Gross Polluter help (1 Viewer)

[Terry Lindsey]

Hi guys, it’s me AGAIN... in short, my smog check failed for high HC at idle (see pic). Prior to test I did a major tuneup consisting of carb rebuild, points, plugs, rotor, cap, vacuum lines and timing. I just did a compression test and the results are as follows: #1-120, #2-125, #3-110, #4-125, #5-118, 6-118.
I’ve readjusted (lowered) the idle mixture and set idle at just below 800 (will not idle any lower). Oh, did I mention that I had to buy and install ALL of the smog equipment as it had none? Any ideas on how to lower the HC at idle? I’m going to recheck my valve adjustment to see if that has any impact on #3 compression. Thanks

 

[Terry Lindsey]

Oh by the way, it’s an early 76 FJ40 in Calif

 

[spotcruiser]

Search emissions or smog testing here on mud. There is a list of things that people have found to help, such as using "Heat" fuel dryer in the tank.

Adding a catalytic converter might help. I wonder if they'd pitch a fit over a flanged-in section of exhaust with a cat. Hey, you're just trying to be a good citizen, right?

Did you end up having to install a cooling fan as mentioned in a previous thread?

 

[spotcruiser]

Here's a couple of threads I found by searching for smog and Heat and high hc.

HOW TO: Pass CA Smog test easy!

Off the charts HC - California Smog Fail

 

[Terry Lindsey]

Search emissions or smog testing here on mud. There is a list of things that people have found to help, such as using "Heat" fuel dryer in the tank.

Adding a catalytic converter might help. I wonder if they'd pitch a fit over a flanged-in section of exhaust with a cat. Hey, you're just trying to be a good citizen, right?

Did you end up having to install a cooling fan as mentioned in a previous thread?

No cooling fan needed apparently

 

[spotcruiser]

Cool. I added another old thread that looks helpful to post #4.

No cooling fan needed apparently

 

[pjohnson]

What year is your vehicle? Nm, just saw it.

Here's another site...
What Causes High Hydrocarbon (HC)? | SmogTips.com

Vacuum leaks?
Timing correct?
Points set properly?
Plugs gapped correctly?
EGR closed? fixed

Your numbers would indicate there's multiple problems.

 

[Terry Lindsey]

Thanks, the HC is only high at idle and I’m not sure how to check the EGR

 

[spotcruiser]

The EGR valve should be closed at idle. Open EGR at idle will cause the engine to run rough and stumble.

 

[pjohnson]

Idle circuit in the carb dumping too much fuel?
Maybe consult one of the carb gurus?
@FJ40Jim
@65swb45
@Pin_Head

 

[David70FJ40]

CA checks smog on a 41 year old truck?

 

[pjohnson]

CA checks smog on a 41 year old truck?

1976 and newer vehicles are required to pass a full visual and sniff test every 2 years.

 

[1969FJ]

Usually it is vacuum leaks .

 

[SW20]

CA checks smog on a 41 year old truck?

California wants to destroy everything good in life with their stupid emission's laws and ridiculous taxes for everything.

 

[Terry Lindsey]

The EGR valve should be close at idle. Open EGR at idle will cause the engine to run rough and stumble.

Actually the engine idles smooth with no hesitation or stumble and starts easily

 

[Pin_Head]

Hydrocarbon HC comes from misfiring or a leaky exhaust valve. Your measured level is way too high for the air injection system to deal with (even if you had a catalyst). Misfiring at idle is often due to lack of idle fuel or a manifold vacuum leak. 853 RPM is not idling and it should not have been tested at that high. The tech can adjust the idle speed. Maybe it won't run at 650 RPM, in which case start looking for vacuum leaks and plugged idle circuit.

 

[Terry Lindsey]

Hydrocarbon HC comes from misfiring or a leaky exhaust valve. Your measured level is way too high for the air injection system to deal with (even if you had a catalyst). Misfiring at idle is often due to lack of idle fuel or a manifold vacuum leak. 853 RPM is not idling and it should not have been tested at that high. The tech can adjust the idle speed. Maybe it won't run at 650 RPM, in which case start looking for vacuum leaks and plugged idle circuit.

 

[Terry Lindsey]

Thanks I’ll look into that. If a valve(s) is either too tight or too loose, would proper adjustment have any impact on HC and/or compression?

 

[Terry Lindsey]

Latest update... did a vacuum test with steady reading of 12 ( I’m at 3000’). Checked for vacuum leaks...all good. Checked my most recent valve adjustment... no bueno... too tight. Did a readjustment using the proper measurement this time and.... holy molly, what a difference that makes. Also I advanced timing a few degrees. As a result, engine smoothed out, I was able to adjust idle to specs, and....can start the beast without using the choke. I have no idea if it solved my HC issue but I bought myself another year by keeping it registered in AZ

 

[Jpilot]

Another thing that I have found is using Marvel Mystery Oil for a few hundred miles will clean out the accumulated carbon around the intake and exhaust valves. This can have a significant effect on your engine and HC numbers.