Tune Up Question

[Jon]

After tuning up the 2002, the plugs are picking up black carbon.

The Weber 32/36 is tuned slightly lean.
If I go leaner, it starts to stall.
The timing is 1 to 2 degrees advanced.
Points, condenser, plugs are new.

Can anyone tell me why the plugs are picking up carbon?

[Jon]

No one tunes up their 2002 anymore?

[Arizona 02]

Remove the top of carb & take out the 2 main jets and write down the # and tell us. I think the primary any should be less than 145.

[Jon]

Good point about the idle adjustment: most of my driving is back roads, so the carbon is building up at speed. I will check the jets.

The timing had been a few degrees retarded, and then I set it a few degrees advanced to give better acceleration. Could that be the problem?

[Arizona 02]

[2o=00=o2]

Are you using the same heat range spark plugs as before the tune up? Colder heat range plugs will do that? Is the soot on the outer ring of the plug where the ground electrode is attached. Do you have a manual or electric choke system on the Weber? Sticky float? What kind of air filter are you using, have seen over oiled (K&N, foam, etc.,) filters cause rich running, sooted plugs. You have a rich running (stuck choke, restrictive air filter, sticky float or float valve) or cold combustion temp (plug heat range, resistor plugs, coil going bad, I reaching here so don't flame me LOL). I had the exact opposite happen by just putting in a set of hotter plugs, I failed an E-check with high NOX (byproduct of high combustion temp) and just change back to the stock heat range and passed the E-check the next day, who would have thought? Advancing the ignition timing usually makes a little hotter combustion temp.....at least I always thought it did?

Not enough air, too much fuel or too cool combustion temp (plug heat range) good luck..

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[jonblbl]

The 32/36 is rebuilt.
Wiring, points, condenser, cap, rotor, air cleaner are all new.
Electric choke is set properly
The COIL is NOT NEW; may be original.
Timing is slightly advanced.
WR7DC and WR8DC pick up carbon. (With the old carb, hotter WR9DC's
did not carbon up.)

My options are: new coil, hotter plug and/or change the timing (more advance?). What would you do?

[2o=00=o2]

Jon, "All of the above". I'd hold off on the coil and do the hotter plugs and a little more advance first. The new coil is a good idea but hopefully the one you have is still okay? I've had a Bosch "Blue" coil on one of my 02's for sometime with no problems, if you have a stock coil you might want to try the blue coil or if someone has a better option I might try something new too.


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[badcabbage02]

Fundamental question: how old or how many miles on that Weber? It is a Weber?

I speak from experience. I had a 32/36 that had well over 50K miles on it, and I simply could not get the engine tuned properly - I kept having to up the mixture to run properly - result - fowled plugs.

What I was doing was upping the fuel mixture to compensate for more air flow, but could figure out how that could happen.

Turns out I was getting air leaking around the brass or steel shaft for the throttle plates in the carb. They sit in a softer cast metal in the carb housing and over time, due to mild vibration and motion they loosen within the body of the carb. REAL PAIN.

Some say you can shim the housing, I opted for a new Weber.

Solex carbs didn't do this. People complained about Solex because they were tough to tune, but all in all they are a better carb.

Food for thought...

James L.

76 2002
72 2002 automatic
91 318is
75 TR6

[2o=00=o2]

Good point James, and with that it brings up the question; were the former plugs that were in it "sooted" when they were pulled out for the tune up? If they were then I would suspect the carb is worn as James pointed out. Jon, back to you with "What is it?"

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