PO171 Code
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 3,088
Likes: 1
From: NC
PO171 Code
Fuel Trim System Lean
2004 MN6 Coupe
Happened twice...First time was 5 miles after emissions test at DMV.
I was about 1/4 tank of gas and just about to stop when
"Check Engine" light comes on.
Got gas, cleared codes (already went to "H") and went on my way.
Then happened again the other day. Same thing. Got down to about
1/4 of gas and on pops the "Check Engine" light.
Same deal, filled up and drove home to do a few start/stop cycles.
Got the same P0171 H. Cleared OK.
Do you think it's possible when inspection guys pressurized the gas
tank and/or gas cap, that the cap is now damaged?
The gasket and cap "look" fine but the vent mechanism might be
faulty.
There's also the possibilty that I have an air leak around my intake
(Blackwing and carbon fiber bridge) but seems unlikely.
Anyone have similar issues?
...George
2004 MN6 Coupe
Happened twice...First time was 5 miles after emissions test at DMV.
I was about 1/4 tank of gas and just about to stop when
"Check Engine" light comes on.
Got gas, cleared codes (already went to "H") and went on my way.
Then happened again the other day. Same thing. Got down to about
1/4 of gas and on pops the "Check Engine" light.
Same deal, filled up and drove home to do a few start/stop cycles.
Got the same P0171 H. Cleared OK.
Do you think it's possible when inspection guys pressurized the gas
tank and/or gas cap, that the cap is now damaged?
The gasket and cap "look" fine but the vent mechanism might be
faulty.
There's also the possibilty that I have an air leak around my intake
(Blackwing and carbon fiber bridge) but seems unlikely.
Anyone have similar issues?
...George
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 3,088
Likes: 1
From: NC
Originally Posted by vettenuts
Do you have the screenless MAF on the 04? (Not sure if that is Z06 only). If yes, when did you install the Blackwing?
Still has the screen and BW is on for 2 years. This happened right
after the DMV inspection.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I didn't think they touched the tank with emissions checks. If it were the cap, I would think it would be both side throwing the code as well. Just read threw my service manual, first thing they state to check is fuel level because too low a level will throw the code. Maybe your sender is off a bit and the tank is lower than you think. What happens when you fill it, does it take about 3/4 tank of fuel or does it seem like more then that? Have your tried re-filling at 1/4 tank to see if it keeps the code from re-appearing?
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 3,088
Likes: 1
From: NC
Originally Posted by vettenuts
I didn't think they touched the tank with emissions checks. If it were the cap, I would think it would be both side throwing the code as well. Just read threw my service manual, first thing they state to check is fuel level because too low a level will throw the code. Maybe your sender is off a bit and the tank is lower than you think. What happens when you fill it, does it take about 3/4 tank of fuel or does it seem like more then that? Have your tried re-filling at 1/4 tank to see if it keeps the code from re-appearing?
I'm not sure if they presurrize3 the tank or not but they do stick a nozzle in it.
It's only happened twice and each time about 1/4 tank. The fill seems
normal and about as accurate as I can tell so I don't believe the gauge
or sensor is 1/4 tank off. As soon as I fill and check the codes, the code is "history" and then starting the car, the light goes off.
The easiest thing to do is change the cap and make sure no intake air leaks are present. I just wondered if the cap is marginal.
Team Owner
Joined: Jul 2004
Posts: 24,652
Likes: 298
From: NJ
St. Jude Donor '05-'08
Thread Starter
Melting Slicks
Joined: Nov 2001
Posts: 3,088
Likes: 1
From: NC
Originally Posted by Wicked Weasel
Thanks Bob...I think I've been running lean for awhile because I have noticed some pinging in the very warm weather.
Maybe time for an ECS tuning.
...G
