replaced cat, full tuneup,seafoam, n still failed smog! High HC

[Friend Of P]

Hi, guys!

I'm running out of ideas and money.

mine is a 88 camry, manual transmission, non cali model. 193xxx miles.

When i first took the car to get smogged (cali standards) I did the following:

replaced: spark plugs.
cleaned the EGR valve.
seafoamed the crankcase, fuel and vacuum.

adjusted timing to 12 deg.


Readings:
HC
15mph
max: 121
mine: 227

25mph
max: 96
mine: 123

CO:
15mph:
max: .76
Mine: .57

25mph
max: .65
mine: .04

NOX
15 MPH
max: 807
mine: 1261
25MPH
max: 746
mine: 1171

FAILED.

after that, I
installed: spark plug wires, Toyota air filter, bosch oxygen sensor
recleaned: the EGR Valve and the metal pipe leading to it.
New Catalytic converter installed.

The 2nd time getting tested:

CO:
15mph:
max: .76
mine: .55
25 MPH
max:.65
mine: .60

NO:
15MPh
max : 807
mine: 339

25 MPH
max:746
mine: 44 (yes, 44) Previously it measured 1171

However,
HC:
15MPH
max: 121
mine: 258

25 MPH
max: 96
mine: 261

FAILED.


at both speeds the HC went up! Shouldn't they have decreased cause of the new cat? did i get a bad cat?

so, now, i'm out of ideas.
I was told a reason might be:
since the oxygen sensor is being held on by 1 nut and 1 stud, oxygen is coming in and throwing off the readings. the other stud broke flush.

was also told at last oil change that oil pan is leaking (but it was also leaking 2 years ago and it passed!) . might oxygen be coming in thru there?

the idle is a bit erratic after the engine has been running for at least 20 mins...but before that, it is quiet.

Help!

Thanks in Advance

[toyomoho]

The CAT lowered the N0x values.

High HC is unburned fuel. If the engine is missing this could be the problem.

Make sure the EGR system is working It should be off at idle but working at speeds.
Intake manifold leaks.
Ign problems such as low ign spark or incorrect ign timing.
Burned valve.

If the area around the O2 sensor is leaking this can throw off the sensor reading and result in the wrong air fuel mixture.

[Doctor J]

What are the O2 and CO2 readings?
I can speculate that the engine is probably running in the open loop; verify that the system is in closed loop and get fuel trim value.[in closed loop CO must be about 0.15%, not 0.50%
I recently answered the pm regarding HC failure at low speed during two speed idle test.{92 camry V6} Turned out that bad exhaust valve seals let the oil leak into the exhaust ports aka post combustion leak; at high idle the cat was hot so it burned the oil, but at low speed the car failed . ALL other readings were ideal. after changing the oil to 20W50 and cleaning the PCV valve the car passed.
Let me know if you need more info about feedback test and fuel trim reading.

[Friend Of P]

for the first test the readings were the following:

15MPH
CO2 %: 12.5
O2%: 2.4

25MPH
CO2: 13.5
O2: 1.6


the second test:
15mph
CO2: 13.8
O2: 0.8

25MPH
CO2: 13.8
O2:0.7

How would I do the verification of open/closed loop?

[metrodriver]

Get a can (actually 2 or 3) of the stuff that guarantees you will pass the emission test, and it is called Guaranteed To Pass, made by CRC, the folks at the autoparts store will guide you. It cleans the fuel injection system and the combustion chamber. I needed 2 applications of the stuff before my car (same engine, year and mileage) passed. You drive the tank empty, poor a can of the stuff in it and then fill it up with fuel. Repeat this process a few times. The performance of my car improved dramatically. Eventhough I changed plugs, wires, oil after it failed the first time, it still failed. After 2 bottle of G2P, it passed with flying colors.

It is the cheapest fix at about $8.- a bottle

[Doctor J]

The first two tests are indicating slight missfire [some extra oxygen]; during the second test it is less.
The empirical formula for combustion efficiency 14%=CO2+CO+O2 [used for the cars without air injection aka pulse air or smog pump]
to do the test: warm up the engine so until the colling fan comes on, then attach analog voltmeter set at DC volts 0 to 10 v range: red probe to Vf terminal in the diagnostic box, black probe to E1; jump T and E1 terminals.
Increase the engine speed to 2500 rpm and hold it there.
Observe volmeter
the needle should sweep across the 0 to 5 v range 8 times per 10 second period, if it does the engine is in the closed loop and mechanical problem is indicated.
With new cat, even the "missing" spark plug will be "covered up" by a cat.
Make sure you set timing at 10 degrees BTDC
to check the fuel trim, at engine idling attach the digital voltmeter same way as above, but without jumping T and E1 . read the scale with engine idling at low speed if it reads 5 v the comp is adding more gas compensating for lean , if it reads 0 the comp is compensating for rich condition. If the engine has leaking exhaust valves, it most likely will read 3.7 [like on my car].
FYI: if the car fails as test only the state could pay the shop $400 to fix the car and you pay $100 [if you are low income you pay $20]