2005 Buick Lesabre Not Passing Emissions. Help or Ideas needed.

[brad sweet]

Not sure if your model had it but they ran plastic intake plenums on the 3.8 and they would crack or leak at the gasket. Need to get it smoked to see if it (or other items) are leaking.

I believe this is the aluminum intake..not sure if when they plasticized it

 

[brad sweet]

This is what I am thinking too. P0170 and P0171 r 2 dtc codes that ur usually H02S (upstream) as opposed to catalyst monitors (downstream) after the cat. I thank 1 is bank one and the other is bank 2 if memory serves me correct. LOL

thats true but most of the o2 sensors dont need to be replaced usually something else causing the lean out and the end sensor is throwing the code..if it was a bank one rich code then the sensor has sent the system into open loop..but as every thing else in maintenance simple parts are often over looked..before replacing the O2 sensor

 

[YOTESHOOTER]

Had an issue with one we use to have, may not be any ones else's however ours came from leaving the gas cap off during gas fill up and allowing the engine to run while fueling up the car???

just a suggestion...

 

[brad sweet]

Had an issue with one we use to have, may not be any ones else's however ours came from leaving the gas cap off during gas fill up and allowing the engine to run while fueling up the car???

just a suggestion...

that will set of emissions and GM will send a gas cap code

 

[harrycalahan]

I believe this is the aluminum intake..not sure if when they plasticized it

Ive been out of the game for several years and dumped all the information I used to know. The last one I remember working on with a plastic plenum was 2004 Park Ave.

 

[nitrousfedlx]

thats true but most of the o2 sensors dont need to be replaced usually something else causing the lean out and the end sensor is throwing the code..if it was a bank one rich code then the sensor has sent the system into open loop..but as every thing else in maintenance simple parts are often over looked..before replacing the O2 sensor

Open loop, u mean when they r wide open for 180 seconds when u first start the car, then they never close?

 

[Wallace's]

Could be low fuel pressure which gm is known for bad pumps

I believe this is the aluminum intake..not sure if when they plasticized it

Google shows as a plastic one for this year. Plausible that it is cracked, but seems the intake failure on these cars leads to coolant in the crank case:

http://bernardsblog.blogspot.com/2008/12/gm-38l-plastic-composite-intake.html

 

[10thmountain]

Its the 0701 Code---Running lean....

 

[10thmountain]

A friend of mine runs a "Tuner " Shop we are going to really get into it tomorrow evening..

 

[brad sweet]

Google shows as a plastic one for this year. Plausible that it is cracked, but seems the intake failure on these cars leads to coolant in the crank case:

http://bernardsblog.blogspot.com/2008/12/gm-38l-plastic-composite-intake.html

quite possible that the EGR valve and plastic was not a smart combo..if loss of coolant is found then this may be part of the problem