Hello all,

New to the site. I am receiving codes P0172 and P0175. I know they are both for fuel rich condition. These codes showed up after I had Magna Flow exhaust and x pipe installed also installed dual cone cold air intake. Could these mods be causing the codes to be tripped and if so how can I eliminate this problem.

 

If those are the only changes, look for an air leak. An unmetered air leak (after the MAF) can cause this condition. Check the EVAP lines on the driver's side, make sure they are correctly installed and not leaking also. The EVAP has an electrical connector and a green (mine's green) cap where a Schrader valve is connected to the EVAP line. The line itself is bent like a snake.

 

Hi,
I am going thru the identical problem. I just installed a smooth throttle body from Eckelers and started getting the PO172 and PO175 rich on bank 1 & 2. Went to Autozone for a further look at the problem, cause they do a code read for free. They give you the same DTC that the car's computer gives us but then they go onto their computer system and gave me a printout of potential fixes.

1) If bank one and two codes set together suspect fuel pressure or MAF (Mass Air Flow) sensor.
2)Oxygen sensor defective
3) Ignition misfire-repair
4)Fuel injector problem

I suspect that since I played with the air ratio and didn't play with the fuel mixture is why I got the same DTC codes as you. Now my check engine light is on and will not go off. I also found info from the forum as a few guys gave me the following. Check for blockage in the air way, the MAF, etc. even double check the air filter to make sure nothing is blocked up. Also I know it may be stupid but check that the MAF arrow on the unit is pointing towards the engine. I hope this helps a little. I am checking the stuff above myself and then going to change the Granatelli MAF that was installed a long time ago back to the original to see if that stops the two codes. I did get these codes after installing the MAF but never the check engine light . Obviously when we play with the air intake the car needs to be retuned. Something I failed to find out until now. Oh well I hope you make out alright and get to the bottom of your problem.

 

The computer can make adjustments to the fuel trims on it's own and learn them out--However the maximum before throwing a code for a rich or lean condition is normally +25% and -25%---That is a huge error in fueling that points to a problem rather than trim adjustments due to new performance parts---I would look at the MAF--typically too much oil on the filters will cause the MAF to read erroneously--or a hose that was left disconnected or one that is broken----Also look for exhaust leaks

 

You are running the same MAF, correct? It wasn't mentioned in the original post but after market MAF's can cause this.

 

yes I have not changed the MAF. Never removed or touched anything from MAF back. Exhaust was done by prof. installer air intake by me.

 

Take the Granatelli MAF off and put your stocker back on. See if that makes a difference.

Also (taken from Gearchatter)--
Excessive fuel in the oil will cause DTCs P0172 and P0175 to set at the same time. Remove the PCV valve from the intake manifold and plug with a suitable stopper. Also disconnect the fresh air pipe from the rocker cover and plug with a suitable stopper.
If the long term and short term fuel trim values increase, indicates
there is fuel in the oil.

 

I did just this on my 97 which had the Granatelli MAF and the smooth thottle body. I was getting the PO172 and the PO175 and then had a Check engine light on constantly. This all started right after the new MAF and the smooth thottle body. I just got through putting back all the old stock air system, except I left the Air Hog air filter in instead of the stock one and the codes cleared and the check engine light went off and has not come back on. I believe for me I need to head off to a tune shop and when I put the after market air stuff back on have someone retune the car to match the new air flow.

 

Not sure where you guys are going, original poster is running his stock MAF. Did I miss something?

 

Just installed a Dual Cone Cold Air Intake System and immediately got an Engine check light on, do I need to retune?

 

I think you just need a retune

 

I find it seriously difficult to imagine that a dual cone filter is causing a lean code.

Check for

- Unmetered air leaks between the MAF and TB
- Dirty oiled MAF Clean the MAF sensor wires with spray maf cleaner!!
- PCV system tubing and fitting leaks

I would NOT tune just for a damn air filter. A professional tune is $400-$500.. If thats all the mods that you are ever going to install, well, I guess that you can spend the cash for a tune. I doubt that you will see 10 HP from that filter.

I installed headers and a vararam in my 02 Z and never had any DTCs. I would be looking for something simple before you bless the issue off an an air filter change.

Bill

 

Please start a new thread instead of resurrecting a thread that is six years old.

http://forums.corvetteforum.com/foru...s-or-more.html