: Air Intake issues...



Mobius
06-20-07, 12:29 PM
Hey guys, I'm getting a periodic check engine light. It only happens when I really give it throttle and sometimes it goes away, sometimes it doesn't. I had the local Caddy shop check the codes and got 4. One was the MAF, but it also said it passed it's last test. The other three were the three O2 sensors. Right now there is no light when I start up.

I changed the air filter to a drop in K&N filter, no CAI. The caddy tech says the K&N has damaged the MAF, but I don't believe him. K&N says that's an urban legend and no one has proven that the oil can damage the MAF. And if the MAF is damaged, why is it saying it passed the test.

Question is, how hard is it to change the O2 sensors if I need to. This is a 2003 EXT with no waranty left, so I like to do as much as I can to keep the cost down. (Caddy tech says MAF is $600 to replace, I can buy new for $150, etc.)

Next question is, will cleaning the MAF (with contact cleaner, not soap) resolve this intermittent issue? Do I need to get an aftermarket MAF because the PCM is not adjusting right to the K&N? Etc. Anyone else have this problem? I've seen a LOT of CAI's installed on this board and no one mentions problems with check engine lights due to MAF on any of them. Is my MAF bad?

Need some help if you can. Thanks.

hcvone
06-20-07, 01:05 PM
I have used oil type filters like K&N in all my C4's and C5's and never had an issue, you would have to load up the filter with oil to get a MAF error. You can clean it with contact cleaner, I have done it many times. If you have over 50k I would change the o2's, it will pay for itself in gas over the long run.

Mobius
06-20-07, 05:35 PM
I have used oil type filters like K&N in all my C4's and C5's and never had an issue, you would have to load up the filter with oil to get a MAF error. You can clean it with contact cleaner, I have done it many times. If you have over 50k I would change the o2's, it will pay for itself in gas over the long run.

103k on an 03! Well used, but not abused. Anyone know how hard it is to change the O2 sensors? Any tricks? Or is this a don't even bother have someone else do it?

Oh and K&N has results on their website where they way overloaded a filter with oil and ran the engine with no affect to the MAF at all. They claim no one has ever proven that their filters have ever caused a problem.

hcvone
06-21-07, 06:30 AM
I would change the O2's with your mileage, the problem is some times they "weld themselves in" to the exhaust due to how long they are in there, it's not a bad job depending on how "stuck" they are.

Mobius
06-24-07, 01:09 PM
Thanks for you help Carl. I bought a can of CRC MAF Sensor Cleaner and followed the directions. Cleaned very well and let it dry completely. BTW, when I pulled the MAF, there were a few "lint" like pieces stuck to the wires inside, I suppose that can't be good. Anyway, put it all back together and have not seen the engine light since. I even tried a couple WOT's on interstate on ramps to see what would happen. Nothing. That's the most common time I found the light coming on. So I suppose that problem is solved. Now I need to change out the O2 sensors.

Anyone know any significant difference between the OEM sensors and the universals? All I can find is that you have to clip wires on the universals. No one seems to say which is "better."

FRISBEE
06-26-07, 08:45 PM
Thanks for you help Carl. I bought a can of CRC MAF Sensor Cleaner and followed the directions. Cleaned very well and let it dry completely. BTW, when I pulled the MAF, there were a few "lint" like pieces stuck to the wires inside, I suppose that can't be good. Anyway, put it all back together and have not seen the engine light since. I even tried a couple WOT's on interstate on ramps to see what would happen. Nothing. That's the most common time I found the light coming on. So I suppose that problem is solved. Now I need to change out the O2 sensors.

Anyone know any significant difference between the OEM sensors and the universals? All I can find is that you have to clip wires on the universals. No one seems to say which is "better."

Go with OEM sensors or at the least Napa (sometimes oem just reboxed)
Its always good to clean the MAF so often if you live in the Southwest or any dusty climate(sp)

Mobius
06-27-07, 09:16 AM
Go with OEM sensors or at the least Napa (sometimes oem just reboxed)
Its always good to clean the MAF so often if you live in the Southwest or any dusty climate(sp)

From what I can tell, and I freely admitt I could be wrong, Bosch is the OEM manufacturer of the O2 sensors. Bosch has a universal O2 that is essentially the exact same sensor as OEM, it just doesn't have the OEM wiring plug. So you clip the wires on the OEM plug and insert the universal in it's place. Otherwise it's the same sensor exactly. But the difference is $60 vs $140 for the OEM. I can clip wires and I don't mind doing some soldering and splicing. I just can't find anything that says the OEM's are that much better other than you don't have to clip any wires. I don't mind convenience, but I've got to replace 7 of these things (2 vehicles) and at $80 a pop for convenience, I start to twitch a little.

Also, I believe Napa's are Bosch as well.

If anyone can say why I shouldn't get universals, other than it's easier to plug them in, I'm all ears. I mean, something like the universals only last 10K miles before they go bad, or they all have the wrong voltage, or something major like that.