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 Post subject: Getting run on bad
PostPosted: Mon Nov 26, 2007 5:01 pm 
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Turbo EFI
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Location: Sacramento, CA
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I've always had a little bit of run on because my engine idles a bit too fast. It used to shut off fine or turn over once or twice when i'd shut the engine off. Then I took it to this shop that corrected some vacuum leaks and adjusted the valves. Well now (even though its idling slower than it originally did) the run on is terrible. I shut the key off and the motor turns over between 3-7 times and then "wheezes" out when it dies. Could this be because they adjusted the valves wrong? It's never ran on this long and it's never made this air wheezing sound when dying until I took it to that shop.

It also came back with a bad hesitation. I can get the run on to kind of die down a little bit by slowing the idle down. But then this causes a hesitation when im on the gas. When its fully warmed up I can still feel the hesitation but the car won't die. When the car is cold the car can easily die when I get on the gas. The only way to stop it is to kind of vibrate my foot on the gas until it stops hesitating and goes. Could this all be because of the valve adjustment? I don't see how fixing vacuum leaks could cause this.

Oh and they also changed the distributor because of a loose shaft. The car is timed at 6 BTDC.


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 Post subject:
PostPosted: Mon Nov 26, 2007 7:13 pm 
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What-all, exactly, did this shop do? Sounds like they probably did more than just adjust the valves and "correct some vacuum leaks" (what exactly did they do?), and/or sounds like they might not have adjusted the valves correctly.

What kind of shop was this? A general garage, maybe one not so familiar with older cars...?

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 Post subject:
PostPosted: Mon Nov 26, 2007 8:01 pm 
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Supercharged
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Location: Black Diamond, WA
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My engine before the rebuild used to run on especially when hot. That can be from carbon build up on the pistons, head and valves.

The gentlest fix is to run some Seafoam through it per the instructions on the bottle. If it is really bad, you may have to drip a cup of water in the carb while it is idling. I hooked up water injection on my new engine just to keep it cleaned out. I don't use it all the time, just once a month is all it takes. The plugs and chambers stay nice an clean that way. The results are a very crisp idle and no run on.......That should perk it up if everything else is up to SL6 Dan's standards.

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 Post subject:
PostPosted: Mon Nov 26, 2007 9:06 pm 
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Turbo EFI
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Joined: Thu Nov 11, 2004 4:33 pm
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Location: Sacramento, CA
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Ok im gonna try and make sense of what this paper says.

Looks like they changed out the distributor because there was excessive shaft movement side to side. They adjusted the timing to TDC (which I changed back to 6 BTDC) and set the dwell between 41-46.

Now on the paper it says "All valves were tight. Adjust valves. 70 intake / 20 exhaust. Remove top of carb for inspection. Clean inside and blow out all passages. Apply thread sealer to carb hold down bolts. Replace EGR gasket." (blockoff gasket)

The shop seemed very reputable. They've been around for over 40 years and the guy I talked to even owned a Dart with a slant six and seemed like he knew what he was doing. This engine only has about 3000 miles on the rebuild. All I wanted was the throttle shaft on the carb rebushed and they did all this crap.


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 Post subject:
PostPosted: Mon Nov 26, 2007 9:57 pm 
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EFI Slant 6

Joined: Thu Sep 14, 2006 7:54 pm
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Adjust valves. 70 intake / 20 exhaust. That has to be a typo.

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 Post subject:
PostPosted: Mon Nov 26, 2007 10:11 pm 
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Supercharged

Joined: Thu May 12, 2005 11:50 pm
Posts: 6291
Location: So California
Car Model: 64 Plymouth Valiant
Quote:
Adjust valves. 70 intake / 20 exhaust. That has to be a typo.
probably 10/20

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 Post subject:
PostPosted: Tue Nov 27, 2007 3:51 am 
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4 BBL ''Hyper-Pak''
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Joined: Fri Nov 09, 2007 12:54 pm
Posts: 49
Location: centerport , ny
Car Model: 65 Valiant station wagon ,66 Valiant convertible,
What I do when I have this problem is to run a vacuum line into the car where I have a jar of water.I pinch off the vacuum line to seal it and have the open end in the water.I take the car out on the interstate and get it up to speed nice & warm and open up that hose for a few seconds and let the motor suck some water at speed.It blows the carbon right out and this usually fixes that.The key is to do this when the motor is good and hot and at hiway speed 60 mph or more for short bursts don't just let the motor drink a quart of water.A squeeze type clamp works well to pinch the line.An old school bus mechanic taught me this trick about 30 years ago. School buses get carboned up real bad and he found that this method was the best and easiest way to deal with it.


