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Carb experts on holley 5220 failed e-test.
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Author:  Wizard [ Tue Jul 25, 2006 10:09 pm ]
Post subject:  Carb experts on holley 5220 failed e-test.
This is in early 1987 plymouth voyager (canadian). I tried other two forums and wasn't satisfied with their replies.

Here's the text:

Plymouth Voyager 1987 carbed 2.2 (early year).

Tulip was taken in for E-test, drove 25 minutes to get engine good and hot, past few days I drove total of about 58KM for past few days.

Idle:

HC 232 (limit 300) pass
CO 2.16 (limit 1.5) fail
NOX n/a
RPM 888 valid
Dilution 12.15 valid

40KM/H:

HC 101 (limit 105) pass
CO 1.06 (limit 0.75) fail
NOX 1375 (limit 1192) fail
RPM 1979 valid
Dilution 12.33 valid

Carb is 5220, 2.2L, rebuilt 2 years ago.
Air pump is working
Coolant is good, new thermostat.
Oil still fresh and amber-clear.
EGR is working and new.
Catalyst converter NOT replaced YET.
PCV replaced and freely breathing.
Compression ratio I took in 2004 was around 165 for all cylinders, if I crank too many turns, can pump up to 180 PSI.
Head is not "correct" for carb (using fastburn head 782 in Tulip's) and dated 1989, I did not replace head BTW. The 2.2 carb uses bathtub head (287).

History: Carb was ruined and messed with to run rich because of manifolds leaking and vacuum leaks. All fixed prior to E-test.

Where mechanic might be pulling my leg is during e-test says had blue smoke during 40KM/h test section. We tried ourselves and did not get
any of this.

What make me wondering why the CO and NOX is failed. Google showed
that if CO is caused by rich (should be burning cooler but it is opposite, lean causes NOX. What?) The two thing I could think of is catalyst converter and redo the carb rebuild, the mixture set up (jets and idle mixture screw) is the hard part that I would have to do.

Cheers, Wizard
Author:  Reed [ Tue Jul 25, 2006 10:27 pm ]
Post subject: 
A carb running too rich can foul the catalytic converter and make it not function properly. I recommend replacing the catalytic converter and the O2 sensor. This should be lesst than $150 in parts.

Your carb is clearly running too rich at idle. This suggests your curb idle mixture is too rich and/or the O2 sensor is faulty.

The NOX is most likely caused by a fouled catalytic.

Good luck!
Author:  Wizard [ Wed Jul 26, 2006 6:18 am ]
Post subject:  Richness.
Sure the carb is fine at cruise because the CO is bit high?

The NOX is still high, how much of this to drop when catalyst converter
is replaced?

Cheers, Wizard
Author:  SlantSixDan [ Wed Jul 26, 2006 6:56 am ]
Post subject: 
I agree that the catalytic converter is suspect #1 in this situation. At 40 km/h, you're barely passing HC (just 4ppm under the limit), you're flunking CO and NOx. The common factor amongst all those pollutants is the catalyst; if we disregard the catalyst, then you're looking at opposite causes for high NOx (too lean) and high HC/CO (too rich).

Other things to look at:

•The carb may not be adjusted properly and/or there may be vacuum leaks -- these particular 5220s aren't anywhere near as bad as the Japanese carbs used on the 2.6s, but they still have their share of tricks up their sleeve. You say this carb was "ruined and messed with" but that this was fixed. How was it fixed?

•Spark plugs. Don't know how old they are. Try out my favourite NGK ZFR5N plugs, which have an extended nose that tends to give more complete combustion. I've used them with good success in 2.2/2.5 cars. Also pay attention to the rest of the ignition system (cap/rotor, wires).

•Ignition timing. Make sure it's set exactly to spec; it seems to have a larger effect on emissions on the 2.2/2.5 than on some other engines.

•Air filter and entire PCV system (valve already replaced, check hoses/elbows/grommets, and the crankcase inlet air filter mesh in the air cleaner housing)

•You mention the EGR is new and working. Does that mean the valve, or did you also check and clean/replace the crossover pipe? These tend to get clogged up with carbon, and you can have a perfectly working valve that doesn't actually let any exhaust into the intake manifold because the tube is clogged. If you apply vacuum to the valve with the engine running, does it drop speed and try to stall?

I think the mech might be fishing for dollars with the blue-smoke comment. The vans that tend to smoke are the ones with the 3.0 V6. You might try a different mech for the next test.
Author:  Wizard [ Wed Jul 26, 2006 7:28 am ]
Post subject: 
Carb was junk from the damage (small piece of plug sawed off to get at 2 tiny pinholes then PLUGGED with RTV). :shock: And what more secondary throttle was RTV'ed too!

http://www3.sympatico.ca/jpero/misc/glued_secondary.jpg
http://www3.sympatico.ca/jpero/misc/sawn_off.jpg

So I had to get another 5220 (off the different car I think OMNI or another carbed 2.2L) and moved the jets from old carb to "new" with jets in correct place observed during rebuild. Main jets was swapped around to richen up in attempt to cover the manifold & vacuum leaks. (Fixed).

The main (fuel) jets is smaller for primary with air jet larger of two, main for the secondary is larger and got smaller air jet size.

Yes, I'll recheck the ingition timing and get another coolant sensor, this new coolant sensor was third party part, Niehoff. The timing belt is installed correctly. FOR SURE but can't hurt to recheck (trivial).

Once again, is there someone with 2.2 caravan or have a 5220 carb off the caravan, please report back with jets and mixing tubes numbers, ESA (spark control computer) part numbers? Because mine is different part number and are not sure which is correct.

Cheers, Wizard
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