P0174,P0171 Codes...

Wicked · 03-18-2005, 08:01 PM

I have been getting codes for lean condition on both banks. The codes are triggered by long term fuel trims of over 20%.

After I put the supercharger on, my car ran great for a long time and it still does.

I guess it was about 6-8 months after adding the charger that I started getting the P codes for lean condition on both banks. The PGM I borrow from work shows a snapshot, it looks nearly identical everytime....same speed, tps, rpm, etc. The conditions I remember off the top of my head are 1800rpm, 50-something mph, 5th gear. I forget the load, TPS, etc but they all seem normal. By definition of the codes, my long term fuel trims are over 20%. I believe it happens in the contructions zones of I20, the only place I'd be going 50mph(my speedo is off so its actually 58mph)

I originally thought it was related to an exhaust leak on the driver side. But I fixed my exhaust leak, then got the code again, this time for both banks.

I have tried different O2 sensors with no luck. I also tried disconnecting my Air/fuel gage to make sure it wasn't creating an error in the O2 signal. Even if it had been it would onyl affect one bank anyway.

I guess the only other thing that may have changed is MAF position. I guess its possible that at that specific RPM/airflow the MAF gets confused.

I'm planning to get the car tuned soon hopefully and I want to clear up any items that might screw up the tunability.

Any ideas?

Wall96cobra · 03-18-2005, 08:22 PM

sounds like a vacuum leak to me

Wicked · 03-19-2005, 04:30 PM

Quote:

Originally Posted by Wall96cobra

sounds like a vacuum leak to me

I tried that. Haven't found any vacuum leak. I originally thought it might be related to the PCV system at first since it WAS a big vacuum leak. But I have that fixed now so I'm pretty sure thats not it. I thought that at first I looked all over for possibilities and not finding anything. Might be worth another loook though, just looking for other possibilities as well.

Interceptor, I have tried many changes and have disconnected the battery(usually overnight) everytime to reset the Keep Alive memory. Still keeps coming back.

uvbnhad · 03-19-2005, 01:32 PM

before you rack your brain and all that have you tried the simplest thing and unplugged your battery for a bit? After you did some stuff it might not have reset the computer and cleared the code. Just a suggestion before you really start diving in. I've seen it clear up several times before. Of course I could be wrong.

EDIT: Not saying this will absolutely fix your problem. Just might be worth trying before you really dive into trouble shooting.

Wicked · 03-20-2005, 02:07 PM

I checked the vacuum line to my boost gage and the vacuum line to my bypass valve and neither is leaking.

I think the only other thing is the idle air bypass, I may have taken that off once before. I will check it with some smoke to see if it leaks.

CrimsonRacing · 03-20-2005, 02:43 PM

speaking of codes.........

I pulled mine yesterday and returned 4

186-MAF injector pulsewidth voltage too low

157-MAF sensor voltage too low

could these be caused by the C&L?

The other 2 have been corrected.

Wicked · 04-07-2005, 05:30 PM

Quote:

Originally Posted by Wicked

I checked the vacuum line to my boost gage and the vacuum line to my bypass valve and neither is leaking.

I think the only other thing is the idle air bypass, I may have taken that off once before. I will check it with some smoke to see if it leaks.

I replaced the IAC gasket and it didn't solve the problem.

Only other thing that has changed along the way is the MAF position. I think this is the next place I will look.

Wicked · 03-20-2005, 07:44 PM

Dirty MAF element?

Wall96cobra · 04-08-2005, 06:31 AM

Hey Brad did you ever hook up the extender? Do you think you're still pegging the maf?

Wicked · 04-08-2005, 10:26 PM

Quote:

Originally Posted by Wall96cobra

Hey Brad did you ever hook up the extender? Do you think you're still pegging the maf?

Nope, waiting for a tune. Its wired in but has the dummy coupler in place.
The problem is not related to peggging maf as it occurs at low rpm, low load, cruising.

86GT, I agree about the exhaust leak/both banks not being the problem.
I am thinking the MAF is a possibility. I can look at the EGR, but I have never messed with it on this car.

