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| Runs, but not after given gas https://slantsix.org/forum/viewtopic.php?t=23579 |
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| Author: | 73dartcustom [ Tue Jun 12, 2007 10:13 pm ] |
| Post subject: | Runs, but not after given gas |
I just got my 74 dart running but I am having a problem with the stock holley 1945. The problem is that after I give it gas for the first time after warming up it dies upon letting off the gas. Other than that it runs and idles fine while warming up and revs up just fine when given gas. I recently took apart the carb and basically cleaned it out real good and replaced a few of the parts provided by the $24 napa kit. The car has almost 30,000 original miles and the carb seemed to be in good shape. Any information would be greatly appreciated. |
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| Author: | SlantSixDan [ Tue Jun 12, 2007 10:21 pm ] |
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1974 was the first year for the Holley 1945 carbs. They had a lot of problems that year, and were extensively altered over the next several years. By 1978 or so they had them worked out OK, to the degree that the only real problem was very lean jetting to try to squeak the cars past Federal emissions certification tests so that they could be sold new. The problem you're describing sounds like the choke is coming off too quickly. As soon as you step on the gas, the choke opens, the fast-idle cam swings off, and when you take your foot off the gas the throttle plate closes. The engine's too cold to support low idle, so it stalls. The '73+ factory electric chokes are pretty Rube Goldberg and cannot be adjusted. You will save yourself a great deal of aggravation by buying one of the electric choke kits. This, when properly adjusted (it's adjustable!) will likely help you solve the present issue. |
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| Author: | 73dartcustom [ Wed Jun 13, 2007 10:47 pm ] |
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Could it have anything to do with the idle circuit? It only dies after the fast idle cam drops after the choke has completely opened and the car has warmed up. If so where is this and how would I go about fixing it? |
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| Author: | SlantSixDan [ Wed Jun 13, 2007 10:57 pm ] |
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Yes, the problem is probably related to the idle circuit, which is not an electrical circuit, but a series of paths and passageways inside the carburetor that carry fuel and air when the throttle plate is fully or mostly closed. You cannot really access the whole idle circuit, but you can try cleaning it out by blocking the throttle partway open so that the engine will run at a fast idle of about 1600 RPM, removing the idle mixture screw, and spraying carburetor cleaner into the idle mixture screw hole. Replace the idle mixture screw, seat it gently, back it off 2½ turns, then with the engine still idling fast, spray carb cleaner into the one small and one tiny hole visible in the carb throat when you remove the air cleaner. Both of these holes face the sky. Then unblock the throttle, and readjust your idle mixture, procedure here and notes here. |
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| Author: | Sam Powell [ Thu Jun 14, 2007 4:22 am ] |
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Dan's procedure is classic, and will work on most cars, but if things are not all up to snuff, as he suggests is recomended, the engine may not want to idle at 650. I would recommend trying to get it to idle at 850 or 900 if it will not idle at 650. This is not ideal, but might work, and might get you going until you get everything else worked out. Hange with this forum for awhile, and you will pick up on the other things that will make your old gal purr like a kitten once again. Sam |
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| Author: | 73dartcustom [ Fri Jun 15, 2007 9:08 am ] |
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I got the idle circuit cleaned out the best that I could and it actually ran after the fast idle cam dropped. Today will install the distributer cap CH-410X and the M0-3000 rotor (I had been using the original which i found to be in very ruff shape) and work on tuning it from there. What is a good timing set to buy? I was just going to get napa's which was priced around $35 but if there are better out there i would like to do it right. Thanks again for all the info. |
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| Author: | SlantSixDan [ Fri Jun 15, 2007 12:56 pm ] |
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What kind of "timing set" are we talking about? Y'mean a timing light? Good to read that it's at least no longer stalling for you. The cap and rotor will help. Have you bypassed the OSAC valve yet? |
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| Author: | 73dartcustom [ Fri Jun 15, 2007 2:22 pm ] |
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I really don't know, based on "A timing set and new water pump should be strongly considered" in my first post topic after buying the car I went to napa and asked for a price on a "timing set" and was told $35.... I think I did bypass the OSAC valve already and will set the timing and tune the carb after this weekend. I found that the valves were adjusted 10,000 miles ago so I am thinking that that should be ok. Also switched the plugs, wires, water pump, belts, gas tank+sending unit, radiator w/superstat, fuel pump, and hoses.[/u] |
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| Author: | SlantSixDan [ Fri Jun 15, 2007 2:44 pm ] |
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Quote: I really don't know, based on "A timing set and new water pump should be strongly considered" in my first post topic after buying the car I went to napa and asked for a price on a "timing set" and was told $35.... I think
AH! OK, that's a timing chain and sprockets. Can't figure out why you'd need one with just 30k miles on the clock. Yes, your car has a nylon-over-aluminum camshaft sprocket that's less durable than the all-metal ones used in the '60s, but they wear out with miles, not so much with age. You've got a long time before you need to worry about your timing set. Quote: I did bypass the OSAC valve already and will set the timing and tune the carb after this weekend.
Good...Quote: I found that the valves were adjusted 10,000 miles ago so I am thinking that that should be ok.
Perhaps. Not a lot of people know how to do it correctly these days. See valve adjustment procedure. You may want to give them a check.
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| Author: | 73dartcustom [ Fri Jun 15, 2007 4:32 pm ] |
| Post subject: | |
So I just put in the new cap and rotor and now it is running very smooth, night and day difference. However there is now a considerable amount of water coming out of the exhaust and a wet spot on the #6 exhaust. Time for a new head gasket? |
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| Author: | dakight [ Fri Jun 15, 2007 4:37 pm ] |
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A wet spot? I am having trouble picturing what your saying. Condensation from the tail pipe isn't all that unusual so I wouldn't be too hasty with that. |
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| Author: | dakight [ Fri Jun 15, 2007 4:41 pm ] |
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Also, unless your system is filled with stright water, no antifreeze, you would be seeing clouds of white smoke as the glycol burns off. |
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| Author: | 73dartcustom [ Fri Jun 15, 2007 6:24 pm ] |
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It turnes out that there are clouds of white smoke, I just did not mention it because I had not quite set the idle mixture. Now that I have, it persists. |
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| Author: | dakight [ Fri Jun 15, 2007 8:14 pm ] |
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Better run a compression leakdown test but that doesn't sound good. |
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| Author: | 73dartcustom [ Mon Jun 18, 2007 4:19 pm ] |
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I have not yet ordered any of the manuals suggested as of yet and was wondering if anyone would be willing to do a detailed write-up on replacing the headgasket? Possibly a new thread? What would also be good to check while doing this process? Thanks for all the info. |
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