Still having MAF sensor burn off problems...
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Melting Slicks
Joined: Jun 2013
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Team Owner
Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
If the MAF & BO module behave properly on the bench it soulds like the ECM is not calling for burn off??
Have you tried running the engine till it goes closed loop before shut down to view the wire?
Have you tried running the engine till it goes closed loop before shut down to view the wire?
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Melting Slicks
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Melting Slicks
Joined: Mar 2008
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From: Santa Maria, CA
I think you're chasing a non-problem. The C-13 chart checks for a signal from the ECM as well as primary power. It sends you to Section B to look at other causes for whatever you are trying to troubleshoot.
Melting Slicks
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Thread Starter
Melting Slicks
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Race Director
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From: Anaheim CA
My '86 ECM has these parameters for MAF burnoff failure:
LC223: FCB 95 ; Fail burnoff test if ADC > 1.90 VDC
LC224: FCB 20 ; Fail burnoff test if ADC < 400 mVDC
Yours should be similar, if not the same. These are the voltages on the MAF output, not the voltages on the burnoff wire.
The schematic for the burnoff module clearly shows "BURN-OFF CONTROL" and it appears to apply 12 volts to the MAF sensor wire through a relay. The burnoff relay might not be working or have dirty contacts.
Have you looked at the PC board inside the MAF burnoff module? There might be burned components or bad solder connections. This post has a bunch of pictures of what to expect:
http://forums.corvetteforum.com/1571196606-post1.html
LC223: FCB 95 ; Fail burnoff test if ADC > 1.90 VDC
LC224: FCB 20 ; Fail burnoff test if ADC < 400 mVDC
Yours should be similar, if not the same. These are the voltages on the MAF output, not the voltages on the burnoff wire.
The schematic for the burnoff module clearly shows "BURN-OFF CONTROL" and it appears to apply 12 volts to the MAF sensor wire through a relay. The burnoff relay might not be working or have dirty contacts.
Have you looked at the PC board inside the MAF burnoff module? There might be burned components or bad solder connections. This post has a bunch of pictures of what to expect:
http://forums.corvetteforum.com/1571196606-post1.html
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
My '86 ECM has these parameters for MAF burnoff failure:
LC223: FCB 95 ; Fail burnoff test if ADC > 1.90 VDC
LC224: FCB 20 ; Fail burnoff test if ADC < 400 mVDC
Yours should be similar, if not the same. These are the voltages on the MAF output, not the voltages on the burnoff wire.
The schematic for the burnoff module clearly shows "BURN-OFF CONTROL" and it appears to apply 12 volts to the MAF sensor wire through a relay. The burnoff relay might not be working or have dirty contacts.
Have you looked at the PC board inside the MAF burnoff module? There might be burned components or bad solder connections. This post has a bunch of pictures of what to expect:
http://forums.corvetteforum.com/1571196606-post1.html
LC223: FCB 95 ; Fail burnoff test if ADC > 1.90 VDC
LC224: FCB 20 ; Fail burnoff test if ADC < 400 mVDC
Yours should be similar, if not the same. These are the voltages on the MAF output, not the voltages on the burnoff wire.
The schematic for the burnoff module clearly shows "BURN-OFF CONTROL" and it appears to apply 12 volts to the MAF sensor wire through a relay. The burnoff relay might not be working or have dirty contacts.
Have you looked at the PC board inside the MAF burnoff module? There might be burned components or bad solder connections. This post has a bunch of pictures of what to expect:
http://forums.corvetteforum.com/1571196606-post1.html
Thread Starter
Melting Slicks
Joined: Jun 2013
Posts: 3,065
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I guess that means it's bad right? I would test the resistance on it but some wiring diagrams say Solid State do not measure resistance, for like the ECM and some other modules. It doesn't say it for the Burn Off module but it does say Solid State on the diagram.
Race Director
Joined: Apr 2002
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From: Anaheim CA
That looks like solder flux to me (electronic engineer for a LONG time). It appears the relay was replaced but the flux was not cleaned off. You can clean it with alcohol.
Pro
Joined: Mar 2013
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From: Indiana
Cliff:
I'm also an I&E Tech and thought the same thing when I saw the pic. It looks like someone replaced the relay and didn't clean off the flux. Should clean off easily.
DanielRicany:
If this board is mounted in a position where you can see it working with the cover off you could watch the relay to make sure it pulls in. Also you might check the main contact to make sure its clean since its exposed.
I'm also an I&E Tech and thought the same thing when I saw the pic. It looks like someone replaced the relay and didn't clean off the flux. Should clean off easily.
DanielRicany:
If this board is mounted in a position where you can see it working with the cover off you could watch the relay to make sure it pulls in. Also you might check the main contact to make sure its clean since its exposed.
Drifting
Joined: May 2006
Posts: 1,428
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From: Chewelah Wa
You can measure solid state stuff if you have the right meter with a 10 megohm internal resistance. My cheap Walmart DVM has 10 meg. The "corrosion" you see is flux that has been getting hot at those solder joints. That is why both have the same thing, since it is used. I liked Hooked's idea.....you manually burned off the wire already, does it run any different?