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 Post subject:
PostPosted: Tue Nov 27, 2007 7:02 am 
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Location: North America
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Quote:
Looks like they changed out the distributor
That could be an important clue. If they installed a "remanufactured" distributor, there's no telling what advance curves you've now got. They are likely very far off what you started with.
Quote:
Now on the paper it says "All valves were tight. Adjust valves. 70 intake / 20 exhaust.
As others have noted, probably "10 intake / 20 exhaust", but did they do this adjustment with the engine hot, or with it cold? If cold, they'll be too tight when the engine's warmed up.
Quote:
All I wanted was the throttle shaft on the carb rebushed and they did all this crap.
Did they actually rebush the throttle shaft? How careful were they to get the throttle plates exactly, precisely back into their original position? There's a lot of play in the throttle plate-to-shaft fit, so the location of the shaft must be scribed or otherwise marked on the plate and the location of the plate must be scribed or otherwise marked in the throttle bore, before disassembly. This has implications for the idle transfer port, spark advance port, and other operating characteristics of the carb which directly affect engine operation.

There should not be enough carbon to cause the run-on you're experiencing after only 3,000 miles, unless the engine has been running so rich that clouds of black smoke have been chuffing out the tailpipe and spark plugs have been lasting a week or so.

As far as the shop's competence, I'm not convinced. A shop that lets a car go out with more running problems than it came in with doesn't seem so reputable to me.

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 Post subject:
PostPosted: Tue Nov 27, 2007 4:26 pm 
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Turbo EFI
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Joined: Thu Nov 11, 2004 4:33 pm
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Location: Sacramento, CA
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Yeah it's been running lean, not rich since I put on this super six about 2000 miles ago. I don't see how carbon could be a problem. What kind of problems arise when the valves are too tight? It looks like im gonna have to go ahead and try to adjust them myself. The 70/20 thing is what the paper says, so im sure it means 10/20 like you guys said. The distributor that was in it was already a remanufactured job, so it's not like ive really taken much of a step down with it.

I'm gonna head down to this shop on Saturday and talk to them about it. I don't see anywhere on this paper that mentions rebushing the throttle shaft.

What are the usual problems when it comes to getting excessive run on and hesitation when getting on the throttle? I know its getting enough gas.


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 Post subject: some ideas
PostPosted: Tue Nov 27, 2007 9:37 pm 
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EFI Slant 6
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Joined: Tue Sep 05, 2006 9:01 pm
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If you are lean, it could be preignition and overheating causing your problems. Maybe try a little less timing in the meantime until you can get more fuel in there- if you are running hot there could be red hot stuff in the chambers lighting off your mixture early making your heat problem worse?

Also, if you have an auto trans you can turn the car off in Drive and the resistance of the converter might stop it from dieseling- some advise I picked up from SS Dan. Then put it in park and get your key.

Good luck

radar

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 Post subject: some ideas
PostPosted: Tue Nov 27, 2007 9:38 pm 
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EFI Slant 6
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Joined: Tue Sep 05, 2006 9:01 pm
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If you are lean, it could be preignition and overheating causing your problems. Maybe try a little less timing in the meantime until you can get more fuel in there- if you are running hot there could be red hot stuff in the chambers lighting off your mixture early making your heat problem worse?

Also, if you have an auto trans you can turn the car off in Drive and the resistance of the converter might stop it from dieseling- some advise I picked up from SS Dan. Then put it in park and get your key.

Good luck

radar

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 Post subject:
PostPosted: Wed Nov 28, 2007 1:45 am 
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Turbo Slant 6

Joined: Thu Jul 13, 2006 8:05 pm
Posts: 770
Car Model:
Exactly what is the engine idling at now?

