@%$^ing Aircare

[ghiaholic]

Failed Aircare for 3rd time.  Looking for any suggestions.

VIN: 1402012717     http://www.aircare.ca/index.php?inspinfo-g...get-results.php

Motor:  1776, unknown cam (think it's stock or mild), stock heads, stock exhaust, brand new 009 timed at 32 degrees full advance, new wires, new plugs, new coil, good compression readings, running Ethanol blend gas, fresh oil change.

First trip through 06/05/13 running Kadrons tuned as best as possible it failed idle HC's brutally.  Motor ran strong but it was no surprise with those carbs.  

So, out came the motor.  After a teardown, the heads were removed, inspected, reinstalled and retorqued.  Valves set at .006.  Motor reinstalled.

Second trip through 06/06/03, ditched the Kadrons, running brand new Pierburg 34 PICT 3 and brand new Bruck SVDA.  Timing set at 5 degrees BTDC.  Idle set to 850.  Idle mix set to the point just where the idle starts to drop.  Basically the stock setup running real nice.  Should pass right?  Wrong.  Failed Idle CO.

Third trip through 06/06/03, everything the same except I swapped the Bruck SVDA for the 009 (because this is the setup that was used the last time I passed 2 years ago).  Timing set at 32 degrees max advance, idle set to 1000 rpm and mixture again set to where the idle just begins to drop.  Running great and making smooth power.  Should pass right?  Wrong.  Failed idle HC's.  

WTF is going on?  I know I can pay someone with an EGA to test it but I'm not going to let the man beat me.  Should I retard the timing a few degrees to get the HC's down?  Does a change in the timing affect the CO reading?  Is the problem the 1776 with the small carb?  Do I need to move to a postal code where I don't have to put up with this crap?  I'm at an absolute loss.  Aircare is about as useful as the gun registry - a simple ineffective political solution to a complex problem (but I digress).

Anyone out there that can shed some light on this?  What am I missing??
 

[BUSDADDY]

Timing changes won't effect co but make a big difference in hc.  Hc's are caused by a sick motor or incomplete combustion, you need to advance the timing to allow more of the bad stuff to burn off. A miss caused by too lean a mixture can also add to the hc levels (probably the case in your third test). Notice your second test, although the idle was too rich the hc was acceptable.  I would go with the SVDA and set your co to 3.5% (really should be done with a meter as 1/4 turn on some carbs changes co 3% or more). With your engine configuration and good compression it should not be hard to pass but remember what aircare likes and what runs nice are two different things, they sure give me funny looks when I get out and re adjust the carb and timing before I leave the lot.

[Bruce]

I agree, you must go back to the vacuum dist.

In your second test at 1:33 on Sat, you simply had the idle mixture set too rich.  Leaning it from there would have gotten you through.  Time the vacuum dist the way you had it during this test.

You have another problem.  Your idle jet is too small.  0.13% and 0.14% CO is too lean and could cause a lean misfire (although you didn't have one during the test)  Take it out and get the next size bigger.

[ghiaholic]

Good call on the idle jet being too small!!

The Pierburg is supposed to be shipped with a 55 idle jet.  This should be plenty big even for the 1776 and I never considered that it would be part of the problem.  So for shits and giggles, I pulled the idle jet out.  It has no size stamping on it at all.  Sure enough the drillings looked too small, so I pulled the idle jet out of an old original 34 PICT carb to compare.

Check this out   http://vw.quiringjellis.com

If you look closely, not only are the drillings too small, they appear to have been crushed.  The jet on the right is the original Solex 55 idle jet.  If you look at the end shot, you can see how much smaller the Pierburg drilling is.  CAVEAT EMPTOR - if you're buying a Pierburg, keep the jets from your old carb!!  

I'll try to run it through Aircare again tomorrow with a real 55 idle jet and the SVDA reinstalled.   Wish me luck.  I'll post the results.

[captCRUNCH]

you could also buy/borrow a msd if you fail. i ran my 1641 with kads before and after i installed my msd and noticed a big change in numbers (in a good way). i'm far from an air care pro but its worth a shot. good luck man...i know what you mean by a messed up system...i used to work there      

[vwguy29]

For aircare u really need to use a gas analyzer to set everything up to pass rather than guessing

[Bruce]

For aircare u really need to use a gas analyzer to set everything up to pass rather than guessing

Stock engines are much more forgiving when it comes to Aircare.  Plus, if you follow VW's instructions to the letter, you are bound to pass with ease.  It is true that an EGA is a great tool, but to get a stock engine through, you don't have to use one.
 

[ghiaholic]

FINALLY!!!  4th time through it passed, but barely.

Running the stock setup with 34PICT, 55 idle jet, unknown main jet, SVDA timed at 7.5 degrees BTDC.

I set the idle to 1100 rpm, and opened the thottle butterfly just slightly more than you're supposed to (just before the vacuum kicks in) to try to get it off the idle circuit a bit.

Moral of this thread - don't assume anything.  I assumed that the BRAND NEW carb and BRAND NEW distributor would work out of the box.  WRONG.