03-18-2005, 08:01 PM	#1
Wicked Friends Join Date: Dec 2004 Location: Pell City, AL Posts: 1,371	P0174,P0171 Codes... I have been getting codes for lean condition on both banks. The codes are triggered by long term fuel trims of over 20%. After I put the supercharger on, my car ran great for a long time and it still does. I guess it was about 6-8 months after adding the charger that I started getting the P codes for lean condition on both banks. The PGM I borrow from work shows a snapshot, it looks nearly identical everytime....same speed, tps, rpm, etc. The conditions I remember off the top of my head are 1800rpm, 50-something mph, 5th gear. I forget the load, TPS, etc but they all seem normal. By definition of the codes, my long term fuel trims are over 20%. I believe it happens in the contructions zones of I20, the only place I'd be going 50mph(my speedo is off so its actually 58mph) I originally thought it was related to an exhaust leak on the driver side. But I fixed my exhaust leak, then got the code again, this time for both banks. I have tried different O2 sensors with no luck. I also tried disconnecting my Air/fuel gage to make sure it wasn't creating an error in the O2 signal. Even if it had been it would onyl affect one bank anyway. I guess the only other thing that may have changed is MAF position. I guess its possible that at that specific RPM/airflow the MAF gets confused. I'm planning to get the car tuned soon hopefully and I want to clear up any items that might screw up the tunability. Any ideas? __________________ 2001 Cobra 'Vert Procharged and Intercooled 455rwhp/441rwtq Work Car: 2005 Honda Odyssey 400 whp Turbo V6, 6-speed, full cage, H&R Suspension, Brembo Brakes

03-18-2005, 08:22 PM	#2
Wall96cobra ooooo cake!!! Join Date: Dec 2004 Location: Saks, AL Posts: 1,630	Re: P0174,P0171 Codes... sounds like a vacuum leak to me

03-19-2005, 01:32 PM	#4
uvbnhad Friends Join Date: Mar 2005 Location: McCalla Posts: 1,241	Re: P0174,P0171 Codes... before you rack your brain and all that have you tried the simplest thing and unplugged your battery for a bit? After you did some stuff it might not have reset the computer and cleared the code. Just a suggestion before you really start diving in. I've seen it clear up several times before. Of course I could be wrong. EDIT: Not saying this will absolutely fix your problem. Just might be worth trying before you really dive into trouble shooting.

03-20-2005, 02:07 PM	#5
Wicked Friends Join Date: Dec 2004 Location: Pell City, AL Posts: 1,371	Re: P0174,P0171 Codes... I checked the vacuum line to my boost gage and the vacuum line to my bypass valve and neither is leaking. I think the only other thing is the idle air bypass, I may have taken that off once before. I will check it with some smoke to see if it leaks. __________________ 2001 Cobra 'Vert Procharged and Intercooled 455rwhp/441rwtq Work Car: 2005 Honda Odyssey 400 whp Turbo V6, 6-speed, full cage, H&R Suspension, Brembo Brakes

03-20-2005, 02:43 PM	#6
CrimsonRacing Comfortably NUMB Join Date: Dec 2004 Location: ALIVE AGAIN Posts: 1,704	Re: P0174,P0171 Codes... speaking of codes......... I pulled mine yesterday and returned 4 186-MAF injector pulsewidth voltage too low 157-MAF sensor voltage too low could these be caused by the C&L? The other 2 have been corrected. __________________ '02 GT....just another money pit.

03-20-2005, 07:44 PM	#8
Wicked Friends Join Date: Dec 2004 Location: Pell City, AL Posts: 1,371	Re: P0174,P0171 Codes... Dirty MAF element? __________________ 2001 Cobra 'Vert Procharged and Intercooled 455rwhp/441rwtq Work Car: 2005 Honda Odyssey 400 whp Turbo V6, 6-speed, full cage, H&R Suspension, Brembo Brakes

04-08-2005, 06:31 AM	#9
Wall96cobra ooooo cake!!! Join Date: Dec 2004 Location: Saks, AL Posts: 1,630	Re: P0174,P0171 Codes... Hey Brad did you ever hook up the extender? Do you think you're still pegging the maf?