Check Engine Light wont go off
#1
10-02-2001 | 12:56 AM
Thread Starter
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Senior Member
Joined: Mar 2001
Posts: 401
Likes: 0
From: augusta, GA
Check Engine Light wont go off
after reading a few posts about removing the small rectangle metal plate on the back of the MAF, i went out and took mine off....truck cranked right up and i torqued it a little no problem...well today about 150 miles later the engine light pops on. i know it is because of taking out that plate...so what can i do about it? i dont want to put the plate back on if i can help it......
#2
10-02-2001 | 11:41 AM
Technical Article Contributor
Joined: Dec 1997
Posts: 9,417
Likes: 11
From: Windsor,Ontario,Canada
Bullitt,
Disconnect the battery and reset the PCM. If the SES comes back on you have to determine what is causing it. Have the PCM scanned for codes. Once you know for sure what the code(s) is(are) you can get them looked after. The odds are it is because of the MAF sensor. Check out http://www.tccoa.com/articles/intake/index.html#
There is alot of info on the MAF.
One thing people don't understand is the MAF. It sends a voltage signal to the PCM. This signal is interpeted along with other sensor input and the PCM opens the injectors for a predetermined time. When you open up the MAF and allow more air to flow you are creating a lean condition because the PCM doesn't know that more air is getting in the engine. This will trigger the O2 sensors and the PCM will richen up the mix and in theory this will add power to the engine. If the heated wires in the MAF are exposed to more air flow you can easly exceed the
parameters of the PCM and cause a code to be set. This is most likely what happened or you may have damaged the wires in some way.
Regards
Jean Marc Chartier
Disconnect the battery and reset the PCM. If the SES comes back on you have to determine what is causing it. Have the PCM scanned for codes. Once you know for sure what the code(s) is(are) you can get them looked after. The odds are it is because of the MAF sensor. Check out http://www.tccoa.com/articles/intake/index.html#
There is alot of info on the MAF.
One thing people don't understand is the MAF. It sends a voltage signal to the PCM. This signal is interpeted along with other sensor input and the PCM opens the injectors for a predetermined time. When you open up the MAF and allow more air to flow you are creating a lean condition because the PCM doesn't know that more air is getting in the engine. This will trigger the O2 sensors and the PCM will richen up the mix and in theory this will add power to the engine. If the heated wires in the MAF are exposed to more air flow you can easly exceed the
parameters of the PCM and cause a code to be set. This is most likely what happened or you may have damaged the wires in some way.
Regards
Jean Marc Chartier
#3
10-02-2001 | 12:14 PM
Senior Member
Joined: Jul 2001
Posts: 1,109
Likes: 1
From: Nu Joizey
MAF
Bullit, I did the same thing because I wanted to cut out the post in the MAF but was worried about the check engine light coming on. I drove about 30 miles without getting the light so I cut it away from the housing. Came out real nice and no light since.
Some people have had this problem when oil fron a K&N filter found its may to the MAF sesnsor. You could also try cleaning the the MAF in addition to resetting the computer.
Good luck and let us hear how things turn out for you.
Some people have had this problem when oil fron a K&N filter found its may to the MAF sesnsor. You could also try cleaning the the MAF in addition to resetting the computer.
Good luck and let us hear how things turn out for you.
#4
10-02-2001 | 03:56 PM
Senior Member
Joined: May 2000
Posts: 1,002
Likes: 0
From: Oregon
JMC, you are not just letting more air into the engine when you remove the centerpost and back plate, but you are also metering more air.
If you look at the stock setup, the air goes into the sampling tube, then down the back of the center post through 2 90* bends. This will slow the amount of air into the sampling tube and make the meter less acurate as it is not metering 100% of the air that it could be.
If you read up on this, more air in means a leaner air/fuel mixture if all else is the same. pretty simple math there. Now when you make the element sample more air by removing the plate, you are then letting the computer then sample the proper ratio of air that is now flowing into the engine with the centerpost gone. There is a lot of debate, but testing shows that the meter stays within 1-2% of the actual correct measurements. It would seem that some computers are more sensitive to the increased flow than others. I have not had one problem and actually allows the engine to rev out to 4700 now before falling on its face because of the camshaft profile (previous 3500 because of the air restrictions).
If you look at the stock setup, the air goes into the sampling tube, then down the back of the center post through 2 90* bends. This will slow the amount of air into the sampling tube and make the meter less acurate as it is not metering 100% of the air that it could be.
If you read up on this, more air in means a leaner air/fuel mixture if all else is the same. pretty simple math there. Now when you make the element sample more air by removing the plate, you are then letting the computer then sample the proper ratio of air that is now flowing into the engine with the centerpost gone. There is a lot of debate, but testing shows that the meter stays within 1-2% of the actual correct measurements. It would seem that some computers are more sensitive to the increased flow than others. I have not had one problem and actually allows the engine to rev out to 4700 now before falling on its face because of the camshaft profile (previous 3500 because of the air restrictions).