Threw 2 codes last night

[NORTY]

I have a 2006 Z06 with 43,000 miles. Threw codes PO171 & PO174. I looked them up and they appear to be "Left bank LEAN and right bank LEAN system 2."

My car was tuned about a year ago and I have a call into my tuner now. My engine temp is showing normal as all other guages are too. My nose tells me the car is "hot" when I get out of it.

Is the car safe to drive to the tuner (50 miles away?)

[LLC5]

It probably is ok to drive as long as your coolant and oil temps/pressures are good. It sounds like it could be a false air problem, check vacuum leaks and throttle body/air bridge clamps and hoses for tightness. Good luck with it.

[NORTY]

I DROVE IT TODAY ABOUT 100 MILES. i COULDN'T GET MY COOLANT TEMP OVER 200 BEFORE. TODAY, IT WAS @ 219F.
ALSO, (crap, caps lock!) the oil temp was about 195F instead of 165-170F.
The CEL went out. I'm baffled. Are the codes still stored even with the CEL dark?

[LLC5]

Originally Posted by NORTY

I DROVE IT TODAY ABOUT 100 MILES. i COULDN'T GET MY COOLANT TEMP OVER 200 BEFORE. TODAY, IT WAS @ 219F.
ALSO, (crap, caps lock!) the oil temp was about 195F instead of 165-170F.
The CEL went out. I'm baffled. Are the codes still stored even with the CEL dark?

Yes, they will be stored in the PCM until they are cleared.

[NORTY]

Car went to the tuner yesterday. He had his "super duper laptop" connected while driving for about a half hour. The car didn't throw any codes, but he said,"It would be perfect, then go lean, then revert back to perfect". We started looking for an air leak when he got back. Found none. He put it on the dyno (dynamincs) and did a pull. The car seemed kinda "lazy" at the absolute top of the rpm band. He said he was picking up slight detonation. We decided to try a colder plug (NGK TR6.) to see if that would run a little cooler and reduce detonation. (Damn 91 oct. gasoline!) He made another pull and the colder plugs seemed to be effective. He said I would have to change them out every 15,000 miles as they are the OLD style plugs, but oh well. At least the plugs are easy to get to!
It hasn't thrown a code since he cleared the PCM. Holding my fingers crossed as I have a trackday next Wednesday!

On a sidenote: He has a 2008 Z06 and tracks his modded car. He uses Hoosier tires with a 315 ON THE FRONT with a 18" X 11" wheel. You should see the backs...

[rocket8189]

For what its worth, my 04 C5 Z06 threw the same codes because of a leak behind the MAF sensor on a Halltech Venom cold air aftermarket intake; the coupler was a little tired. The reason for the lean codes is the MAF sends a signal to the ECM telling it how much air it measured inbound and calls for the proper fuel shot based on that air measurement. But because its pulling air behind the MAF, the air arrives at the cylinder with not enough fuel as called for, thus lean mixture.

Not recommending this, using a tuner, your car has probably been modified, but I went back to stock because my engine is not modified at all so, am I quoting C4C5, my Z06, like others, "was engineered to pull enough air with stock air intake (no headers or supercharger)." 700 miles ago, no codes and pulls as strong as ever. Again, not suggesting reverting to stock but I'm betting there is a leak in the intake behind the MAF sensor especailly is you have aftermarket intake. FWIW. Good luck

Love these cars.

Ken

[NORTY]

Thanks for the insight, but my car is 100% stock (except for the "tune.") Stock intake/exhaust cam/heads.

[c4c5specialist]

HI there,

The TUNE may or may NOT cause the issue.

Truth is, even GM had an issue with the front air being funneled into the air cleaner creating lean MAF sensor issues. Excess oil from being always at the full mark can create this condition as it may loosen the hydrocarbon patch that is on the inside of the air cleaner lid.

#1, put the GM plugs back in it. The electrode protrusion effectively reduces total ignition timing because its a different distance from the 41.110 ACdelco spark plugs.

#2, look at the MAF frequency as I will put bets the readings are either skewed or actually HIGHER than necessary. This will induce higher fuel trims and engine detonation.

Lets be clear, the details are the key on this but putting aftermarket plugs to MASK what is actually happening is not the correct course of action.

Allthebest, c4c5