI regardless).

When you say vacuum gauge, do you mean the boost meter on you a-pillar? That's not going to tell you if you have a vac leak. The pressure difference due to a vac leak is very slight and you won't see it on the gauge.

There are multiple ways to test for vac leaks, carb cleaner is just easy and doesn't require separate equipment. And I wouldn't be concerned about spraying it, it's not going to do anything to the car.

I'd at least find an obd-ii scanner and see what's going on with the fuel trims. A look at the tune is also good, if possible. If the MAF location or dimensions changed without accounting for it then lean codes are going to happen.

KC Allen

Where do I find a OBD scanner and what will I learn in the trims to fix the car? It cant be the tune because it would have thrown that code weeks ago on the second cycle but it didnt.

KC Allen

Will this read my fuel trim if I put it on my car?

https://www.modernperformance.com/pr...ii-scan-gauges

Sharkey

iTrader: (1)

yes it will. that gauge is the single best thing you will ever buy for your cobalt ss.

exninja

iTrader: (1)

you can also just get a cheap scanner on amazon that will do it. you will learn when the issue is occurring (idle vs. cruise vs. WOT etc), or if it's even happening. you'll learn if it's constant or erratic. from there you can figure out how bad it is, if it's tune-related or not, o2 sensor, leak, etc. etc.

umrdyldo

iTrader: (1)

https://goo.gl/PK1HLq

Order one of these bluetooth readers if you have an Android phone get the Torque Pro app. You can then add LTFT and STFT to the app and monitor it that way.