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About a month ago I picked up a 2006 ss/sc. When bought there was only one code for an o2 sensor. A couple days ago my fuel economy tanked and i got a new code for the MAF near the airbox.
Today i popped out my headlight and was ready to clean the MAF. Come to see the airbox has been replaced with a cone filter. So now i have nowhere to mount the MAF. I then noticed the MAF wasnt even in the car, let alone gone bad, and i have an empty plug.
My questions are:
1) how could this have been hidden when i bought the car?
2) how woukd it take so long to present itself?
3) once i buy a new MAF where/how should I moint it?
I don't know how you wouldn't have noticed it running rough (if it will even idle) without a MAF installed. It should also throw a code almost instantly. You sure you that maybe it is on the bottom side of the intake or somewhere you can't see it?
In theory it should default to speed density without a maf plugged in but also should have set a code earlier. Is it tuned? Its possible with the o2 code that the ecm may not have ran the maf monitor checks until now but its still strange.
Pictures of engine bay and intake area are needed. It's possible in the LSJ tune to set it to run VE or speed density, but it shouldn't of suddenly started running crappy and thrown a code for a missing maf.
I was just going off how mine acted without a MAF but I'm pretty sure my Trifecta tune was setup to run mainly off the MAF. Without the sensor plugged in mine ran like garbage.
In stock form the lsj runs VE until 5500 or something like that. There is some blending that occurs earlier between VE and MAF, but the VE table is the main driver
I don't know how you wouldn't have noticed it running rough (if it will even idle) without a MAF installed. It should also throw a code almost instantly. You sure you that maybe it is on the bottom side of the intake or somewhere you can't see it?
Clearly AS SAID it was runnig fine and only had one code for o2 sensor. Do you really think i wouldnt look around?
Pictures of engine bay and intake area are needed. It's possible in the LSJ tune to set it to run VE or speed density, but it shouldn't of suddenly started running crappy and thrown a code for a missing maf.
You sound like you know things unlike others who tried to help. I took a couple pics for you
Chill, he's going from experience with a different ECU.
I was being respectful. Of course i would look to see if it ended up anwhere else, however i said there was even there. (Yes an empty plug as shown in pics above) I do not like being made to look stupid for missing something that wasnt even happening. The car was running fine, proper idle, pulled all the way to red line, and had decent fuel use while doing so. Also as stated, this issue happened almost a month after having the car.
Last edited by Little/Nobody; 04-22-2019 at 04:27 PM.
Reason: Typo
Your maf should be on the backside of that tube in the picture then, Here is a picture for reference. Its hard to see from up top where your looking. You should be able to feel around the tube and feel it, if not and the tube is completely smooth then someone has swapped it out. If that was the case then I would suspect your car has a tune on it and is supposed to ignore the sensor, which in that case sounds like a poor tune.
It almost looks like the previous owner removed the lower portion of the intake. When you had it on a test drive before buying did you row the gears to redline?
^That's what im thinking as well. Here is another that shows how its supposed to be from the factory. Take the filter off and see if the tube is cut somewhere like the previous pic (common airbox mod)or if they put a elbow to replace the whole box. (#4 is the sensor for reference)
Your maf should be on the backside of that tube in the picture then, Here is a picture for reference. Its hard to see from up top where your looking. You should be able to feel around the tube and feel it, if not and the tube is completely smooth then someone has swapped it out. If that was the case then I would suspect your car has a tune on it and is supposed to ignore the sensor, which in that case sounds like a poor tune.
I dont have the piece between your filter and tube. It's just filter on intake...
It almost looks like the previous owner removed the lower portion of the intake. When you had it on a test drive before buying did you row the gears to redline?
