Can you de smog a motor with a stock carb?

[chevyfs]

Would it be possible to remove all the unessecary vaccum line off the carb and cap the holes? If so whats the minimum vac lines id need to run? 4.3liter V6 ‘86

 

[fast 99]

Short answer is yes, any things possible but do you want to poke the bear? I am currently doing one very similar but leaving it mostly stock. If the charcoal cannister is removed that will affect the tank venting. The EGR system can be removed at the risk of detonation. Air pump can go and won't affect drivability, only emissions. It's not just the carb, distributor curve, compression, cam, and every emission system are designed to work in concert. If it runs ok, what are you trying to accomplish?

 

[chevyfs]

Short answer is yes, any things possible but do you want to poke the bear? I am currently doing one very similar but leaving it mostly stock. If the charcoal cannister is removed that will affect the tank venting. The EGR system can be removed at the risk of detonation. Air pump can go and won't affect drivability, only emissions. It's not just the carb, distributor curve, compression, cam, and every emission system are designed to work in concert. If it runs ok, what are you trying to accomplish?

It kind of runs like ****, when i first start it in the morning it idles fine no problem just a little shaky in drive. But after its warmed up a bit i rev the engine then it drops down to a very low almost stalling idle, it also ticks at idle and under load but doesnt tick when gassed in park, the person who owned it before me has just took the smog pump belt off and all but the gas tank line have been removed from the canister, pcv also just runs straight to intake. Like you said the emissision system is designed to work together but would some of it being disconnected like thet cause problems?

 

[fast 99]

Check the choke pull-off for the cold condition. Can the idle speed be adjusted along with the idle mix? Air pump belt shouldn't affect operation. Ticking could be an exhaust leak, fan hitting the shroud, valve train issue, can you narrow it down? On the cannister thing, surprised there isn't a raw fuel smell.

 

[Bextreme04]

It kind of runs like ****, when i first start it in the morning it idles fine no problem just a little shaky in drive. But after its warmed up a bit i rev the engine then it drops down to a very low almost stalling idle, it also ticks at idle and under load but doesnt tick when gassed in park, the person who owned it before me has just took the smog pump belt off and all but the gas tank line have been removed from the canister, pcv also just runs straight to intake. Like you said the emissision system is designed to work together but would some of it being disconnected like thet cause problems?

Sounds like you have a vacuum leak that happens when one of the TVS's open up after the truck gets warm. The TVS's are thermally controlled vacuum valves that are screwed into the intake manifold. Post some pics of your engine bay and the current vacuum line routing

 

[Bextreme04]

And for the record, you don't need any smog anything... but you will need to make some definite changes if you don't have anything. I would suggest properly routing at least the charcoal canister to help with fuel vapor and fumes. The EGR is also beneficial if its working right. What normally happens is that a component fails, which makes the truck run terrible. Then the owner has no idea how to troubleshoot the problem and the smog parts are expensive, so they just remove or bypass the system.

 

[chevyfs]

Sounds like you have a vacuum leak that happens when one of the TVS's open up after the truck gets warm. The TVS's are thermally controlled vacuum valves that are screwed into the intake manifold. Post some pics of your engine bay and the current vacuum line routing

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heres a video of my engine bay. Dont mind the oily mess everywhere i think its a bad pcv valve

 

[fast 99]

Make sure the PCV system is working, both the vacuum and breather side. All that oil spray makes me question the condition of the engine. A compression test and leak down are something to consider.

 

[80BrownK10]

Make sure the PCV system is working, both the vacuum and breather side. All that oil spray makes me question the condition of the engine. A compression test and leak down are something to consider.

Look at his other thread on knock under load. There is something seriously wrong with that engine!

As to answer. You can cap off all that stuff and run a factory carb. As for the low idle that is probably just a carb adjustment and or vacuum leak type situation.

But the smog stuff, deleting it or making what you have run right should take a back seat to figuring out that noise that I don't believe is good.

 

[fast 99]

Look at his other thread on knock under load. There is something seriously wrong with that engine!

As to answer. You can cap off all that stuff and run a factory carb. As for the low idle that is probably just a carb adjustment and or vacuum leak type situation.

But the smog stuff, deleting it or making what you have run right should take a back seat to figuring out that noise that I don't believe is good.

Yeah, read that. Your right. From the pictures don't think the motor has much life remaining anyway. The blow by appears to be exceeding the PCV system capacity. Trying not to automatically condemn it. Poor compression would. The least of the problems are drivability.

