P0171 after boost, need advice.

[JavaJoe_2]

You don't have a high flow fuel pump??

[RON]

You don't have a high flow fuel pump??

As far as throwing a LEAN CODE..

I had 5.5 lbs boost and Injen short ram with NO FUEL mods for 7 years (not even Jim's until recently) and never had a lean code. Not saying fuel mods aren't a good thing..just that his lean code isn't from lack of fuel with stock boost.

[atclate]

I don't have an upgraded fuel pump, but I installed the jim's fuel mod, and it seemed to help a little, but it's still coming back...

And again, I only see the CEL come up at idle, and my idle is not very regular. It sometimes idles at 800, sometimes at 700, and then it might pop back up to 800... I think there's something wrong with my idle... but then, I don't have EBC, so I might be having boost even at idle...

[Eye8Pussies]

A lack of fuel mode will make you blow your knock sensors before making you throw a lean code most likely. And from the weird idle that you are describing and the fact that you thrownthe codes at idle, it's time to start looking for vacuum leaks.

Usually vacuum leaks will also throw. Random misfire code, but bit always, so check carefully.

[atclate]

Cool thanks.
I read up about checking vacuum leak here: http://www.aa1car.com/library/vacleak.htm

I'll use a scan tool to see what my Short Term / Long Term Fuel Trim is at idle, and try to spray my aresol carburetor cleaner to suspecting leakage locations.

A lack of fuel mode will make you blow your knock sensors before making you throw a lean code most likely. And from the weird idle that you are describing and the fact that you thrownthe codes at idle, it's time to start looking for vacuum leaks.

Usually vacuum leaks will also throw. Random misfire code, but bit always, so check carefully.

[atclate]

I couldn't find any leaks by spraying starting fluid on places I think it could have a leak. However, I started to suspect that the throttle body butterfly valve is where it's leaking. I see a small gap between the valve and the throttle body. I wonder if there's a way to adjust it.

I tried loosening the throttle cable and there's still a small gap.

[atclate]

I re-cleaned my throttle body again tonight, and loosened the screw that adjusts the throttle plate position. The CEL still comes back...

But while I was cleaning my throttle body, I found out something that seemed a little strange. When I was looking into the supercharger while holding the throttle open, I saw an opening that was closed, which seems to be the bypass for the boost. Basically, when I moved the actuator that controls boost, I don't see the opening open at all. It just keeps shut. I wonder if it's supposed to open. Does anyone know? I hope I don't have a defective S/C...

http://solaraguy.com/viewtopic.php?t=14418
I found this old thread that another person seems to be having the same problem as I do, and basically, the mechanic installed his vacuum wrong, and from my understanding, he always gets boost because of that.
I wonder if I'm experiencing the same thing, except in my case, I have a different problem...

[atclate]

>_< Doesn't seem like a problem with my boost actuator... I tried forcing boost all the time and I do feel a difference...

While I was playing with my scan tool, I noticed that I don't get the code when I first start up. I only get that code after I've driven my car, and then the car comes to an idle.

[atclate]

I am able to reproduce the code reliably now.
The code gets thrown whenever my car is warmed up and then I come to an idle. Then I tried hooking up my scan tool and monitor the readings, I found something interesting.

- When my car is warm, and I turn off the car, and then start it, my O2 (Air Fuel since my car is Cali Spec) sensor reading is around 0.1V. Then I rev it a little, without going into gear, my reading is also around 0.1V.

- However, after I drove around the block slowly, and then come back to an idle, my reading pops up to 0.45V. I idled a little bit, 0.45V. I revved it a little, it's also 0.45V. All other readings are the same as if I just started the car, including short term and long term fuel trim.

With this information, I wonder if I can conclude I have a bad or dirty A/F sensor. Should I replace it or is there a way to clean it? Afterall, this stick http://solaraguy.com/viewtopic.php?t=16121 did mention that "Heated oxygen sensor malfunction" could throw this code, and my engine bay does get pretty hot.

[Akfahad]

^^could be worth a shot. Although a shop would be more able to specifically ID the problem. They'd be able to determine if it is indeed the heater on the O2 sensor, since the heater function on the sensor is designed to bring the O2 sensor into optimum operating temp ranges. If the heater is bad, you need to replace the whole sensor since they are both "as one unit" if you will.

[atclate]

To correct my findings, the voltage on the rear sensor was .45V, and the ones before the precat was .7V.
Thanks for your advice.

[atclate]

Finally figured out what the problem was. I was the INJEN!
When I use the INJEN, the air flow read from my scan tool is 0.3lb/min. When I use the stock intake, the reading is 0.4lb/min.

The air fuel ratio must have been offset by the deflated air flow reading caused by the increased diameter of the INJEN. I'm going to go back to stock.

[jetbtkng]

i have injens on all my yotas, one cai, two shotries, never thrown a code, one my ole ladies 4 banger, the cai is my 2000 lara 6 psi, the 3rd is my 02 lara with the shorty at 8psi, somthings not rite on your car, it could be the afs........

[atclate]

I checked the front A/F sensor, and it has the normal white powderish coating on it. I don't think it's the a/f sensor. If anything, I would think it's the MAF sensor, or my IAC valve...

[Eye8Pussies]

bad a/f or o2 sensor does not cause the ecu to throw lean codes- if it's malfunctioning, the car will run rich- quite the opposite of lean


and although it's not common on our cars, it is not uncommon for an injen intake to cause lean codes in a lot of other cars, so it's not a huge surprise

especially when you were able to read the live data for the MAF sensor

and it wouldn't be your iac valve either since that doesn't change just because you have the injen intake on.

That, and if your iac valve is the culprit, you would have a lot of stumbling at idle as well (which I don't think you really described)