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Fresh engine rebuild - nasty fumes - exhaust?


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Just finished re-assembly and the car runs decent (considering I haven't rebuilt the Solex). Wouldn't idle at first but I removed the mixture screws and cleaned the gunk and shot carb cleaner in the ports and then it seemed OK. Now, it smells both in the cabin and all around the car. As usual, I am in learning mode. My guess is that it is running rich. Would that cause the terrible smell? I adjusted the screws per the instructions in the thread where I got the pic (thanks for that, it was very helpful) https://www.bmw2002faq.com/forums/topic/260208-solex-2bbl-post-rebuild-setup/?tab=comments#comment-1405270

I see only 3 adjustments. I turned the idle mixture in until it wanted to die then turned it back out too idle ok. Then I tried the Idle air control but that had no effect in or out. Then I adjusted the idle speed. Now the car seems to stay smooth at traffic lights. Are there any other adjustments? Still smelly.

 

I have read a few threads about fumes. There are quite a few regarding fuel fumes but I don't think that's my trouble. Pretty sure it is exhaust.. I tightened everything down pretty good when I reconnected the exhaust  (new gaskets of course).

This is a 1976 and I have all of the emissions stuff connected except for the round canister by the brake master cylinder. I see that it takes two vacuum lines, one of those goes into the left inner fender and I can't tell where the other goes. I don't see it on the emissions diagram sticker.  Next time I get a chance to work on the car, I might just try plugging the vacuums and try to isolate away the smog stuff. Can someone tell me where those vacuums go?

 

Also, I see that the hood seals could be an issue. I do have the side seals. The right side is still on but the left came off and I haven't put it back on. They are in poor shape, dried out and brittle. I see they are available for about 70 bucks the pair. I am considering spraying them down with A: undercoating  or B: PlastiDip in order to get them firmed up at least enough to see if they help (i would then order the seals if they don't hold up after my "restoration" (lol).

 

I did order a rebuild kit (part number 15646A) and even procured a used Solex and also a Weber (Thanks ScottA) but frankly, I was intimidated when I tried to do the rebuild on mine and that's when I tried just cleaning out the idle ports which got the car running better so I decided not to risk a rebuild. A local carb shop quoted me 250.00 for the rebuild but couldn't guarantee if there are bad parts they can't locate. That is about 50 bucks away from a new Weber from Ireland Engineering. I don't really have that budget unless it will really solve my problems (smelly, sometimes rough idle)...or I can attempt a rebuild on the weber. uuuugh....

 

 

 

2116962184_SolexCarb.jpg.d49e98e54c7fe9dc4e247a2532b6c812.jpg

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If it smells of exhaust under the hood you must have a leak somewhere inspect the whole system front to back looking for a crack or small hole it will probably have some black soot at the leak. If it smells of raw gas the first place to look is the fuel return line under the battery tray it should be plugged preferably at both ends.

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1 hour ago, MBar said:

).

This is a 1976 and I have all of the emissions stuff connected except for the round canister by the brake master cylinder. I see that it takes two vacuum lines, one of those goes into the left inner fender and I can't tell where the other goes. I

That sounds like the fuel system charcoal canister, designed to capture/store fuel vapors coming off the gas tank. One line comes from fuel tank and the other goes to carb inlet.

an open not connected line from fuel tank will cause a fuel smell.

lots of people including me have done away with it and simply routed  the line overboard.

 

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A bad trunk seal will allow fumes to be sucked into the cabin. Lots of threads on it.  I smelled like exhaust after driving my car for 15 minutes, especially with the windows open, ironically, since it creates more negative pressure in the cabin. I used house weatherstripping attached to the trunk lid to test out whether it was the trunk seal or not.

 

I also replaced the center hood seal that runs horizontally and attaches to the hood towards the back near-ish the windshield. Mine was super crusty. I also bought the side seals but haven’t installed those yet (best prices I found were at Walloth and Nesch) I put pieces of duct tape to make up the gap between the old crusty sode seals and the hood. Again, told myself this was “temporary” just to test out the hood and trunk seal but it honestly will be there for a while as I sort out mechanicals. The smell pretty much gone now. Side note, fumes are nothing to mess with. As much as I’d rather be buying sway bars and fancy steering wheels instead of seals, your health is really important and those fumes are toxic. It’s worth spending the time and/or money to fix it. 
 

You may also have a rich condition or a timing issue causing incomplete burn of the gas but that’s a different problem. 

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On 3/31/2021 at 9:46 AM, MBar said:

This is a 1976 and I have all of the emissions stuff connected except for the round canister by the brake master cylinder. I see that it takes two vacuum lines, one of those goes into the left inner fender and I can't tell where the other goes. I don't see it on the emissions diagram sticker.  Next time I get a chance to work on the car, I might just try plugging the vacuums and try to isolate away the smog stuff. Can someone tell me where those vacuums go?

 

The round canister is full of ancient activated carbon and often referred to as the charcoal canister.  The little line coming out of the firewall is the vent line from the fuel tank.  It gets connected to the canister and then another little line runs from there over to the air cleaner base.  It attaches to a little nipple that Ts off of the metal tube that the valve cover breather connects to.

 

Your photo shows that the fuel diverter valve has been removed.  Some people mistake that for emissions equipment.  If you still have that, I'd put it back in.  It allows the excess fuel pressure to bleed back to the tank when the engine is shut down.  Without it, the pressurized fuel can find its way into the intake, leading to fuel smells and possible flooding situations.

Tom

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