It sounds like the carb is setup to lean right off. Plus I am guessing that the accellerator pump is not ajusted and or working right. To lean, and the accellerator pump can cause the hesitation & cold running problems. I find all the /6's that I get have this problem. You can try turning the idle mixture screws out farther to see if that helps richin it up. They only add fuel for the idle curcuit, but it draws off the idle curcuit even when you are running the peddle open so it adds fuel to go with the main. I had to change the jets to bigger ones in mine. It cam with 45 jets and I have had to raise them to number 58 jets. In this cold weather I have had to raise them even farther to 60's to keep it running good in this cold weather. The fuel milage incressed by a whole lot when I went to the 58 jets. But it has droped a little sense I put the 60's in and have to deal with this cold weather. But it is still getting 18mph, although it was getting 21. With the 58 jets when it drops below 50* it would hesitate unless I let it warm for a long time. With the 60's it runs good even if I dont let it warm. This is all on the Holley one barrel.


What spark plugs are you running, if they are to hot a heat range it can cause this run on. Also if the engine has a lot of compression and you are running to cheap a gas for it this can cause it. Try putting premium in it to see if it helps. If it does then you can probably tune for the premium & get better fuel milage to make up for the extra cost ( it can stand more base timing with the premium).


Do make sure your valves are right, and you dont have any other vacume leaks. I had problems with my valves not liking to run with the exhaust set at 10. I started ajusting them to 15 lash and the car ran much better and was not much louder in the valve train. I did end up running them at 13 lash after some expeiramenting. The intake I still run at 20 lash with no problems.


Jess


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 Post subject:
PostPosted: Fri Dec 21, 2007 5:55 pm 
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Turbo EFI
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Joined: Thu Nov 11, 2004 4:33 pm
Posts: 1004
Location: Sacramento, CA
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I put on a NOS Carter BBD and it ran better for a few weeks with less run on but still did it from time to time. Now im back to what appears to be the same old problem. The engine idles at 900-1000 and then drops to about 600 when put in gear. When its in park, the idle sounds nice and smooth. When its in drive, it chugs and sounds like it wants to die. Just like the old remanufactured carb, this NOS carb has to have the mixture screws turned out 4 to 5 turns to pull a normal vacuum (remanufactured carb was only pulling about 16, while the NOS carb pulls 20 on the guage). When I turn the mixture screws in to their normal 2-3 turns, the vacuum reads real low (13-15) and the engine runs rough even with the idle screw turned in to keep the thing running. I've checked numerous times and I have no air leaks around the intake or carb. What else could be the problem? I'll idle the thing up and it'll run semi smooth. Then I'll take it on the freeway and run 65-75mph for 10 or so minutes. When I get off the freeway its like everything I just did has been undone and the car runs really rough when off the gas and wants to die unless I hold the gas down with my foot on the brake.

Also when watching the timing, is the mark supposed to move when you disconnect the hose that leads down to the distributor? I know you're supposed to unhook it and plug it when doing timing, but I see no movement at all in the mark when this hose is disconnected, and disconnected and plugged. I don't know if thats normal or if that means the pod is messed up? I just can't figure out why this thing won't run smooth with either carb. It's like theres this huge unknown air leak somewhere that I can't access.


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 Post subject:
PostPosted: Fri Dec 21, 2007 6:07 pm 
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Supercharged
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Joined: Thu Jan 27, 2005 8:32 pm
Posts: 7834
Location: Portland-ish
Car Model: Fiat 500e
Is your engine in good mechanical condition? Did the car run well before the Super Six swap? Is the manifold cracked and leaking exhaust into the intake?

Get the engine hot, pull all the plugs and run a compression test. I have a feeling the engine may be tired, but it's just a guess.

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 Post subject:
PostPosted: Fri Dec 21, 2007 6:24 pm 
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Supercharged
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Joined: Wed Oct 12, 2005 9:00 pm
Posts: 2885
Location: kankakee IL
Car Model: 80 volare, 78 fury 2 dr, 85 D150
1) engine only 3000 miles on rebuild. Shouldnt yet be tired.
2) NOS Carter carb; If it IS truly NOS and not a "new" reman why would it need rebushed already?
3) I take it that you are running points since there was talk of setting dwell. By changing timing you also change dwell.


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