Home » Public Forums » GMCnet » Passing Smog
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 Re: Passing Smog [message #271133 is a reply to message #271125] |
Tue, 03 February 2015 19:24   |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
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Senior Member |
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Jarrar wrote on Tue, 03 February 2015 17:27How are you?
I have a 1977 GMC 23ft transmode.
Went to smog it yesterday/Monday and it did not pass.
I drove it about 30 miles on Sunday and about 6 miles on the freeway on Monday before I went for the smog check. I also left it running till the mechanic got to it. I had put $50 of fresh gas in the tanks on Sunday.
The part that it failed is the Idle test which according to the paper was at 928 RPM. I looked at the RPM gauge in the RV and the idle is at 750 in Park and around 600 in N.
So why is this idle at 928 RPM?
It failed the CO measuring at 5.11 and the maximum is 3.00
Any advice on what I can do please to make it pass ?
Thank you,
AJ
It sounds like your tach is off. Also, I don't understand why the RPM would be different in park vs neutral--did you mean drive? A lower rpm will help and I would lean out the idle mixture screws into the zone where the idle rpm is going down as you scrw them down. You can always bsck them out later.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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| Re: Passing Smog [message #271293 is a reply to message #271125] |
Fri, 06 February 2015 10:07 |
mikeceli
Messages: 20
Registered: January 2015
Location: N. Ca.
Karma: 1
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Junior Member |
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http://www.carsdirect.com/car-maintenance/7-common-reasons-for-failing-an-emissions-test
Cali wants the OP's GMC and all older vehicle, CRUSHED.
I recommend you NOT deviate from OE tuning specs(plug gap) , except perhaps retard the ignition timing 2-3 degrees. (cali allows only so much timing retard/advance or it's an automatic failure. I'm not sure how much, 2-4 degrees or so)
This sounds like a job for someone like Applied GMC, in Newark, Ca. The ignition system, carb, catalytic converter should be tested and repaired as indicated.
If you feel you can.........spray a can of carb cleaner, in the carburetor, slowly while keeping the engine running. CAUTION MUST BE DONE PROPERLY TO NOT CATCH FIRE After cool down, Id pull the plugs again, put 3 OZ. of Seafoam (avail at NAPA, O'Reilly's, Walmart) in each cylinder. Let it sit, overnight, then before installing the plugs, crank the engine to expel the Seafoam. Install new or KNOW GOOD set of OE spec spark plugs.
(NOT Bosch Platinums)!
These procedures will make smoke like HecK! Possibly not doable in SC, CA. Your gonna want to change the oil and filter, after the above treatments.
The ignition wires, cap, rotor, coil will need testing, professionally if you don't have the tools and knowledge.
You might end up needing a new CAT (if originally equipped). Cats are tested by measuring the input and output temps, with the engine running. Also, strike w/ rubber mallet, to hear loose, cracked substrate. If you have the OE "Pellet" CAT, it's likely failed. That is another "cali NIGHTMARE! Cats must be CA. Certified which raised the prices from approx. $80.00 to $400.00.
THEN, the idle will need to be set to OE range.
GOOD LUCK!
[Updated on: Fri, 06 February 2015 10:09] Report message to a moderator |
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| Re: [GMCnet] Passing Smog [message #271294 is a reply to message #271293] |
Fri, 06 February 2015 10:36 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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Senior Member |
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What CATALYTIC CONVERTER are you talking about?
Are you really not aware that the GMC motorhome was never equipped with a catalytic converter?
Emery Stora
> On Feb 6, 2015, at 9:07 AM, Mike Celi wrote:
>
> http://www.carsdirect.com/car-maintenance/7-common-reasons-for-failing-an-emissions-test
>
> Cali wants the OP's GMC and all older vehicle, CRUSHED.
>
> I recommend you NOT deviate from OE tuning specs(plug gap) , except perhaps retard the ignition timing 2-3 degrees. (cali allows only so much timing
> retard/advance or it's an automatic failure. I'm not sure how much, 2-4 degrees or so)
>
> This sounds like a job for someone like Applied GMC, in Newark, Ca. The ignition system, carb, catalytic converter should be tested and repaired as
> indicated.
>
>
> If you feel you can.........spray a can of carb cleaner, in the carburetor, slowly while keeping the engine running. After cool down, Id pull the
> plugs again, put 3 OZ. of Seafoam (avail at NAPA, O'Reilly's, Walmart) in each cylinder. Let it sit, overnight, then before installing the plugs,
> crank the engine to expel the Seafoam. Install new or KNOW GOOD set of OE spec spark plugs.
> (NOT Bosch Platinums)!
>
> These procedures will make smoke like HecK! Possibly not doable in SC, CA. Your gonna want to change the oil and filter, after the above treatments.
>
>
> The ignition wires, cap, rotor, coil will need testing, professionally if you don't have the tools and knowledge.
>
> You might end up needing a new CAT (if originally equipped). Cats are tested by measuring the input and output temps, with the engine running.
> Also, strike w/ rubber mallet, to hear loose, cracked substrate. If you have the OE "Pellet" CAT, it's likely failed. That is another "cali
> NIGHTMARE! Cats must be CA. Certified which raised the prices from approx. $80.00 to $400.00.
>
> THEN, the idle will need to be set to OE range.
>
> GOOD LUCK!
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
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| Re: [GMCnet] Passing Smog [message #271336 is a reply to message #271318] |
Sat, 07 February 2015 02:07 |
Olly Schmidt
Messages: 1265
Registered: February 2014
Location: Germany and Scottsville, ...
Karma: 8
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Senior Member |
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Hello Mike,
> [..]
>
> Did you not read my post?
That was uncalled for. Comes over very nasty from my point of view, even
if you probably didn't intend any nastiness. This is the GMC Motorhome
place. If you copy/paste stuff from another source, it might make sense
to verify that the statements in there are applicable.
> [..]I am considering purchasing one, not an owner. Twenty years automotive experience, almost no Motorhome experience.
It is great to have someone with long experience around. Welcome.
And when you do have a GMC Motorhome, go and enjoy it.
--
Best regards
Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA
'76a Eleganza II, VA
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Best regards
Olly Schmidt
PGP Key ID: 0x18a9 3a1f 4196 bf22
'76a Eleganza II, VA
'73 Sequoia, SH, Germany
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