first ime ever failed smog - 81 320i

[OLD MAN]

Ok so one of my e21s failed smog today - first time this has happened.

Test results see it is running way to rich : yet plugs read that mixture is spot on, they are light gray everywhere.

And the fuel mixture adjustment is .78v to .81v at the O2 sensor.

Bad reading are at 2,200 rpm

Timing is 25 at 2,400 rpm

15mph CO2 10.1 O2 2.4 HC 2257 CO 4.75 NO 478

25mph 12.3 O2 2.5 HC 2711 CO .77 NO 766

Also the fuel distributor adjust is really touchy it jumps from 1.9 to 7.9 with a little adjustment no way to adjust between these two adjustments.

Any ideas needed - thanks!

[EconomicHustle]

Bump because I go to deq on Thursday... Lol.

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[epmedia]

Ok so one of my e21s failed smog today - first time this has happened.

Test results see it is running way to rich : yet plugs read that mixture is spot on, they are light gray everywhere.

And the fuel mixture adjustment is .78v to .81v at the O2 sensor.

Bad reading are at 2,200 rpm

Timing is 25 at 2,400 rpm

15mph CO2 10.1 O2 2.4 HC 2257 CO 4.75 NO 478

25mph 12.3 O2 2.5 HC 2711 CO .77 NO 766

Also the fuel distributor adjust is really touchy it jumps from 1.9 to 7.9 with a little adjustment no way to adjust between these two adjustments.

Any ideas needed - thanks!

That HC is way up there. HC is 'raw' fuel, ie: weak sparks, vacuum leak or poor compression. Maybe wrong spark plug gaps or using fancy plugs instead of plain copper or silver plugs. Check the valve clearances too : .008" for high miles engine.

CO is the black exhaust soot.

The jumpy fuel mix may be from the meter plate not being level, ie: resting low.

[OLD MAN]

That HC is way up there. HC is 'raw' fuel, ie: weak sparks, vacuum leak or poor compression. Maybe wrong spark plug gaps or using fancy plugs instead of plain copper or silver plugs. Check the valve clearances too : .008" for high miles engine.

CO is the black exhaust soot.

The jumpy fuel mix may be from the meter plate not being level, ie: resting low.

Thanks I will check these things.

I have black exhaust on inside of pipes.

If feels like a lean miss but always starts right up cold or hot.

On the road it runs great through the gears and pulls hard.

[jaredmac11]

Move to TX

[OLD MAN]

Move to TX

Or just out of California!! LOL

- - - Updated - - -

What does the O2 sensor trickier?

[m60b30530i]

Could one of the injectors be leaking ? worst case induce a small vacuum leak to lean out the afr

[OLD MAN]

Could one of the injectors be leaking ? worst case induce a small vacuum leak to lean out the afr

This is the next test - check injectors.

Checked for vacuum leaks = none
Checked timing = good
ignition is good
o2 sensor seems good as I can adjust it to .79 to .8 volts - but it jumps around not a steady reading.


And again all four plugs were a dry light gray color which to me shows a slight lean condition? I am thinking a leaking injector would cause a darker wet plug?

[epmedia]

Another thought related to the high HCs.. maybe the centrifugal advance is advancing the timing more than it's suppose to, at lower rpms, ie: broken or stretched spring?

Check this, very informative.
https://www.smogtips.com/failed-high...carbons-HC.cfm

[mxl556]

The easiest and cheapest is a new 02 sensor. Then CAT converter. How old is the CAT converter? Check pre CAT CO/HC and compare with post CAT and see if CAT is doing anything..
02 sensor voltage will oscillate since frequency valve is at 50% cycle that affects mixture.
With known good 02 sensor try disconnecting the 02 sensor and see if it runs richer or leaner, it will tell you how to adjust the mix baseline.

Max

[OLD MAN]

Thank you all for your help!

Will let you know how it does in the retest.

[EconomicHustle]

Bump because I go to deq on Thursday... Lol.

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And I failed HC Testing as well, any help is appreciated. I think I'm going to follow some of the advice already given - however, if anyone thinks the above doesn't apply please feel free to chime in.

