'83 Chevy Motorhome - Passing CA Smog Check
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'83 Chevy Motorhome - Passing CA Smog Check

  1. #1
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    Default '83 Chevy Motorhome - Passing CA Smog Check

    I'd like to register my Dad's 23' RV that I brought to CA from AZ recently. It has a 454 BBC (65k miles) that I tried to smog last week....and it failed. The smog tech said not to touch the carb as it was dialed in, but that it has a miss that's the likely culprit of why it failed. Looking at the smog report, the motor did excellent at the 2500 rpm test, but registered as a gross polluter spewing twice the legal limit if hydrocarbons during the idle test.

    So I'm thinking of doing a basic tune up and testing it again, but want to get some feedback about whether it's worth putting any more $ into this beast. All in all this RV is in decent shape, it handles well, and it towes the toys well. So I'd like to keep it.

    Besides changing plugs, wires, cap, rotor, points and setting the timing....do you have any other suggestions? Also, what should I set the timing to here in San Diego?

    Thx
    Last edited by piezzi; 02-20-2009 at 09:09 PM.

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    New here Beer:30's Avatar
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    Depending on the year, it may have an HEI distributor. Being '83, it SHOULD be. If not, I would stick one in. As long as it is a stock, direct replacement piece, it would still pass the visual inspection. If you end up replacing a points dist with HEI, that will take care of most of your tune up. You would need new wires anyway (for the HEI) and plugs are really the only thing left.

    If it DOES have points, you can go another route and put in a Pertronix module kit. It would be even safer, as the distributor would appear stock, but be similar to HEI inside.

    Either way, it would probably be the last time you would ever have to tune it.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

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    Senior Member BrianB's Avatar
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    I've been down this road, it can be frustrating.

    Don't forget the thermostat along with a fresh oil change and some decent midgrade gas.
    If you get her all tuned up and running well the engine temp should be around 195 for smog.

    Good Luck

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    Senior Member GT Jets's Avatar
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    Motorhomes are notorious for vacuum leaks, make sure to try and find all of them, typically when they fail the idle test its do to high hydrocarbons (unburned fuel), if you have the data sheet, it should say what it failed on..

    You can use an ultrasonic leak detector to find the leak (sometimes called a vacuum sniffer), also if you can find a place in your area that sells methanol, try mixing about 25% methanol in the fuel and make sure she's hot as hell when you do the test, 454's intakes tend to get intake leaks fairly easy, especially if they have an alumunim intake, does this one have an EGR?, might check that out too.

    I have a 1984 454 motorhome with an Air Sensors Inc. Fuel injection system on it and it passes with flying colors, has EGR, Evap, Air injection, everything but a damn CAT. Vacuum leaks are its only downfall.

    Do you guys have the option of a pre test, we can do that here for about $30? Basically it makes sure it will pass before putting into the system.

    Good luck!

    edit; I want to say the initial ignition timing is like 4* BTDC but not sure.

    GT
    Last edited by GT Jets; 02-21-2009 at 11:27 AM.
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    I've never heard about the pre-test here in CA.

    Not sure if it has an EGR, but it appears to have the HEI distrib (see pic). So should I still get a new cap and rotor? What about the coil....should I also replace this?

    I've noticed a bit of a stumble upon initial acceleration lately, so a vaccum leak could very well be part of the problem.

    The air cleaner displays the timing specs and GT's right, its 4*. Also, this RV has an MSD manual timing adjustment controller (see pic).

    When I had the smog test, it only failed the HC idle test. It registered a 449, and 400 = GP. Max allowable is 250.
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    Senior Member GT Jets's Avatar
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    You should be able to to a pre test (you need to ask them) smog only technically can't, but might if you ask them.

    HC or hydrocarbons is a dead miss, causes are many, low compression, vacuum leak, bad plug or wire (a scope would find this in a heartbeat), a wet or bad cap/rotor, wrong idle adjustment on the mix screws etc....

    As far as the hesitation it almost sounds like a stuck open EGR, but I can't see one in you're pics, this would also cause the high HC, the EGR should be totally closed at idle.

    I would get it cleaned up (steam clean in your area?) and spray some WD40 or carb cleaner around the carb base and the intake manifold to see if the idle changes...If the canister purge valve is jacked that will cause high HC also, it's just unburned fuel, I'm betting a carb problem...

    I would throw some basic tune up parts at it and see what sticks, you can always keep the good used stuff for spares.


    GT
    Last edited by GT Jets; 02-21-2009 at 06:29 PM.
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    New here Beer:30's Avatar
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    I would bet just an HEI tune-up kit; cap, rotor, module, coil, wires and plugs would make a tremendous improvement. Especially since the engine looks like it hasn't been touched since 83. Probably easiest just to get a rebuilt distributor, since it would also include the vacuum advance which could also be rotten.
    Last edited by Beer:30; 02-21-2009 at 06:37 PM.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

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    Senior Member GT Jets's Avatar
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    I don't like the routing of plug wire three, there is a good chance for cross firing, just another opinion...

    GT
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  11. #9
    Senior Member GT Jets's Avatar
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    What it's supossed to look like

    GT

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    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

  12. #10
    New here Beer:30's Avatar
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    Wow. AirSensors! That brings back memories. I used to work for a company that was in the back of an RV service center. They installed these things all the time. Worked really well, given the technology of the time.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

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    Senior Member GT Jets's Avatar
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    Quote Originally Posted by Beer:30 View Post
    Wow. AirSensors! That brings back memories. I used to work for a company that was in the back of an RV service center. They installed these things all the time. Worked really well, given the technology of the time.

    Yeah she runs good, just wish it was a closed loop system, can't figure out how to convert it...It has bigger injectors now, runs like it's scared and still gets 12+/- MPG if you drive it like an old man..

    GT
    GT


    Quote Originally Posted by Quickjet View Post
    Put a 300 on the back of it, Flywheel it and a nosecone. $15,000 later you'll have a 65 mph pile of shit......

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    New here Beer:30's Avatar
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    Quote Originally Posted by GT Jets View Post
    Yeah she runs good, just wish it was a closed loop system, can't figure out how to convert it...It has bigger injectors now, runs like it's scared and still gets 12+/- MPG if you drive it like an old man..

    GT
    Yeah, I don't know of any way to closed loop that. About the only thing you could do is run an a/f monitor and adjust accordingly. Sounds like it is pretty dialed in, though. I never knew them to get much better mileage than that on big blocks.
    Quote Originally Posted by gn7 View Post
    EFI is the wave of the future. There can be no denying it. Electronics have been on the leading edge of our entire lives. Not only os the magneto dead, but the standard issue CDI is wavering. Its all about total fuel, air AND spark control. Anybody that thinks its not has their head up their ass.


    2001 SleekCraft 30' Heritage SSB, open-bow mid-cuddy. 496HO / Bravo-I.

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    Thanks guys. I'll get her cleaned up, throw some tune up parts on, and test for vaccum leaks.

  16. #14
    ptz
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    check for vacuum leaks.

    is the co 2 high at idle ?

    get a book and check how many turns the fuel screws are out.

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