I bought an 07 z51 m6 last month just put the vararam intake w/ throttle body spacer, on it last week. I drove it about 20-30 miles felt nothing. Then yesturday I drove it another 80-90 miles and the check engine light comes on, but with the light the car felt like it came to life. I feel a nice diference from before I put the intake on, but I only felt the difference with the check engine light on??? has anyone had this problem? I've never heard of gettin a check engine light come on from a CAI?

 

Check to see if you have a leak at any of the connections.

 

Everything is tight. and like I said the car feels awesome now. When i first put the intake on didn't feel a difference but now with the light on it feels more powerful?

 

After my Vararam install on a 94 degree day i noticed a nice gain as soon as i got on the highway, but never got a CEL.

You wont notice much gain in city driving with the Vararam.

 

More than likely you have a sensor connection problem . The VR should work well from the get go. If you can get a scan tool you may see what the error code is. Otherwise i would disconnect & reconnect the
sensor plugs including the one on the Throttlebody. Also snug up the bolts on the TB

 

IT TAKES THE CAR 100 MILES OR SO TO "LEARN" the new intake and make adjustments.The CEL is either coincidence or something you forgot to reconnect,or a loose connection.Disconnect the battery for a few,then reconnect and see what happens.

 

Did you get gas anytime around then? if so, tighten your cap.

 

I never got that msg when I installed mine. But, if it runs great . . .

Give the guys at Vararam (Steve or Patrick) a call to get their thoughts, as well.

 

Same here.

 

I checked the throttle body bolts and all plugs, everything is tight and as it should be? I disconnected the batt last night and then started it up again no light. Then I let it idle a bit and reved it up, the light came back on. I'm doing my header install in a couple days, im doin dynatech system w/ cats and xpipe with borla sports then getting it tuned so whatever it is hopefully the tune will correct it. I just figured the mass airflow sensor was confused with all the extra air flowing through with a vararam set up thats waht caused the light?

 

I also descreened my massairflow sensor? but i've done that to all my c5's too with no prob.

 

You obviuosly didn't follow the installation instructions properly.

 

Tuning 101.

When you make any change to the engine front end (intake manifold, air cleaners, heads, ect) or the back end (exhaust, headers) the car runs leaner in closed loop. This is measured by the long term fuel trends in the PCM. When they are too positive from running too lean it trips a code for excessive lean. These cars come from the factory running 8-14 positive. Some add headers and make it 23 others add headers, aircleaner, and exhaust and get 23 which results in no CEL. Others add some of these mods and get to 25+ and get the light. The Long term fuel trends are not a steady number and it fluctuates up and down. All it takes is a few trips over +25% to trip the code. Barometric pressure, temperature and density (sea level?) affect the amount of air comming in. Some changes here and there and then it pops....the CEL. The car can only compensate for +24% lean before tripping a code for it. There is nothing wrong with any connections as that would trip a code for the sensor not working and since the only electrical connector in an air cleaner swap is the MAF, you would likely hit a reduced power mode if that happened.

When you change these parts on a car they must be tuned in. The car does not learn anything to adjust the fuel trends. It learns to adjust to them. That is a myth brought on because the car does learn to adjust airflow to keep a car from dying when airflow changes made by an owner arent addressed in a tune.

A car with positive long term fuel trends will be positive the day he puts on the part and will be the exact same amount positive a year later.

If you scan the car with HPtuners or equivalent, you will see that you have exceeded the car's ability to maintain stoic air fuel ratio and have long term fuel trends in excess of +24%.

By the way when a car reads that it is lean in closed loop, it dumps that percentage of fuel more in wide open throttle mode making the car pig rich giving a nice set of black tailpipes....more so than the guy that has a perfectly tuned car running at zero long term fuel trends.

Anyone in NY with this code that wants me to scan the car for free can come by my house and I will show it to you and if its a 2005 you get it fixed on the spot. Other years require the HPtuners license fee of 100 bucks that goes to HPtuners not me. Its free.

So tune the car and the light will go away for good.

Pat it forward....and I hope this helps.

 

Descreening the MAF required a change of the MAF table calibration in the C5 to the Z06 table which just had a larger scale increase cell to cell than on the screened MAF table. The C6 table is less sensitive but still warrants the adjustment. The MAF ultimately tells the PCM what clyinder airmass measured in grms/Cyl (by finding the Grms/sec vs. frequency from the maf table). When the airmass doesnt coincide with the predicted amount it manifests itself as a tip in throttle hesitation when you go from off throttle to on throttle slowly.

The screen although a small one is stil a restriction and removing it causes you to have to have a higher airmass prediction that if it was in place. As a result the Z06 maf in the C5 had higher airmass values as the table increases in frequency since more air gets through with the screen removed. I couldnt resolve the slight jolt I felt when I went from off throttle to on it when I removed the screen and it was Chris from East coast supercharging that informed me of this condition. When people come to me for tuning I adjust the MAF table with the same slope increase as I did in the C5.

Hope this helps.

 

So you think a good tune will clear the light?

 

[QUOTE=SpinMonster;1563380820]Tuning 101.

When you make any change to the engine front end (intake manifold, air cleaners, heads, ect) or the back end (exhaust, headers) the car runs leaner in closed loop.
By the way when a car reads that it is lean in closed loop, it dumps that percentage of fuel more in wide open throttle mode making the car pig rich giving a nice set of black tailpipes....more so than the guy that has a perfectly tuned car running at zero long term fuel trends.

Misinformation is the basis of confusion!

 

Absolutely. But I personally wouldn't drive around a lot with the car so mis-tuned that the car can't compensate and keep stoich. YRMV, but IMHO get it tuned and soon.

Spinmonster, not to hijack too much, but I've been complaining about a hesitation from throttle depression to the car revving up ever since I installed a ported throttle body. I still have my MAF screen in. I've got my LTFT's to -2 across the board and 0 at idle. The hesitation causes me trouble heel-n-toe downshifting as the car isn't as responsive as I like.

From your post it sounds like a MAF scale might be in order. I've kept the stock scale even with my cam, I just adjusted it at idle to get 0 ltft's at idle and adjusted be VE table to get the rest of the trims in order.

Would you mind emailing me your MAF tables so I can see the scaling?

 

why did u say misinformation? is spin monster incorrect?

 

Feel free to let us know what part of that is misinfo...

Always like to be corrected when I say something wrong. I take the time to help with what I have done to 100 cars and you help so much by saying its wrong with nothing to back it up. Big help to the members.

I love when old school mechanics come on here not knowing the first thing about the C6 or C5 platform nor have they scanned a single car to even know what I and the entire scan and tune section are even talking about.

 

Yes and if you drive to my house, not only will I scan the car with you there and show you everything I said to be true, I can tune out the issues. Im in Farmingdale about 30 miles from you.

You will see the Long temr fuel trends on the scan at +24 peakinghigher. At the end of the tune it will be as close to zero with out being positive. The car dumps fuel in proportion to the percent lean it reads on the LTFT's. Come see it for yourself then you can come back on here and tell everyone what we did and what it accomplished.