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Smog Verification


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I purchased my 02A back in January and noticed on past service receipts I was given that the EGR valve has been removed. I just wanted to verify with those who know that the EGR valve is in the middle left of picture #1. 

Then in picture #2 are those the dash pots with the red, white and black caps?  

I have a fairly good running stock carburetor engine and would be interested to hear what to expect if I did the smog delete. After getting the Solex rebuilt the only problem I currently have, other than the gas pedal coming off today on my way to work, is a non-working high idle at startup and some hesitation when accelerating during the first 2-3 minutes of warmup. 

Thanks in advance for your help. 

John in Colorado 



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The EGR Valve is the round thing just left of your Carb in the first picture.  In the second picture, those are your smog electro-mechanical valves, also part of your emission system.  All of that stuff can go in a smog delete, except 1976 car in CA and other states that still require testing for cars older than 1976.


You appear to have a very complete smog system, even the dashpot for the two barrel Solex which people usually delete when they eventually replace the Solex with a Weber 32/36.  Pulling all the smog stuff really frees up the car and improves the performance, but there is a lot to say for originality.  It really depends on what camp you are in.  Some 1976 California owners will want that complete smog system as spares.



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1970 BMW 1600 (Nevada)



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John, Looks like you found a really complete, well kept original. Is this a '75 or a '76 Calif. car?

The high idle at start-up may be caused by a disconnected vacuum line from the dashpot to the white electro-valve, or from the valve to the intake manifold. The dashpot allows the throttle to return to the idle position when manifold vacuum is applied. Without vacuum, the idle speed will be about 1500 RPM.

If you can de-smog this car in Colorado, my first change would be to remove the thermal reactor (big-bulky exhaust manifold). 

Then remove the EGR filter (under the intake manifold), EGR valve, and EGR control valves (see picture). Be sure to plug the EGR hose connection to the manifold. Keep all your smog parts....just in case.


02A Smog.jpg


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Thanks to both of you for the information. It’s a 1975 with 69k miles. My idle problem is low idle at start along with serious hesitation when giving it gas. After a couple minutes it’s running like a finely tuned clock. I was thinking fast idle cam but will check all the hoses. The smog delete is on my list after door cards, bumper tuck and heater control valve. It’s fun until you break something and then have to spend more money. 

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2 hours ago, Jdddrigot said:

My idle problem is low idle at start along with serious hesitation when giving it gas.

I had that problem with my '73 not long after I bought it in 1978.  It's related to the choke not performing one of its two functions, restricting the air flow via the choke plates in the carb throats and increasing the idle while the engine is cold.  


When starting from cold, you need to "set" the choke by flooring the accelerator pedal once or twice before starting.  That will close the choke plates, and re-set the fast idle cam.  Then when the engine starts, it should be idling about 1500 rpm; as the engine warms up, the choke plates gradually open, and the fast idle cam ratchet mechanism retracts, allowing the idle to gradually return to its normal 800 or so rpm.  Yours isn't.  


Presuming it isn't simply stuck, what has probably happened is that the teeth on the ratchet mechanism that catches the throttle stop have worn, and the throttle stop drops back to its normal 800 rpm idle instead of staying at the higher rpm required by a cold engine to prevent stalling.  That will also cause the cold engine hesitation when accelerating.   At least that was what was happening to mine, and my car had around 60-65k miles at the time.


I tried filing the teeth on the ratchet deeper; didn't help.  I even made a new ratchet piece (hand-filed).  That didn't work either, and the part wasn't available separately.  Even back then a new choke assembly was $85; a whole new Weber 32/36 was around $90.  With a manual choke.  Guess what I did.  


If that proves to be your problem and you want to keep things stock, see if you can find a derelict Solex 2 barrel (they're common) and salvage the choke assembly off it.  Or buy a Weber.  One final note--the second barrel on the Solex is vacuum operated (that big round thing attached to the carb that says "SOLEX") and the diaphragm is NLA, at least AFAIK...


Good luck.




'69 Nevada sunroof-Wolfgang-bought new
'73 Sahara sunroof-Ludwig-since '78
'91 Brillantrot 318is sunroof-Georg Friederich 
Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette) & Kermit, the Bugeye Sprite

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Thanks Mike. While doing my research I had seen your earlier post and felt a little defeated after seeing all your efforts on the fast idle cam for naught. Now I just need to find that fast idle cam to see what I’m up against. 

So funny, when I tried stepping on the pedal yesterday to set the choke it fell off!  I’ll spend some time on it this weekend looking at your suggestions. Plus I’m hoping to restore one door/door card. 

Stay healthy. 


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23 hours ago, Jdddrigot said:



In the later cars with the coil mounted in the forward position, there is a resistor wire inside the blue bundle running to the coil.  It is there to give a total of 3 ohms of resistance to a stock Bosch black coil.  You have a blue coil, which is typically internally resisted, so it does not need that resistor wire. 


The resistor wire has clear (yellowed) insulation, so it is easy to spot.  If you find that's what you have there, you can either run another wire in its place to give a full 12V, or switch to a stock coil.  Some people remove the resistor wire, but it seems like you might as well leave it there, so you can run a black coil in the future if you want to.



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