 

[Bextreme04]

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heres a video of my engine bay. Dont mind the oily mess everywhere i think its a bad pcv valve

wow... that's a mess. I would start by making sure the motor is mechanically healthy. That amount of oil and other fluids is not usually due to a bad PCV. I'd run a compression test and depending on the numbers I got from that, potentially a leak down test. Once you know the health of the motor you can decide if you need to do anything else. Its pointless to try and fix anything on the motor if you have one or more dead cylinders. If the compression test shows good, then I'd degrease the hell out of that motor... clean everything you can and then replace any bad gaskets and seals. Then once that is done, start tracing all of those vacuum lines and check for damaged or dry rotted hoses. The good news is that you have the vacuum diagram right there on the air cleaner. Just trace the hoses and make sure they are all connected where they need to go.

 

[AuroraGirl]

wow... that's a mess. I would start by making sure the motor is mechanically healthy. That amount of oil and other fluids is not usually due to a bad PCV. I'd run a compression test and depending on the numbers I got from that, potentially a leak down test. Once you know the health of the motor you can decide if you need to do anything else. Its pointless to try and fix anything on the motor if you have one or more dead cylinders. If the compression test shows good, then I'd degrease the hell out of that motor... clean everything you can and then replace any bad gaskets and seals. Then once that is done, start tracing all of those vacuum lines and check for damaged or dry rotted hoses. The good news is that you have the vacuum diagram right there on the air cleaner. Just trace the hoses and make sure they are all connected where they need to go.

In addition, his carb was wet. And area around it. Was that gas? Water? If it was gas Id be worried about a fire too.

And on the vacuum thing, is this thing a california emissions? The label will say it meets 1986 Federal or (maybe and?) California emissions on the label that he mentioned the diagram is on. The large amount of the ones coming off the one side of the engine makes me wonder that.

I just did a quick google and found that the Deceleration Valve on the diagram he posted, is a real thing, it was common on the v6s in like F bodies apparently too, and its tied in with PCV and AIR systems, on yours apparently Evap too. But if there was a check valve or bad hoses there, you could have pcv then spraying all over possibly or maybe not venting normally. i would If I were him, when he gets to the cleaning stage, to bypass the componennts T'ed into the PCV part and go straight to the PCV, and then making sure the EGR and --.. no, I just looked again. Too many things are tied into eachother to just try and bypass that one component, for simplicity. Hes got a vacuum switch, a solenoid for idle, other check valves that will be disturbed if they arent happy. Maybe he should do a minimal hookup approach.

I would say, is there any concerns leaving the spark retard valve and other things touched. if He has a vacuum spark retarding valve, is his ignition timing off a normal setting that he would then have improper timing?

 

[chevyfs]

In addition, his carb was wet. And area around it. Was that gas? Water? If it was gas Id be worried about a fire too.

And on the vacuum thing, is this thing a california emissions? The label will say it meets 1986 Federal or (maybe and?) California emissions on the label that he mentioned the diagram is on. The large amount of the ones coming off the one side of the engine makes me wonder that.

I just did a quick google and found that the Deceleration Valve on the diagram he posted, is a real thing, it was common on the v6s in like F bodies apparently too, and its tied in with PCV and AIR systems, on yours apparently Evap too. But if there was a check valve or bad hoses there, you could have pcv then spraying all over possibly or maybe not venting normally. i would If I were him, when he gets to the cleaning stage, to bypass the componennts T'ed into the PCV part and go straight to the PCV, and then making sure the EGR and --.. no, I just looked again. Too many things are tied into eachother to just try and bypass that one component, for simplicity. Hes got a vacuum switch, a solenoid for idle, other check valves that will be disturbed if they arent happy. Maybe he should do a minimal hookup approach.

I would say, is there any concerns leaving the spark retard valve and other things touched. if He has a vacuum spark retarding valve, is his ignition timing off a normal setting that he would then have improper timing?

Whoever owned it before me already bypassed all the pcv crap cause the pcv hook straight up to the manifold(i 100% need a new pcv) all the other stuff a redneck got his hands on so theres already bolts in vacuum lines and what not. The vacuum advance isnt even hooked up. In genral everything already been unhooked and messed up for the most part

 

[AuroraGirl]

Whoever owned it before me already bypassed all the pcv crap cause the pcv hook straight up to the manifold(i 100% need a new pcv) all the other stuff a redneck got his hands on so theres already bolts in vacuum lines and what not. The vacuum advance isnt even hooked up. In genral everything already been unhooked and messed up for the most part

MANIFOLD?

 

[chevyfs]

MANIFOLD?

Intake manifold