	HC STD	CO STD	CO_CO2	HC	CO	CO2	RPM
Readings:
Idle Results:	220	1	6	425	0.6643	12.3	NA
2nd Idle	220	1	6	544	0.746	12.1	NA

[epmedia]

And I failed HC Testing as well, any help is appreciated. I think I'm going to follow some of the advice already given - however, if anyone thinks the above doesn't apply please feel free to chime in.

	HC STD	CO STD	CO_CO2	HC	CO	CO2	RPM
Readings:
Idle Results:	220	1	6	425	0.6643	12.3	NA
2nd Idle	220	1	6	544	0.746	12.1	NA

Probably weak sparks. use only plain copper or silver plugs, gapped no bigger than .028" for the points ignition. If you still got the OE ballast wire, it's past due for replacement/retrofit. Also make sure that battery voltage is above 12.5 volts at idle speed. As mentioned earlier, make sure no vacuum leaks too!

Remember that HC is 'raw' fuel coming out the tail pipe and CO is black soot out the tail pipe.

Here's the link about HC again
https://www.smogtips.com/failed-high...carbons-HC.cfm

[MortyCrock]

And I failed HC Testing as well, any help is appreciated. I think I'm going to follow some of the advice already given - however, if anyone thinks the above doesn't apply please feel free to chime in.

	HC STD	CO STD	CO_CO2	HC	CO	CO2	RPM
Readings:
Idle Results:	220	1	6	425	0.6643	12.3	NA
2nd Idle	220	1	6	544	0.746	12.1	NA

Did you get the Cats nice and hot before you went? I failed once in my 325ix, then went back a few hours later after driving the piss out of it, and passed...

just a thought. I know Oregon is a lot less strict than CA, and that worked for me.

[EconomicHustle]

Probably weak sparks. use only plain copper or silver plugs, gapped no bigger than .028" for the points ignition. If you still got the OE ballast wire, it's past due for replacement/retrofit. Also make sure that battery voltage is above 12.5 volts at idle speed. As mentioned earlier, make sure no vacuum leaks too!

Remember that HC is 'raw' fuel coming out the tail pipe and CO is black soot out the tail pipe.

Here's the link about HC again
https://www.smogtips.com/failed-high...carbons-HC.cfm

Will do. I'm going to additionally replace the air filter as well as run her before I take her in. It was noted somewhere that it helps if the cat is hot before testing.

I was thinking it was terrible, however, I had to remind myself that we are talking about ppm.

Thanks for the advice. I also read that article earlier, thanks for the reference. I'll let you guys know when I give her a second run.

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[EconomicHustle]

Was already in the game plan

Did you get the Cats nice and hot before you went? I failed once in my 325ix, then went back a few hours later after driving the piss out of it, and passed...

just a thought. I know Oregon is a lot less strict than CA, and that worked for me.

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[epmedia]

Will do. I'm going to additionally replace the air filter as well as run her before I take her in. It was noted somewhere that it helps if the cat is hot before testing.

The '77-'79 (2.0) does not have a 'cat / O2 sensor', it has a unique exhaust manifold (reactor), air injection and egr. I just remembered the air injection plays a major role to reduce HCs at idle speeds. more on this later if all the other stuff is good.

*the reactor should be tested hot, just like a 'cat' tho.

[mxl556]

Higher numbers across the board may mean that the catalyst is no longer working and nothing is wrong with the adjustments, etc. They do have a limited lifespan, especially the aftermarket ones. If everything is working right and adjusted correctly I would start by replacing the 02 sensor which is cheap for our cars ($30). After the 02 sensor replacement mixture adjustments may need to be done. If that does not solve the problem then check the CO before and after catalyst and see if the catalyst itself is actually working.

Eve though there is no emissions testing for my car here in VT, I recently replaced my old beat up catalyst with the DEC replacement and was very satisfied with the fitment and performance. I believe it is a Magnaflow unit that comes with the downpipes and is a bolt on. It seems to have larger pipes and a high flow catalyst when compared to stock. Not cheap, especially for CA folks, but worked for me.

Max

[320iAman]

Catalytic converters get dated as CARB changes the standards, thus a new Catalytic Converter you'll pass.

Randy