Emmisions

Emmisions UPDATE!!!!!!!

I took my 71 V6 for its test on Friday after tuning it up and the readings were super low and passed with flying colors but it failed because of visual smoke which only happens after it idles for a while and then smokes when you crack the throttle. I really don't think its oil but rather the carb loading up(really black). I have a free test if I take it back within 10 days. Does anyone have any ideas. Update! 5-16-06 Well I rebuilt the carb and went with smaller jets and installed valve stem seals and the black smoke was still there. I dug into the issue and I new it was simple because it didn't appear to smoke before! So I started the process of elimination and I tested the new distributor I had put in and sucked on the vacume advance hose and it had a serious leak in the vacume advance. Replaced and problem solved!

 

If it's carbon, a little Marvel Mystery Oil in the gas is supposed to help clean it out.

Jim

 

I would think it is running a little rich. adjust your idle mixture screws to lean it out some and see if that helps.

 

Ditto!!
Unless they're giving you lots of room for error theres no way that vehicle actually passes the test.

 

I have them turned in as much as possible(about 3/4 turn out). What do you think about jetting it down some? My HC PPM readings were 128 at 2500rpm and 154 at idle (limits are 1000) CO% was
.62 at 2500 and .16 at idle (limits were 4.50)

 

what were your NOx reading?

 

No NOx readings were on the sheet.

 

jet down some, limp over to the test site and run it..then when clear, jet back to what's right.
just a thought.

 

I think some carb work is in order
two different circuits of the carb giving high readings
idle circuit is different than the main metering circuit
changing the jets won't change a thing at idle, only at cruise, 2500 RPM
sounds more like loose screws/bad gaskets to me

 

Update on first post!