LH 2.2 MAF/CO adjustment LED (85-86 US)
01-18-2008, 06:16 PM
#16
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Hooked it up to a gas analyser at the tailpipe (no cats).
HC = 125
CO = .60
Oregon standard is HC 220, CO 1.0, at idle, so it would pass the test, but not the visual (check for cats only, hood closed).
When I first bought the car, I took it in, as is to see where it was at, and it got, with cats, HC 17, CO 0.0000.
HC = 125
CO = .60
Oregon standard is HC 220, CO 1.0, at idle, so it would pass the test, but not the visual (check for cats only, hood closed).
When I first bought the car, I took it in, as is to see where it was at, and it got, with cats, HC 17, CO 0.0000.
01-18-2008, 06:47 PM
#17
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Oddly, the emissions sticker on the hood specifies 0.6 ±0.2, with the O2 sensor disconnected. When I disconnected the O2 sensor, HC and CO went way up.
01-19-2008, 06:19 AM
#18
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My preferred method would be to adjust CO pot with O2 sensor disconnected. With the sensor disconnected the LH defaults to mid range of the O2 loop.
Then reconnect the O2 sensor. The LED may be introducing some offset due to its threshold voltage drop ? So the correct flashing cycle may be more asymetric....
The O2 loop has a reasonably wide range, so some offset is tolerable but best not to use up more of that latitiude than necessary.
Then reconnect the O2 sensor. The LED may be introducing some offset due to its threshold voltage drop ? So the correct flashing cycle may be more asymetric....
The O2 loop has a reasonably wide range, so some offset is tolerable but best not to use up more of that latitiude than necessary.
01-22-2008, 01:05 AM
#19
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Ken,
How old is the 02 sensor? I had difficulty passing NJ emissions last year after passing a couple of years earlier. A new O2 sensor was the fix - CO was back down to 0.00% and idle/driveability improved. Before you adjust the pot on the MAF, check the O2 readings.
Adam
How old is the 02 sensor? I had difficulty passing NJ emissions last year after passing a couple of years earlier. A new O2 sensor was the fix - CO was back down to 0.00% and idle/driveability improved. Before you adjust the pot on the MAF, check the O2 readings.
Adam
01-22-2008, 01:15 AM
#20
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Adam,
The O2 sensor is newish. With the cats installed, I'm sure the readings would be zero CO.
The LED is the O2 reading, processed by the LH. With the MAF set for an even flash, the CO is at the factory standard, pre-cat.
The O2 sensor is newish. With the cats installed, I'm sure the readings would be zero CO.
The LED is the O2 reading, processed by the LH. With the MAF set for an even flash, the CO is at the factory standard, pre-cat.
02-06-2008, 12:57 PM
#24
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I have the 84 S2 4.7 LH. With no oxygen sensors or cats. Would this procedure be used for my model as well?
Big AL in VA
84 928S2 Euro twin distributor monster
Big AL in VA
84 928S2 Euro twin distributor monster
Last edited by Big AL in VA; 02-06-2008 at 05:24 PM. Reason: changed model year from 82 to 84...typo
02-06-2008, 01:18 PM
#25
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The set idle speed to 675rpm with the adjuster on the throtlle assembley, just under the tie bar.
If the CO won't come up as high as 1% your MAF is badly aged and should be replaced.
02-06-2008, 01:49 PM
#26
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Because the euro LH2.2 doesn't have the 02 sensor, or idle control valve, it doesn't need, or have, the diagnostic connector.
04-08-2008, 01:46 PM
#29
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