Gordie

I've been having trouble passing the emission test (hydrocarbons) with my 91' 100. I've changed plugs, air filter, run injector cleaned through the gas, but not even close. Is there a way to adjust the air-fuel mixture??? Also, could a bad crankcase breather hose add to this problem???? Mine is soft and gummy.
Thanks

alpinab7

if CO is normal and HC is high it is unburned fuel: probably a misfire. Cap, rotor, wires? I wouldn't adjust the A/F unless you can determine that is the problem for sure.

alpinab7

rich A/f ratio would have high CO as well, try O2 sensor too

4Driver4

Dirty oil will cause high HC at idle. Change the breather hose too.

Gordie

Then it probably is not the A/F mixture since the CO is low and the O2 sensor is only about 1 1/2 yrs. old. I'll try new cap and rotor.
Thanks,

Gordie

The oil was just changed, but the breather hose is indeed bad.

5000CDQturbo

make sure the car is warm to hot before they test it ... the catalytic converter needs to be hot to work corectly

Gordie

The cat is original, the car was definately warm.

5000CDQturbo

I know you have done some of these, but I did a search on testing tricks.
>Oil Change
>Filter Change
>Hi-test (91+ octane) for at least a week--NON-Leaded (if they still sell the leaded beast in Canada).

>If it's fuel injected, get a product called Lucas Tune up in a Bottle. It's the best gas treatment around. That will help immensely.

>Emissions pass fluid, new O2 sensor, new plugs wires, coils, catalytic converter, all no dice.

>You may have a partially plugged exhaust passage that feeds the EGR valve

>Check the ignition timing. If it is too far advanced, it will raise the NOx. If the timing is okay, check the operation of the EGR valve. If it is okay, you may have to replace the catalytic converter.

> Check for a flat camshaft. If okay, perform a cylinder leak down test, which will pinpoint which valve is causing the problems. You may have to remove the cylinder head to correct this.

> If the engine that you have in your van has the 200,000 miles that you indicated, there is a good chance that the engine is worn out to the point that the blow-by will contaminate the exhaust, causing high hydrocarbon readings. We would recommend a motor overhaul to our customers in this situation.

&gt;en<ul><li><a href="http://www.2carpros.com/topics/smog.htm">http://www.2carpros.com/topics/smog.htm</a</li></ul>

SteveAngry

How old is your 02 sensor? Cat?

Steve
Michigan