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| Re: [GMCnet] Smog Coming in High [message #257923 is a reply to message #257913] |
Tue, 05 August 2014 21:40   |
lotsofspareparts
Messages: 726
Registered: May 2014
Location: Arlington, WA
Karma: -9
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Well after 33 postings in the last year I would say get a can of the stuff that guarantees you will pass emissions.
I imagine if you posted more you may have gotten a better response.
I have used it with older cars I have owned, and it did work.
Jared & Tina Lazaron + 14yr old Daughter.....
77 Eleganza II "Recherché".....
73 Canyon Lands 230 "Elephant"
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| Re: [GMCnet] Smog Coming in High [message #257927 is a reply to message #257913] |
Tue, 05 August 2014 22:27 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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AlexPosner wrote on Tue, 05 August 2014 19:24Hey Guys,
We are trying to smog the '76 Eleganza II and having trouble. We are looking at the carb, replacing the float needle... Anything else we should be looking at? Any suggestions? It's coming in really high.
Thanks,
Alex
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Set the idle screws as lean as you can and still have it idle. Then retard the timing. If necessary run a bit of E85.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: [GMCnet] Smog Coming in High [message #257929 is a reply to message #257927] |
Tue, 05 August 2014 22:44 |
Carl S.
Messages: 4186
Registered: January 2009
Location: Tucson, AZ.
Karma: 13
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Usually high HC is due to ignition problems (a miss). Carburetor idle air mixture settings can cause either one, if too lean, it will cause a miss, resulting in high HC readings, too rich can cause a high Co reading. Like Bob suggested, retard the timing and adjust the idle air mixture screws in until it starts to run rough, then back off about 1/2 turn. That should get you close if the rest of your ignition system (especially spark plugs and wires) is in good condition.
Carl Stouffer
'75 ex Palm Beach
Tucson, AZ.
Chuck Aulgur Reaction Arm Disc Brakes, Quadrabags, 3.70 LSD final drive, Lenzi knuckles/hubs, Dodge Truck 16" X 8" front wheels, Rear American Eagles, Solar battery charging. GMCSJ and GMCMI member
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| Re: [GMCnet] Smog Coming in High [message #257933 is a reply to message #257913] |
Tue, 05 August 2014 23:13 |
mrgmc3
Messages: 210
Registered: September 2013
Location: W Washington
Karma: 2
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You said the results were "high" but gave no breakdown. If you can report your idle HC, CO and NOx as well as your 2500 rpm HC, CO and NOx it would be very helpful to provide further guidance. (I can't remember for sure if they report NOx or just HC and CO...my smog test printout is 1500 miles away at present)
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 54k mi
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| Re: [GMCnet] Smog Coming in High [message #257935 is a reply to message #257933] |
Tue, 05 August 2014 23:37 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Send me your print out and I should be able to advise you..
Smog is not a bad hing , as it can tell you if you have a weak engine.
Customers that have been having problems passing will drop their coach off
and we determine what is causing it from performing properly.
I have seen lot of coaches come in with unhooked emission thinking it will
help, instead it hurts the performance and mileage.
On Tue, Aug 5, 2014 at 9:13 PM, Chris Geils
wrote:
> You said the results were "high" but gave no breakdown. If you can report
> your idle HC, CO and NOx as well as your 2500 rpm HC, CO and NOx it would
> be very helpful to provide further guidance. (I can't remember for sure
> if they report NOx or just HC and CO...my smog test printout is 1500 miles
> away at present)
> --
> Chris Geils - Twin Cities
> 1978 26' Kingsley w/ very few mods; Headers, Progressive Dynamics 9040
> battery charger, aux trans cooler, one repaint in stock colors, R134a, 44k
> mi
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
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>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] Smog Coming in High [message #258148 is a reply to message #258123] |
Fri, 08 August 2014 00:59 |
mrgmc3
Messages: 210
Registered: September 2013
Location: W Washington
Karma: 2
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ryanposner wrote on Thu, 07 August 2014 19:32 (bottom is the more recent of the two - before and after above technique)
Please let me know if you have any thoughts! Thanks very much.
Yes, you have managed to lean out the mixture as evidenced by the large drop in CO. HC has tripled and is a flunk now. You are probably inducing lean misfire at idle. This will result in unburned fuel (or HC). I assume this set of data is the idle test.
You can tweak and retest, but it can take several tries. I would recommend a carb rebuild kit and a new float. Set the float level at the prescribed point or maybe 1/16" lower. Set the idle mixture as prescribed in the earlier post. This should get you close if you don't have vacuum leaks due to old / misrouted lines, or worn throttle shafts. Also check for intake gasket air leaks.
The idle mixture screws will have a large affect on the idle values, the float level and jetting (I assume it is stock) will have more impact on the 2500 rpm point.
If you know anyone with a linear lambda meter borrow it. Set your A/F to 14-14.5 at idle. Set the neutral rev 2500 point to 15:1. Don't worry about ignition timing as long as you are close, it has little affect on HC or CO (a lot on NOx).
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 54k mi
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