High CO emissions, weber 36DCD

StefanLee · 05-30-2008

So my car failed the exhaust emissions test, again.

I did the test a month ago, and it registered a Carbon Monoxide level of 12 at idle. The problem was a vacuum leak in the brake booster increased the idle to over 2000 rpm, no good!

The leak seemed to be the problem, so I had the leak fixed before the test today. The 1900S engine idled nicely at 750 rpm, but still a CO level of 9 (the highest allowed level is 5,5 for my GT). The problem appears to be more complicated than a simple vacuum leak...

I have a Weber 36DCD on my car, and now I need to know how to adjust it to decrease the CO emissions...any tips on that? What else could be contributing to the problem?

Stefan

wrench459 · 05-30-2008

The carb is to fat.
CO is almost always a carb issue..high float level,sunken float,to high of fuel pressure,to large of jetting,and on and on.
Bet the nox numbers are low..and the HC's are high.
Could you post all of the numbers? It might help.

StefanLee · 06-01-2008

No, I don't have the other numbers as I only got a readout of the CO.

The car passed with the same carb and jetting two years ago. I'll try to lower the fuel pressure (I've been working a bit on the fuel system since the last test) and see if that helps. I have a local auto repairers shop pretty close that I hope can help me with a reading.

Stefan

bigjim5551212 · 06-17-2008

The DCD carb is a great unit. However, it has a couple weird things. Some of them have no vacuum advance. The fuel pressure can not be more than 3.5 psi either. Thats for any Weber. Check for throttle shaft play as well.

Now, the jets are not the same as the DGV. Only the main jets are the same. If you ever change the jets, pinch off the fuel line and run the engine till the carburetor empties. then you can take the jets out, otherwise you have gas running all over the place. We have some idle jets as well.

05-30-2008	#1 (permalink)
StefanLee Opeler Join Date: Nov 2006 Location: Sweden Posts: 220	Unanswered: High CO emissions, weber 36DCD So my car failed the exhaust emissions test, again. I did the test a month ago, and it registered a Carbon Monoxide level of 12 at idle. The problem was a vacuum leak in the brake booster increased the idle to over 2000 rpm, no good! The leak seemed to be the problem, so I had the leak fixed before the test today. The 1900S engine idled nicely at 750 rpm, but still a CO level of 9 (the highest allowed level is 5,5 for my GT). The problem appears to be more complicated than a simple vacuum leak... I have a Weber 36DCD on my car, and now I need to know how to adjust it to decrease the CO emissions...any tips on that? What else could be contributing to the problem? Stefan

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

06-01-2008	#3 (permalink)
StefanLee Opeler Join Date: Nov 2006 Location: Sweden Posts: 220	No, I don't have the other numbers as I only got a readout of the CO. The car passed with the same carb and jetting two years ago. I'll try to lower the fuel pressure (I've been working a bit on the fuel system since the last test) and see if that helps. I have a local auto repairers shop pretty close that I hope can help me with a reading. Stefan

06-17-2008	#4 (permalink)
bigjim5551212 Weber Carburetor Guru Join Date: Jan 2008 Location: Vancouver Canada Posts: 129 Provided Answers: 1	The DCD carb is a great unit. However, it has a couple weird things. Some of them have no vacuum advance. The fuel pressure can not be more than 3.5 psi either. Thats for any Weber. Check for throttle shaft play as well. Now, the jets are not the same as the DGV. Only the main jets are the same. If you ever change the jets, pinch off the fuel line and run the engine till the carburetor empties. then you can take the jets out, otherwise you have gas running all over the place. We have some idle jets as well.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)