FAILED Emissions!

What was your CO reading? How about NOX, are they testing that too?

It has been my experience that high CO is a result of carburetor/FI malfunction(too much fuel or not enough air). High HC is usually ignition related(timing, plugs, dwell, and so on) or indicative of a failed catalytic converter. High NOX means your EGR is not working or your timing is REALLY off.

Post the other numbers and maybe something will become more obvious.

300 is about what the threshhold is out here in the southwest if memory serves me right, so I suspect you should be able to meet that spec even if your cat was not functional.

Chris

Way back when your '77 FI Bug was new (and for many years afterward) VW dealers had equipment to diagnose the workings of the FI system. They would plug their equipment into the engine's electronic control unit, commonly called the ECU or black box; a printed readout was the result. My VW repair manual published by Bentley says "testing with other equipment may produce inaccurate or inconclusive results and can permanently damage the control unit."

It's not likely that any dealer still has that testing equipment which was of Bosch or VW origin. There is always a chance that a garage specializing in aircooled VW repair has the testing equipment or are experienced in repairing FI problems.

You don't want to replace parts hoping that any change will improve the HC reading. You may have just one failed part, such as an oxygen sensor, and a mechanic experienced in FI repair should be able to find out what's wrong.

Take a look at some of these websites: Although the following website is California specific, there is a lot of useful information on it particularly topics 9-15 and 21. For more help from VW owners, ask your questions on one of the Samba forums.

-- Randall

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You can check the fuel mixture (CO) by measuring the output voltage of the O2 sensor with a multimeter/voltmeter capable of displaying millivolts. (0-1V range). I don't know what the limits are for where you are, but for a good running engine you would want to see the O2 voltage between 500 and 800 millivolts.

Here's a chart for voltage vs. mixture

Older cars like our VW's like to run richer than newer cars. For emissions purposes, you probably need to lean it out from where it makes maximum power, to where it makes minimum emissions. Then after you pass, adjust it back :D

HC is unburned fuel, time for a tuneup.

So what your saying is that my EGR shouldn't be disconnected.

I had disconnected a few years ago, so it could be the culprit

First find a shop that has the equipment to test CO/HC/NOX. Does your exhaust have a catalytic converter? Does your FI system even have an Oxygen Sensor? The dealers had a large computer to plug into the Beetles but AFAIK they rarely used them and I don't think it was sophisticated to read CO nor HC. I believe it was a cute idea but only told the tech general information about charging system, ign system, battery, etc. I could be wrong though and Speedy Jim would know more! :-(

HC should be reduced by tuning up the ignition system, keeping the ign timing retarded, and adjusting the fuel mixture. Fuel mixture will affect HC and if you go too lean the HC will rise. Fuel injector spray pattern and built-up carbon deposits inside of the engine will affect HC. Maybe if a good fuel system cleaner is used it could clean things out. SeaFoam or BG44 and some have tried using 100% Acetone. I can't find BG44 locally and I am afraid to use Acetone, so I sometimes use SeaFoam and will try Lucas too since it is relatively inexpensive in a concentrated bottle. ;-)

YES post ALL of the results, both idle readings and fast speed readings. I will assume that they are "driving" while testing? EGR valve is usually not-functional at idle and will probably not affect HC then!

Tune up......new plugs, wires, cap, rotor, adjust valves, change oil and air filter, etc. Which Spark Plugs are you using? How strong is the ignition spark at the plugs? What are you setting the timing at and does the advance work? Single or Dual vacuum advance?

A little light reading.......

JMHO

Here's the readings:

HC 1675 CO% 0.39 CO% 9.2

NOx were not measured.

RPM 1090

All emission control devices must be 100% operational to limit emissions, that is why they are there!! EGR = Exhaust Gas Recycling.

J.

The VW plug in tester really only tested basic parameters. The most interesting one though was compression ratio. As far as I can work out it did it by measuring the starter current ( by measuring the voltage across the cable from batt to starter when starting) and differentiating it. As the starter came up on the compression stroke the starter current increased more rapidly on a high compression than a low. On my cars it gave an indication rather than absolute figures. Everthing else was readily checkable, even to an amateur like me. The Fuel Injection tester you could duplicate with a good multimeter , specially if you had Elfrinks book. John

Not sure if those are the correct readings but it the CO is actually 0.39 then it is too low and it is possibly adding to the HC. Could there be a vacuum leak too? Check ALL vacuum hoses and the gasket on the oil cap.

What is the initial ign timing (idle) set at? Dual or Single vacuum advance on that distributor?

Here is a link for aircooled VW F.I.:

I hope it helps.

Here is a link for aircooled VW F.I.:

I hope it helps.

The state of NJ seriously expects a 33-year old car to pass emissions?? Not even California does that!

Ken

At least there is one good thing about CA. I don't have to do anything except pay the registration fee.

Eddie