Yes a few times to test, as well as power pulls after purchase to 200+
Your maf should be on the backside of that tube in the picture then, Here is a picture for reference. Its hard to see from up top where your looking. You should be able to feel around the tube and feel it, if not and the tube is completely smooth then someone has swapped it out. If that was the case then I would suspect your car has a tune on it and is supposed to ignore the sensor, which in that case sounds like a poor tune.
hmmm, stock pulley and injectors. my gut instinct would be that it doesnt have a tune to correct for the lack of maf. how it would have run this long without setting a code (should have had multiple codes for the maf, such as open/short, low signal, and iat1 codes for open/short as its part of the maf) and running just fine is beyond me, but i cant see someone hacking on the cheapest cone filter they can find and then paying to have the car tuned, all while on a stock pulley and injectors.
hmmm, stock pulley and injectors. my gut instinct would be that it doesnt have a tune to correct for the lack of maf. how it would have run this long without setting a code (should have had multiple codes for the maf, such as open/short, low signal, and iat1 codes for open/short as its part of the maf) and running just fine is beyond me, but i cant see someone hacking on the cheapest cone filter they can find and then paying to have the car tuned, all while on a stock pulley and injectors.
Exactly why this makes no sence to me unless they where careless and left it hanging and it unplugged itself
Im going back to thinking that since you had the o2 codes the cel was on and the ecm was not able to finish the maf monitors correctly to set the code, thus it stayed in ve/speed density mode. @ECaulk is correct on the table setup, I was able to look up gm service information and find there is 4 modes of operation for intake airflow measurement. The first 3 use speed density as the main calculation with the 3rd using the maf as a secondary input. the last (high rpm but I don't know exactly when) switches over to using the maf as the primary table but does default to speed density when maf is not obtainable. At this point your looking at getting a stock intake assembly and clearing the codes. Also what o2 code do you have? O2 sensor problems will cause fueling issues and can also cause the engine to run like ****.
it should still set a circuit code as soon as the key is turned on, regardless of what other codes are there. if the maf was plugged in just hanging there the car should have had some serious running issues.
that aside, my recommendation would be to move towards the fix. your going to need to get a maf sensor and an intake of some sort. if you plan to leave the car stock i would try and track down a factory airbox and either leave it alone, or do the airbox mod. if your going to mod the car with things that will involve ecm tuning (injectors, pulleys, etc) then feel free to go with whatever cold air intake you like. keep in mind that most cold air intakes will change the flow characteristics of the maf and its ideal to have the car tuned for the intake, just throwing it on the car generally causes the fuel trims to trend lean and you will eventually get a check engine light, p0171- o2 bank 1 lean. the code for the most part is caused by the fuel trims at light throttle cruise being high and your in very little danger of having any major issues, aside from going mad staring at a check engine light.
it should still set a circuit code as soon as the key is turned on, regardless of what other codes are there. if the maf was plugged in just hanging there the car should have had some serious running issues.
that aside, my recommendation would be to move towards the fix. your going to need to get a maf sensor and an intake of some sort. if you plan to leave the car stock i would try and track down a factory airbox and either leave it alone, or do the airbox mod. if your going to mod the car with things that will involve ecm tuning (injectors, pulleys, etc) then feel free to go with whatever cold air intake you like. keep in mind that most cold air intakes will change the flow characteristics of the maf and its ideal to have the car tuned for the intake, just throwing it on the car generally causes the fuel trims to trend lean and you will eventually get a check engine light, p0171- o2 bank 1 lean. the code for the most part is caused by the fuel trims at light throttle cruise being high and your in very little danger of having any major issues, aside from going mad staring at a check engine light.
Originally Posted by Kolt
Im going back to thinking that since you had the o2 codes the cel was on and the ecm was not able to finish the maf monitors correctly to set the code, thus it stayed in ve/speed density mode. @ECaulk is correct on the table setup, I was able to look up gm service information and find there is 4 modes of operation for intake airflow measurement. The first 3 use speed density as the main calculation with the 3rd using the maf as a secondary input. the last (high rpm but I don't know exactly when) switches over to using the maf as the primary table but does default to speed density when maf is not obtainable. At this point your looking at getting a stock intake assembly and clearing the codes. Also what o2 code do you have? O2 sensor problems will cause fueling issues and can also cause the engine to run like ****.
@Kolt assuming my high rpm pulls is what caused the switch over, how to I switch is back. Im planning to sell the car and dont want to dump money into it. I can get an airbox if i must, but would prefer not to. When i bought the car it had the p0171 code that @Sharkey mentioned from the cone filter but that was all. Now i have all the MAF codes.
04-20-2019, 08:52 PM
