p0171 Bank one too lean

[carrotsnax]

I have gotten this code twice now and I only get it when at idle. A friend of mine said its probably my primary 02, but to be honest I have no idea.

Tried the whole search thing but the search on this forum is pretty lame.

Thanks

Brian

 

[speedin]

it should be the primary o2.

 

[Spiced MSP]

I have this code too along with P0172 air/fuel ratio rich bank 2

 

[Morticai]

Ok carrotsnax idk if this will fix your problem but it is for sure Spiced MSP's problem.

Under the intake manifold is a vacuum line with a 1way bypass valve going from Bank 1 to bank 2. If it is broken all the air will go into bank 1 (To Lean) And no air will go into Bank 2 (To Rich)

These pics were taken with a iphone so there crap but should at least give you an idea


Ok here is the bypass valve (broken)

The Red Circle is where you can take a mirror and see the actual vac line, The neon green is where the actual bypass valve and vac line are but under the top of the manifold

And here is an attempt to get a pic of my new one. (Tight fit)

 

[MSP2k3]

subbin for the pic as i have had this cel as well

 

[Morticai]

Pics are up.

 

[carrotsnax]

interesting thanks for the reply. I am also getting code p0660 intake manifold tuning...

Anything else to add to that since I am throwing another code?

thanks for the help

 

[Morticai]

Well due to the fact that Vac line is in the manifold it may fix your problem. I havnt ran into that code yet so I wouldn't know. Do you hear a loud hissing sound while your car is running comming from underneath your fuel rail?

 

[neox.286]

interesting thanks for the reply. I am also getting code p0660 intake manifold tuning...

Anything else to add to that since I am throwing another code?

thanks for the help

isn't that code usually associated with the butterfly valve actuators on the intake manifold not actuating properly? check to make sure that they are opening and closing on their own, I'll check my shop manual tomorrow to see if there is a for sure way to test that system to make sure it is working right

 

[carrotsnax]

No hissing or really anything out of the ordinary I hold 21-22 vacuum on my gauge. I do notice one thing though. That sometimes under part throttle cruise my Vics flaps will open and close at random sometimes.

I know that when the engine is running the vacuum diaphram and arm should be VERY difficult to push down, and easy to push when the engine is off and there is no vacuum.

I will check for any type of vacuum leak again though.

I think I am going to try a 02 sensor as I have a spare to try. Try that see what happens. I have noticed that my gas mileage has been suffering lately.

I drive my car in vacuum 90% of the time. I drive to and from work on the highway and dont really need or want to get into boost on the highway.

Also I did just install a Joep Fuel cut defender. I didnt get any of the codes until after installing it....If that means anything.

Thanks for the help fellas

 

[Spiced MSP]

Ok carrotsnax idk if this will fix your problem but it is for sure Spiced MSP's problem.

Under the intake manifold is a vacuum line with a 1way bypass valve going from Bank 1 to bank 2. If it is broken all the air will go into bank 1 (To Lean) And no air will go into Bank 2 (To Rich)

These pics were taken with a iphone so there crap but should at least give you an idea


Ok here is the bypass valve (broken)

The Red Circle is where you can take a mirror and see the actual vac line, The neon green is where the actual bypass valve and vac line are but under the top of the manifold

And here is an attempt to get a pic of my new one. (Tight fit)

Holy crap!!! thanks Morticai, I would have never looked for that. I will definitely check it out tomorrow and see what I find.

 

[Morticai]

Np man hope that fixs it let me know.

 

[Morticai]

No hissing or really anything out of the ordinary I hold 21-22 vacuum on my gauge. I do notice one thing though. That sometimes under part throttle cruise my Vics flaps will open and close at random sometimes.

I know that when the engine is running the vacuum diaphram and arm should be VERY difficult to push down, and easy to push when the engine is off and there is no vacuum.

I will check for any type of vacuum leak again though.

I think I am going to try a 02 sensor as I have a spare to try. Try that see what happens. I have noticed that my gas mileage has been suffering lately.

I drive my car in vacuum 90% of the time. I drive to and from work on the highway and dont really need or want to get into boost on the highway.

Also I did just install a Joep Fuel cut defender. I didnt get any of the codes until after installing it....If that means anything.

Thanks for the help fellas

I would mostly recheck your FCD to see if everything is installed correctly if you wernt running codes till after installing that.

 

[carrotsnax]

already checked it. Its pretty simple though, its non polarized so you can run current through it either way. It has 2 wires. One you ground, then one you hook up to pin / or the middle wire on the MAF.

 

[Morticai]

Humm another thing to try then would be to swap your fuel injectors. For ex Swap Bank 1 with Bank 2. Then clear the code if it comes back and is now running lean on Bank 2 its your fuel injector... Also when my bypass valve broke. It wasnt showing any Vac leak the only way I found it was I was spraying carb cleaner around my manifold and noticed my engine would rev when I would spray in that area.

 

[43975]

I have the same code P0171 after my Split second install and tune. I read many threads and all pointed to the EGR. so I replaced it....No luck. I took off the Split second and No CEL!! I drove that way for about a week the car was great. I put the Split second back on only soldering the wires in this time for a better connection....CEL came right back. Strangely enough with the split second on before the CEL comes back the idle sucks. The car will sit at a light for a few seconds OK then the idle drops and vac goes from 21-22 to 17-18 the car revs itself and the idle raises. Once the CEL pops back on the idle stays fine and she drives perfect.

 

[Spiced MSP]

I looked at the bypass valve under the top half of the manifold and it seems to be ok. I felt around on it and it seems to be intact, nothing broken or cracked or anything. I am going to try switching the fuel injectors and using carb cleaner too and see what happens.

 

[Morticai]

Interesting. Well I bought a "mystery msp" about a month and a half ago for real cheap. The only reason I did so was because I knew I had friends that live and breath MSP so I figgered what the hell ill buy it.

The problems it had were...
CEL P0171
The car wouldnt idle worth crap
Bank 1 was misfiring
Turbo would spool but wouldnt have any pull

and so on.

Well how I fixed the misfire which also can cause a P0171 is the Idle Control Valve was shot. It was running .05 ohms and was suppose to be 700-900ohms Once Neo and I had replaced that the car almost idled perfectly. What finnaly fixed the idle problem was the bypass valve.

So things I would check is

Test your Idle Control Valve to see if its working.
Also clean and check out your EGR ( I did that though and it didnt do anything)

And also try the fuel injector swap..

 

[kneedragger89]

i am having the same two codes P0171 and P0660 (spiced msp) did you ever figure it out

 

[carrotsnax]

My car will only throw a check engine light after letting it idle for cool down to turn off. When I let the car idle for 2 minutes or so it will turn on.

I am not running egr on my car and have been for a very long time. So egr is not a problem for me.

ZUKU26, your car sounds similar to mine.

I have gotten the P0171 every time I let the car idle for 2 minutes. Although every time I get the check engine light I do not get the P0660 code. I only get that once in a while.

My car idles pretty well. It idles the same as it did N/a.


I did have a injector leak about a month ago. when I was putting my new motor in I had a issue with one of my injectors going into the fuel rail..Sadly I got impatient and forced it in. It apparently slightly ripped it and it didn't start to leak until 5 months later. It didn't start leaking until the car was boosted for a month. I noticed the extra fuel smell around the car and investigated and solved the problem.