HIGH hydrocarbons

[marcandfiveonettes]

Hey there. I just barely passed my emissions test. I failed by 6ppm the first time, then changed my spark plugs, went back and passed by 2....

any advice on other ways to get my hydrocarbons down? It smells terrible.

[dlb]

there are a few threads on this so try searching. i know there were a few guys who posted their entire smog saga on here and there was tons of info on what they did to reduce particular pollutants.

personally, i would just use the FSM and test each emission system. if the system passes, you move on to the next one. if it fails, you can test each component of that particular system until you find the guilty party. all the tests are really simple, and you'll likely find a few things to fix. old TVSVs are prone to wearing out so they don't often function properly on the highest heat stage, and that can cause several problems. forum member 4doorVIP has a few brand new TVSVs though so you might be able to get one from him. anyway, search for those threads and/or use the FSM to inspect each emission system. good luck.

[dlb]

just found the thread i was thinking of. it's a long one. starts on the second page so maybe read through from there.

https://tercel4wd.com/forums/viewtopic.php?f=4& ... =15#p54294

[Petros]

high hydrocarbons means it is not burning efficiently, and there are unburnt fuel in the exhaust stream. this can come from too things: either too rich, which is not likely since there would have been other likely out of range as well. Or too lean, believe it or not, too lean a mixture can causes it to have unburned fuel in the exhaust. When lean you have a weak, low temperature combustion you get incomplete burning. Lean likely means a vacuum leak somewhere, likely not a bad one. check all the vac lines for cracks or breaks, verify they are routed correctly, etc. check for gasket leaks under the carb, at the intake manifold where it bolts to the head (these often work loose), EGR, and vac advance for leaks, even a cracked TVSV could cause a vac leak.

you also might have a weak spark, check the condition of the wires and the contacts inside the cap.

good luck

[john]

I had hydrocarbon readings that were among the worst the smog shop had seen. With the help of tercel4wd.com I was able to get the HC's down to almost nothing. I do not know how to make a link, but it was posted on this site:

john » Thu Oct 20, 2011 8:39 pm
2 normal spark plugs and 2 carbon fouled

Lots of ideas on lowering emissions can be found there.
best of luck, john

[dlb]

here's the thread john's talking about:

https://tercel4wd.com/forums/viewtopic.php?f=4&t=7016

[tercel4wdrules]

If you post the emissions gas readings here, we can try and help you to try and find what's causing the high HC output.