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305 SBC
Jun 13, 2005 10:30:22 GMT -5
Post by kringold on Jun 13, 2005 10:30:22 GMT -5
Once the weather improves and finances allow I want to get this thing done. I'll be working on the vacuum lines next. Now here is what I have been pondering, the definition of a TVS is as follows; thermal vacuum switch: (TVS) [1] measures either air/fuel temperature, underhood temperature, or coolant temperature, or a combination of any two to regulate the EGR valve accordingly. [2] A temperature sensitive switch that shifts the source of the advance from ported to manifold vacuum when coolant temperature reaches approx 225 deg F or thermal vacuum valve: (TVV) A valve with the same function as a thermal vacuum switch. TVS units, which serve to interrupt exhaust gas recirculation when the temperature is too low, are located in the vacuum line between the ECR valve and inlet manifold or carburetor Seen as how I am leaving off the EGR, do I even need a TVS? So I was thinking that I might/could be able to go without a TVS, and in it's place, have a fitting with a single vacuum line to the the canister purge valve for control vacuum. Or, perhaps get that control vacuum from another source, ie. off the PCV, and just plug the hole in the intake manifold. What are your thoughts? This topic is being discussed in the follwing thread also. hotrodders.com/showpost.php?p=465603&postcount=11
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305 SBC
Jun 13, 2005 12:20:04 GMT -5
Post by Venturi on Jun 13, 2005 12:20:04 GMT -5
Hey kringold,
I know I’m coming in a little late on your project and this has probably been asked before but are you completely doing away with the computer control system and replacing the carb and dist or are you planning on using the computer controls? This makes a big difference when it comes to deciding what options you have when eliminating certain components.
On the TVS thing, the majority of the EGR valves were not controlled by a TVS in ‘84, the vacuum supply to the valve was regulated by the vacuum control solenoid operated by the computer. You should’ve originally had 2 TVS switches; one controlled the canister purge via the canister control valve and the other controlled vacuum to the EFE damper in the exhaust manifold. If you plan on using the carbon canister purge system it would be best to use the TVS rather than by-passing it with direct vacuum. If you by-pass the TVS, canister purging will not be temperature controlled and it may cause cold drivability problems. The same is true for the EFE, if you are using the stock exhaust manifolds the vacuum to the EFE damper must be regulated by a TVS. If vacuum is directly routed to the EFE it will remain closed at all times causing a restriction to exhaust flow. Of course you can always leave the EFE vacuum disconnected but this may cause slower warm ups and cold drivability problems in very cold temperatures.
Did this answer your question?
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305 SBC
Jun 13, 2005 20:17:51 GMT -5
Post by kringold on Jun 13, 2005 20:17:51 GMT -5
Hey kringold, I know I’m coming in a little late on your project Yeah I missed ya. I PM'd you a while back on Kurt's forum looking for your help. I wondered where you went! are you completely doing away with the computer control system and replacing the carb and dist or are you planning on using the computer controls? I'm keeping computer, carb. and distributor, and plan on using the computer, cuz the carb will need it. On the TVS thing, the majority of the EGR valves were not controlled by a TVS in ‘84, the vacuum supply to the valve was regulated by the vacuum control solenoid operated by the computer. You should’ve originally had 2 TVS switches; one controlled the canister purge via the canister control valve and the other controlled vacuum to the EFE damper in the exhaust manifold. If you plan on using the carbon canister purge system it would be best to use the TVS rather than by-passing it with direct vacuum. If you by-pass the TVS, canister purging will not be temperature controlled and it may cause cold drivability problems. This I think answered my question. The same is true for the EFE, if you are using the stock exhaust manifolds the vacuum to the EFE damper must be regulated by a TVS. If vacuum is directly routed to the EFE it will remain closed at all times causing a restriction to exhaust flow. Of course you can always leave the EFE vacuum disconnected but this may cause slower warm ups and cold drivability problems in very cold temperatures. Okay now you are talking Greek to me. EFE? Is that the system with the flex-pipe running from the exhaust manifold to the air cleaner? If so then that was gone ages ago. The flexpipe was just laying in the engine compartment when we got the car, and I have since swapped out air cleaners. early fuel evaporation system: (EFE) A system that heats the inlet manifold to provide a warm air/fuel mixture, reducing condensation and improving fuel evaporation, thus improving cold engine operation and reducing exhaust emissions. An EFE system operated by engine exhaust gas responds quicker to engine heat-up than systems heated by engine coolant; some EFE systems use an electric heater in the intake duct
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305 SBC
Jun 13, 2005 22:32:34 GMT -5
Post by Venturi on Jun 13, 2005 22:32:34 GMT -5
Yeah I missed ya. I PM'd you a while back on Kurt's forum looking for your help. I wondered where you went! I had a little mishap with a 1.5 ton Cadillac that decided to T-bone my car back in January. I was out of commission until the later part of April. I just recently got the internet back at home…….had to go to a friend’s house to get online for a while. Sorry for the confusion, the EFE I’m referring to is the damper valve in the exhaust manifold, I think it’s on the passenger side manifold. It should have had a metal tube going to it from one of the TVS switches. It redirects a certain amount of exhaust through a passage in the intake to the other head to help warm and atomize the fuel/air mixture when the engine is cold. Are you using the stock intake and exhaust manifolds?
