smog check failure...
Oh wow. AFM tweaking is popular in the E28 crowd, but I tried it one time on an 80 E24, same FI as E12, just two notches and it would go into occasional fits of almost not running at all. It was either fine with no change or massively rich. I think you're looking at it wrong for smog with a smooth idle, I think you would want more an O2 reading of .45-.5 open loop warmed up. Smooth idle isn't clean. Back in the days of carbs I found I could usually get very good readings for smog with leaning the crap out of them with the idle mixture screw. I'd just keep turning it in and raising the idle speed until it almost wouldn't run, then back off a little. I got good numbers that way, not with it running nice and smooth. Different systems of course, but same principle I think.
Mike W.
02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
02 525ita. Wife's, aka grocery getter
02 530i. New to the fleet, 3 pedals.
03 QX4, AKA the Datsun. Finally got the 4WD vacationmoble to stop smoking.
07 Xterra. Still on the DL, a purchase from hell.
-
Robert Bondi
- Posts: 403
- Joined: Sun Jan 11, 2009 12:33 am
- Location: Austin, TX
PASSED emissions in Albuquerque!
Hey Mike,
I was thinking the same thing - smoother idle after AFM spring loosening seems like the wrong way. Then again, sometimes the O2 sensor works against you. On a 530i, a massive vacuum leak means great gas mileage, albeit with a crappy idle. With the 528i, apparently the O2 sensor can easily overcompensate for the leak and make it way too rich.
Anyway, I just passed this morning. Here are the numbers against 500 ppm HC and 5% CO limits:
low idle, 981 RPM: 139 HC, 0.78 CO
high idle, 2265 RPM: 37 HC, 0.83 CO
I run a rebuilt, basically stock 3.0L with 528i FI, no cat, heated 4-wire O2 sensor sampling cylinders 1-3 with Euro manifolds and downpipes.
This is the list of actions between failed and passed emissions tests:
1. visual inspection for exhaust leak
2. compression check on all cylinders
3. tested FI temp sensor
4. check grounding and ambient air vent on O2 sensor
5. replaced all plugs (Bosch WR9DS)
6. replaced O2 sensor (Bosch 13275)
7. Redline SI-1 fuel treatment
8. used compressed air to check for exhaust and intake leaks - large
leaks discovered at valve cover corner and oil filler cap - fixed both w/ UltraBlue silicone
9. cut 6 new exhaust manifold gaskets from Mr Gasket 5961 material
10. adjusted all valves to loose 0.012"
11. new valve cover gasket and crankcase breather hose
12. AFM spring adjustment (loosened 17 teeth)
13. oil change
14. tuning:
a. ignition timing (removed the usual advance)
b. throttle body adjustment via FAQ procedure
c. idle set screw --> 950 RPM
d. AFM CO screw - ended up 8.5 turns out
Maybe I loosened the AFM spring a bit much to end up 8.5 turns out on the
CO screw, but the combination appeared to work.
Apparently, they are about to move to a rolling exemption cut-off at 35 yrs here on emissions. My 1977 530i should be exempt next year!
I was thinking the same thing - smoother idle after AFM spring loosening seems like the wrong way. Then again, sometimes the O2 sensor works against you. On a 530i, a massive vacuum leak means great gas mileage, albeit with a crappy idle. With the 528i, apparently the O2 sensor can easily overcompensate for the leak and make it way too rich.
Anyway, I just passed this morning. Here are the numbers against 500 ppm HC and 5% CO limits:
low idle, 981 RPM: 139 HC, 0.78 CO
high idle, 2265 RPM: 37 HC, 0.83 CO
I run a rebuilt, basically stock 3.0L with 528i FI, no cat, heated 4-wire O2 sensor sampling cylinders 1-3 with Euro manifolds and downpipes.
This is the list of actions between failed and passed emissions tests:
1. visual inspection for exhaust leak
2. compression check on all cylinders
3. tested FI temp sensor
4. check grounding and ambient air vent on O2 sensor
5. replaced all plugs (Bosch WR9DS)
6. replaced O2 sensor (Bosch 13275)
7. Redline SI-1 fuel treatment
8. used compressed air to check for exhaust and intake leaks - large
leaks discovered at valve cover corner and oil filler cap - fixed both w/ UltraBlue silicone
9. cut 6 new exhaust manifold gaskets from Mr Gasket 5961 material
10. adjusted all valves to loose 0.012"
11. new valve cover gasket and crankcase breather hose
12. AFM spring adjustment (loosened 17 teeth)
13. oil change
14. tuning:
a. ignition timing (removed the usual advance)
b. throttle body adjustment via FAQ procedure
c. idle set screw --> 950 RPM
d. AFM CO screw - ended up 8.5 turns out
Maybe I loosened the AFM spring a bit much to end up 8.5 turns out on the
CO screw, but the combination appeared to work.
Apparently, they are about to move to a rolling exemption cut-off at 35 yrs here on emissions. My 1977 530i should be exempt next year!
Robert
77 530i
77 Euro 528
77 530i
77 Euro 528