2007 Chevrolet Silverado 1500 Q&A
2007 Chevrolet Silverado 1500 Question: 2007 silverado check engine light. installed colde air intake. system too lean.
i installed a cold air intake on my 2007 silverado new body style 1500. check engine light is on and have diagnostic codes. system too lean. the filter is huge. If i installed a smaller filter (less airflow), would that solve the system being too lean issue? would make sense to me...big filter=lots of air, smaller filter=less air. just curious - Church1
If you are now going to try and reduce the air flow, why did you try to increase it to start with? Do you still have all the sensors like the MAF & IAT working as they should? What was wrong with the stock system? I just dont see the need for that add on. Never pay for itself. That's my opinion, i could be wrong! It's your truck, do what you want to. - pushrod
This isn't the first time that I have heard this and the potential answer can be difficult to grasp. The MAF sensor doesn't actually measure all of the air entering the engine, it is calibrated to measure a portion of it and that is supposed to give the computer an accurate representation of all of the air entering the engine. Saying this another way, picture all of the air flowing into the engine via the stock 3" pipe. At a given engine load it would be moving at a speed that the sensor reads accurately because the engineers calibrated it to do that. Now take that same sensor and put it into a pipe 10% larger, and with the same engine load as the first example, the air in the pipe would be moving 10% slower, so the sensor ends up under-reporting the airflow to the computer by that same 10%. Now that's actually the easy one, there is another that often occurs. Air has mass, and because of that has inertia. As it moves through the air filter and into the intake tube where the MAF sensor resides the engineers do everything they can to make it have a linear flow through the entire tube. But if turbulence occurs, especially if it is right at the MAF sensor, the sensor could experience a high spot, or a low spot in the density of the airflow. Turbulence/density issues are often erratic under different engine loads and it often takes plotting data in a scatter graph format to prove when it is occurring. So what do you do? The first choice is to re-install the original intake system, but I already saw that you discarded it. So that brings you to the second and tricky choice, I'll try and explain this the best that I can. Your solution might be to install a baffle in the tube exactly opposite of the MAF sensor. The aim is to decrease the cross-sectional diameter of the tube right at that point. That will speed up the airflow and increase the value that the sensor outputs for a given engine load. It's going to be a trial and error exercise, and you must be absolutely certain that the device remains secure and doesn't get ingested by the engine. To do that, you have to make it in a complex shape. It needs to have a curve to follow the profile of the pipe, and a second curve to make it rigid, and you still need angles to anchor it to the outside of the pipe. To attach it to the pipe, first draw a "smile" on the pipe to be the line that you have to cut. Three inches in length will be plenty. Bend a piece of tin to be the baffle in the shape of the smile that you cut. Then cut it to match the profile of the pipe and leave it about 1 3/4 inches high. Cut 3/8" ears and fold them every other one forward, and rearward. That will be the outside of it and prevent it from being able to be drawn into the pipe and make for an anchoring system. If you have the picture of what the baffle will look like, the first adjustment to it might be to ensure you physically clear the MAF sensor. Then you can secure it temporarily with duct tape. Now its all down to adjusting the size of the baffle to force the MAF sensor to read correctly and you will have to do some extensive driving under multiple conditions while tracking the long and short term fuel trims. If the sensor is over reporting, you'll have to start whittling it away. If it's still under-reporting you'll have to re-make it larger and start the process all over again. It's fun to re-engineer some things, but it can be very frustrating learning the ropes. Once you have the fuel trims accurate, you can then secure the baffle to the pipe, pop-rivets in about four of the tabs should do. Then seal it up with the duct tape again. HTH. - cardocIII