dropzone

iTrader: (6)

Took my '81 (22R, Miles could be 115K or 215K by the odometer, 5 digits) through DEQ (oregon emissions) Tuesday and This morning.
It failed for high Hydrocarbons both times. CO, CO2, CO+CO2 are all well with in range.


here is what I have for readings;
April 2007: HC 169, max is 220
April 2009: HC 65
April 19 2011: 1st test at idle (750 rpms) 639
2nd Test idle after a few minutes of 2500 rpms's HC 639

So I put on a new cap and rotor, adjusted the valves and put new gaskets inbetween the exhaust manifold and exhaust down pipe.

Today, April 20,2011
reading at idle (750 RPMS) 492
2nd idle test 510 (passing is 220)

Looks like the culprit could be the Catalytic Converter. Not even sure if there is an O2 sensor on these older trucks. There is what Toyota calls a Thermo probe at the rear of the Cat that is about 4" long.

Any advice would be appreciated...

85TurboRunner

Move up here to vancouver and you'll never have to worry about it again.

waskillywabbit

iTrader: (-1)

You said probe.

What's an emissions test?

Good luck with it.

:wabbit2:

crash121

Check needle and seat, float level, fuel pressure, choke setting, air filter and ignition timing. All possible causes of more gas than can be burned, aka high HC's

TheChewMaster

My old man has owned an 81 22r since 81. And he always has 2 cats. one for smogging and one for everyday driving. The stock cats just bolt in with three bolts really easy to change. reguarding the o2 sensor there is one, I forget where it is, I believe its on near the exhaust manifold, one wire, two bolts. has a metal gasket.

He always changed his air filters for smog test, and he's in cali

JustDSM

In my experience high HC's have been from it running leaner -- ie: vacuum leaks.

But that's not always the case with every vehicle. Wouldn't hurt to look them over though.

vital22re

iTrader: (2)

My 94 suburban failed hc at idle. Turns out my ignition was advanced 5 degrees. What's the other readings?

James Woods

iTrader: (1)

Do you mean emissions or the cat converter from the tweakers stealing it?

dropzone

iTrader: (6)

will check that.
new air filter.
I adjusted the lean mixture down between the two test, HC dropped from 639to 492
-Two bolts on each end of the cat.
-Will pull the heat shield to check the manifold for the O2 sensor

-Checked the vacuum lines everything 'appears' to be in good shape/routed properly
-I know Trekkerpaul's vacuum lines are routed correctly. will see about pulling it into his driveway and compare trucks side by side.

-will check the timing
-will post the other reading in the morning, don't have access to them right now.

My cat is pretty well beat. This cat from LC engineering seems to be the only one I can find with the provision for the thermal probe

the local parts stores around here all have cats that are 12.5" long...direct fit my big fat butt...

need to find a source for a thermal sensor.

Oh and moving somewhere with out emissions....in 4.5 years when my kids are out of school that might be an option. If I told them we were moving YT would need another mod and Waskillywabbit would be posting my obituary

dropzone

iTrader: (6)

Vital22RE:
here is the rest of the numbers:
April 19 2011: 1st test at idle (750 rpms) 639 HC, CO .3459, CO2 10.9
2nd Test idle after a few minutes of 2500 rpms's 639 HC, CO .3563, CO2 11

So I put on a new cap and rotor, adjusted the valves and put new gaskets in between the exhaust manifold and exhaust down pipe.

April 20,2011
reading at idle (750 RPMS) HC= 492, CO= .0478, CO2= 9.6
2nd idle test HC=510, CO= .0664, CO2=9.2

80banana

Check your cat converter. With the engine running, it should be much hotter than the temperature of the exhaust going into it. Do you have an infrared thermometer? That'd be the easiest way to tell.

Also, make sure your air control valve is working properly. Without a sufficient supply of air, the cat won't get hot enough to burn up the HC's.