Big thanks to Bruce and Busdaddy for the suggestions.

Peace out.

[BUSDADDY]

Good news !!

Barely is fine as long as it passed. Now write down everything you did somwhere so you can pull it off again next year.

[Bruce]

Driving HC -- Driving CO -- Driving NOx -- Idle HC -- Idle CO
 86 ppm ------- 0.09 % ------ 782 ppm  --- 942 ppm -- 5.14 %  


I don't think you are done yet.  0.09% CO driving is way too lean.  It is almost as if you put a smaller idle jet in it than it had with the crushed idle jet.  I think you should take it back out and compare it again.  Also, try to measure the size.  Thesize of the holes in the side don't really matter, it is the one in the center at the end.  Leaving it the way it is will make it run hotter than it should.

Once you get that sorted out, you will be able to set the idle mixture properly.  5% is too rich.  That is what is partly causing the HC to be so high.

You won't need to set the idle speed at 1100 to pass then.  It will be so far below the limits that you will pass every year without messing with any settings.

Check out the results on this stock engine in a 72 Super:  1122019461  

http://www.aircare.ca/index.php?inspinfo-g...get-results.php

The engine was never adjusted to get through aircare.  No methanol in the tank, half the time I wouldn't even change the oil ahead of time.

[ghiaholic]

Bruce:

I think I need to change the title of this thread to #$%in Pierburg carburetor.  Here's what I found.

You're right that it is WAY too lean.  So while fiddling with the carb settings, I cracked open the idle jet while the car was running and wouldn't you know it, the RPMs increased and the idle smoothed out.  I guessed that the problem may be that the 4 drillings around the side of the idle jet weren't matching up with the circuit that had been drilled in the carb.  This shouldn't really happen, but with this carb anything is possible.  So I filed a groove between the 4 holes going around the idle jet.  Here's a picture of what I did:  http://vw.quiringjellis.com  (scroll down to the 3rd picture).  I also took a stick pin from the wife's sewing basket and cleaned some gum out of the hole in the end of the jet.

While I was at it I pulled the top off the carb and pulled out the main jet.  Apparently these are shipped with a 127 main but none of the jets on these carbs are stamped with a size so who knows what it is.  I happened to have an original 130 Solex jet on hand so I swapped that in and replaced the emulsion tube with an original while I had the carb top off.

To make a long story short, the modification to the idle jet fixed the problem of having to crack open the jet to maximize the idle.  Also, the slight misfire has almost completely disappeared.

So your comment about it seeming that I put in a smaller jet actually referred to the lean condition caused by the idle jet holes not lining up with the idle circuit holes drilled in the carb body.  It even smells different when it's running now - I can smell the richer burn.

IMHO, I wouldn't buy another Pierburg.  They're prettier than the Brosol's but that beauty's only skin deep.  I bought a Brosol 34 Pict 3 from Airspeed last year and it has run flawlessly for me in my bus (other than the cutoff solenoid packing it in within a month).  Given the choice, I'd recommend the ugly Brosol over the Pierburg.

Sincerest thanks for all the help.  

 

[captCRUNCH]

too bad you changed your settings...you could of gone in for another pass 5 days later and you would have been good for next year when you go to renew.  

[ghiaholic]

OK, it's been a year since I started this thread and today I took the car through AirCare for her '08 test.  The '08 numbers are quite a bit better than the '07 numbers (the VIN is in the original posting in this thread).  The ONLY change between the 2 tests is the hole in the end of the idle jet.  I re-read Bruce's comment that the idle might be too lean.  So without a proper set of jet drills, I McGyvered a solution to increase the size of the idle jet.  I found that a sewing needle wouldn't quite fit into the hole in the end of the jet, but it was close.  So I put the needle in a set of pliers and worked it into the hole until it was a friction fit.  This is NOT a recommended procedure by the way - just what I did.  After reinstalling the jet, the motor ran the best it's ever run.  The dipstick is only warm even after a 20 minute romp on Hwy #1.  So now I was scared to take it through Aircare because it was running too good!!!  Well, the numbers don't lie.  The driving CO is higher, but I think that's because he did the driving test in 3rd gear so he was still partially on the idle circuit.  Now we just need some F$#&*ing SUNSHINE so I can drive it!!!!!!!!!!!

[Bruce]

It looks to me that you opened up the idle jet sometime between the '06 and the '07 test where the driving CO changed from .09% tp 3.11%.  Is this correct?

Your idle CO is now too rich.  This is very easy for you to fix.  Just turn in the mixture screw until you find the point where the idle speed drops off.  Then back it out until the idle speed picks back up.  Do not turn it out further from this point.  You will notice the engine will run better, and your mileage should improve.

I recommend you always hop over to the passenger seat for the test.  Then when the moron puts it in 3rd gear, you can instruct them to use 2nd.  According to Aircare head office, the test MUST be done in 2nd gear.  I don't know why these idiots insist on doing what they know is wrong.  When it is done in 3rd gear, the engine is lugging.  This makes it run hotter.  Hotter means it will run richer.