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305 SBC
Jun 14, 2005 1:04:05 GMT -5
Post by kringold on Jun 14, 2005 1:04:05 GMT -5
Yes I'm using the stock exhaust manifolds. I just plugged the holes for the A.I.R. system that where in them. I don't remember any tube running from them to the intake manifold tho and there is no open holes in them for one. I'll double check, but I don't think so. I am using a new intake manifold. An Edelbrock Performer #2101. www.edelbrock.com/automotive_new/mc/manifolds/chevy_sb_perf.shtml
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305 SBC
Jun 14, 2005 11:33:58 GMT -5
Post by Venturi on Jun 14, 2005 11:33:58 GMT -5
kringold, I think you’re going to be very disappointed with the performance of this engine. When you start eliminating components like the EGR valve and the Air Management system the computer is going to think these systems are malfunctioning and will set the fuel mixture and ignition timing advance at preset values and leave them there. This is what is called Limp-in mode, it’s enough to keep the car running but it will be a major dog.
If you plan on using the computer system ALL of the original components must be in place. Otherwise the computer will default to Limp-in mode and you might as well take the ECM out and toss it in the garbage can.
I think you need to decide whether you’re going to use the computer system in its entirety or do a way with it and go to a non feed back system, if that’s even an option in your state. If your state has emissions testing it may greatly limit what you can and can not do depending on how strict the standards are.
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305 SBC
Jun 15, 2005 15:30:50 GMT -5
Post by kringold on Jun 15, 2005 15:30:50 GMT -5
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305 SBC
Jun 17, 2005 7:47:45 GMT -5
Post by kringold on Jun 17, 2005 7:47:45 GMT -5
So I guess where we are at is I need to buy the TVS and then plug the open port(s)? The intake manifold that I'm using is a non-EGR one so there wouldn't be the passage for the EFE to work even if it was there, am I right? Another question too is should I use manifold vacuum or ported vacuum for the distributor?
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305 SBC
Jun 17, 2005 8:57:35 GMT -5
Post by Venturi on Jun 17, 2005 8:57:35 GMT -5
So I guess where we are at is I need to buy the TVS and then plug the open port(s)? A TVS for what, the canister? The intake manifold that I'm using is a non-EGR one so there wouldn't be the passage for the EFE to work even if it was there, am I right? That depends on the intake, some have crossover ports and some don't. I wouldn't worry about the EFE, even if it was there originally you can live without it. It's not controlled or monitored by the computer. Another question too is should I use manifold vacuum or ported vacuum for the distributor? OK, now I'm confused, or you using the computer controlled dist or are you using a non controlled dist?
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305 SBC
Jun 17, 2005 9:23:00 GMT -5
Post by kringold on Jun 17, 2005 9:23:00 GMT -5
There is no place to plug in the EST connection so I believe a non computer controlled. A little history here. When I was running the oil pump primer that I got from AutoZone it didn't fit the shaft for the oil pump right and the primer tool was just spinning on top of the oil pump driveshaft. I had a box that I was storing two distributors in. One for this vehicle and another that I had pulled off a dead Chevy van (engine siezed cuz, the owner didn't put any oil in it until it was too late). I pulled one out and modified it so I could use it to prime the engine with. I thought both were the same but evidently not. So I think I have the one off the van installed.
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305 SBC
Jun 17, 2005 15:28:28 GMT -5
Post by Venturi on Jun 17, 2005 15:28:28 GMT -5
Well if you have the wrong dist in the car the computer will definitely go into Limp-in mode because it will have no RPM reference. You might as well just pull the computer out if that's the case, everything will default to presets and the carb will run full rich.
Chevy usually runs full-time manifold vacuum to the vacuum advance on the dist but that's not set in stone, you can try it both ways to see which performs better.
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305 SBC
Jun 17, 2005 20:22:35 GMT -5
Post by kringold on Jun 17, 2005 20:22:35 GMT -5
"You might as well just pull the computer out if that's the case, everything will default to presets and the carb will run full rich."
If the carb is goig to run full rich, would I be able to lean it out?
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305 SBC
Jun 17, 2005 23:09:45 GMT -5
Post by Venturi on Jun 17, 2005 23:09:45 GMT -5
No, there's is really nothing that you can adjust on the Quadrajet E4ME that will lean it out besides the base idle mixture screws. And I doubt that would have the desired effect because the idle air/fuel mixture is mainly controlled by the M/C solenoid in conjunction with the idle air bleed. This carburetor is not intended to work in the way you are trying to use it, there are no "work-arounds" or tweaks you can use to make it do what is was not designed to do. When the computer goes in to Limp mode the M/C solenoid stops cycling and the air/fuel mixture goes to max rich.. It doesn't matter what you tweak, twist, pull or bang on, that's just the way it is.
I'm not saying that it won't run because by all rights it should but the performance and fuel mileage will definitely suck.
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305 SBC
Jun 18, 2005 5:11:25 GMT -5
Post by kringold on Jun 18, 2005 5:11:25 GMT -5
I guess I'm back to this question then.
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305 SBC
Jun 24, 2005 15:59:29 GMT -5
Post by kringold on Jun 24, 2005 15:59:29 GMT -5
Well Saturday the 25th is my birthday, and I think it would be kinda nice if I could fire this bad boy up then. I'm going with this carb. only till I can get a new one. This car won't be driven 'til then. So, what vacuum hoses do I need hooked up and to where, to just run it to break in the engine for about 30 minutes?
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