Did a search, info is still light: What are the risks of running with a bad MAF or no MAF at all?
06-11-2004, 09:47 AM
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Did a search, info is still light: What are the risks of running with a bad MAF or no MAF at all?
Dealer wants $400+ to change the MAF. It's the second one on a car with 90k miles. Besides having the CEL light on, what are the other risks?
TIA-
Ernesto
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Ernesto
06-11-2004, 09:51 AM
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i disconnected my MAF and blew an intercooler...but my intercooler was probably damaged beforehand
by disconnecting the MAF i put too much pressure on the components of the turbo system.
06-11-2004, 10:24 AM
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Re: Did a search, info is still light: What are the risks of running with a bad MAF or no MAF at all
You are better off running with a bad one than having it disconnected. However, with a bad one you risk misfires and other potential emission related problems since it can't correctly calculate amount/rate of air passing through.
You may want to see if it can be claimed under any local emission warrantys. I know in Colorado I am covered 7/70 by Audi, but am covered up to 8 years (dont know about mile limitation) on emission components mandated by the state IIRC.
$400 isn't bad considering the dealer told me this would have been about a $700 repair.
You can try cleaning the MAF, it has inherent risks associated with it, but it may be worth a shot and buy time for you to justify saving the money. In my experiences with cleaning the MAF on my old 1.8T Passat it was always a crutch that would last about 3 - 6 months.
I didn't do it on my 2.7T because I knew it was covered.
You may want to see if it can be claimed under any local emission warrantys. I know in Colorado I am covered 7/70 by Audi, but am covered up to 8 years (dont know about mile limitation) on emission components mandated by the state IIRC.
$400 isn't bad considering the dealer told me this would have been about a $700 repair.
You can try cleaning the MAF, it has inherent risks associated with it, but it may be worth a shot and buy time for you to justify saving the money. In my experiences with cleaning the MAF on my old 1.8T Passat it was always a crutch that would last about 3 - 6 months.
I didn't do it on my 2.7T because I knew it was covered.
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06-11-2004, 11:03 AM
#8
Car runs in WOT or "open loop" mode. It's meant to run in closed loop most of the time.
It can't meter volume or temp of incoming air, so it assumes everything is being maxed out - just to be on the safe side. So the car is running rich. Since the ecu can't compare incoming air with what the 02 sensors are seeing, it can't adjust the mixture. Lots of extra fuel being dumped into the system may result in cat meltdown as the fuel goes down the pipes and hits the hot cat. Look for fouled spark plugs and poor running under certain conditions after running open loop for a while. Also a potential for excess turbo temps. You'll use a lot of gas. Probably can't pass smog.
Just remember that although it is in max mode, there may be conditions that will still cause the car to run too lean (heat, poor gas, etc), and it won't be able reduce the power output accordingly. Running lean often is a great way to destroy an engine.<ul><li><a href="http://www.carcraft.com/techarticles/78118/index4.html">http://www.carcraft.com/techarticles/78118/index4.html</a</li></ul>
Just remember that although it is in max mode, there may be conditions that will still cause the car to run too lean (heat, poor gas, etc), and it won't be able reduce the power output accordingly. Running lean often is a great way to destroy an engine.<ul><li><a href="http://www.carcraft.com/techarticles/78118/index4.html">http://www.carcraft.com/techarticles/78118/index4.html</a</li></ul>
06-11-2004, 11:14 AM
#9
MAF systems tend to...
....idle better than speed density systems.
It's there as a back-up in the 2.7T since they needed a MAP sensor anyway. It's really a good idea. I wouldn't run it for a long time, but you can do it for a week or so while you're waiting for a new MAF. It's better than running the car lean.
It's there as a back-up in the 2.7T since they needed a MAP sensor anyway. It's really a good idea. I wouldn't run it for a long time, but you can do it for a week or so while you're waiting for a new MAF. It's better than running the car lean.
06-11-2004, 11:17 AM
#10
Not on the 2.7T....
The 2.7T reverts to speed-density (MAP) readings using the MAP sensor and the IAT sensor. It still runs closed loop, AFAICT, below WOT. LTFT's still register.