Carb causing Emmisions Problems
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Senior User
Joined: Oct 2002
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From: houston
Carb causing Emmisions Problems
Hi all,
I'm having trouble passing my emmisions test in Texas. I'm running about 1314 ppm hydrocarbons where the limit is 500 ppm. Same vehicle, same testing station did 86 ppm last year.
In the last year I've replaced my egr valve, plugs, cap and rotor. Smog pump is hooked up, tested it is pumping air and can pump into the heads ie nothing plugging it up.
I can't think of anything else to fix/replace to get it better.
Vehicle has no cats from the factory.
Carb is a factory autolite holly I'm pretty sure. This is on a motorhome and it does sit at times for 2-3 months without being run (not good I know).
What can a shop to to clean / tune-up my carb. I don't think I would want them to rebuild it for 100 or more as I could just get a new carb for under 300. I know nothing about carbs.
Thanks for your advice!
Dave
I'm having trouble passing my emmisions test in Texas. I'm running about 1314 ppm hydrocarbons where the limit is 500 ppm. Same vehicle, same testing station did 86 ppm last year.
In the last year I've replaced my egr valve, plugs, cap and rotor. Smog pump is hooked up, tested it is pumping air and can pump into the heads ie nothing plugging it up.
I can't think of anything else to fix/replace to get it better.
Vehicle has no cats from the factory.
Carb is a factory autolite holly I'm pretty sure. This is on a motorhome and it does sit at times for 2-3 months without being run (not good I know).
What can a shop to to clean / tune-up my carb. I don't think I would want them to rebuild it for 100 or more as I could just get a new carb for under 300. I know nothing about carbs.
Thanks for your advice!
Dave
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
Carb causing Emmisions Problems
Sounds like an air bleed is plugged, causing an overly rich mixture, or there is fuel leaking internally in the carb. You may also want to pull the air filter out and make sure nothing made a nest in there since the last drive. Having the carb rebuilt is a fairly cheap option, and depending on the engine and year of the vehicle, rebuilt factory carbs can be had for fairly cheap too.
Thread Starter
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Senior User
Joined: Oct 2002
Posts: 128
Likes: 0
From: houston
Carb causing Emmisions Problems
Ok,
I'm going to call the shop "gasp" and see what they can do for me. I'm just a total do it yourself type person but don't have the skills to tackle my carb.
Few other things to note.
1. Engine is difficult to start at times when cold, maybe my choke isn't working.
2. After enging is hot ie running an hour or so the idle is not so great, feels like a lumpy cam, but doen't have a lumpy cam.
3. Even after a new 4 row radiator, hd fan clutch, new 180 t stat, water pump, I'm still running about 205-210 on the highway. Granted I'm in a class c rv that weights probably 8-9k lbs. Could the carb have anything to do with the running hot issue? Ie if it was lean could it make it run hotter?
Maybe having some carb work done isn't a bad idea?
Thanks for the advice
Dave
I'm going to call the shop "gasp" and see what they can do for me. I'm just a total do it yourself type person but don't have the skills to tackle my carb.
Few other things to note.
1. Engine is difficult to start at times when cold, maybe my choke isn't working.
2. After enging is hot ie running an hour or so the idle is not so great, feels like a lumpy cam, but doen't have a lumpy cam.
3. Even after a new 4 row radiator, hd fan clutch, new 180 t stat, water pump, I'm still running about 205-210 on the highway. Granted I'm in a class c rv that weights probably 8-9k lbs. Could the carb have anything to do with the running hot issue? Ie if it was lean could it make it run hotter?
Maybe having some carb work done isn't a bad idea?
Thanks for the advice
Dave
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