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 Post subject: Tuning?
PostPosted: Sun Nov 22, 2009 2:22 pm 
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Turbo Slant 6
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Location: Ooltewah, Tennessee
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My '65 Valiant (standard equipment) sat for a year while I was putting in an A833 OD. I don't remember how it was doing before that, but I put in new points and plugs and set the timing and choke.

As long as I'm accelerating (not wildly) it runs smooth as glass. When I reach speed and ease off it starts running rough - random missing. I don't even know where to start. Suggestions?

RK


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 Post subject:
PostPosted: Sun Nov 22, 2009 3:25 pm 
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Supercharged
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Sounds like a fuel problem. What is floating around in the fuel bowl? Water? old gas? You may want to take peak and see what is in there. If you have a 1920 Holley on yours you can cut down a red plastic Folger's coffee can to slide under the bowl to catch the old fuel and debris. It is amazing what you find, like chunks of old rubber fuel line......the new fuel really does a number on old rubber.
As you replace the fuel lines, use fuel injection hose 30R9.

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG


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 Post subject:
PostPosted: Sun Nov 22, 2009 4:20 pm 
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Disconnect the vacuum line to the distributer, and plug it. Now do a road test. If that cures the problem, you might have too much advance, or the points not set correctly. Set the points with a dwell meter, and then reset the timing. If that doesn't cure the problem, check the carb.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
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 Post subject: Dashpot...
PostPosted: Sun Nov 22, 2009 7:16 pm 
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Location: Salem, OR
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Does your carb have a dashpot? It's a little vaccuum solenoid for manual trannies that hold the throttle plates open and slowly closes them when you let off the gas... A couple of situations can be occurring here:

1) The plates are closed enough to be in the transition slot and not have the main metering one line...if you have enough rpm and advance going and you let off, you may not have enough gas to cover the advance/load/ and minimal gas the idle/transition circuit gives (retuning, richening the idle/transition circuit... or a hihg rear gear ratio that will put your "cruise" rpm at the speed you are trying to keep up with.

2) Check by driving with a vacc. gauge hooked to a vacc. source under the throttle plates or worst case scenario off the #6 runner.... when you let off the gas if the vacc. is high, and load is high it will starve the engine out of gas... reading the plugs or watching an O2 sensor will allow you to see if you have a "lean out"...which can be a combination of vacc. advance (too much at that moment), and not enough gas (it is lighting the fire early and you might be "shooting ducks", get a rough feel from the engine....)

Either way you need to find out which way it goes and rememdy it before a piston top gets too hot or a plug gets melted.

Good Luck,

-D.Idiot


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 Post subject:
PostPosted: Sun Nov 22, 2009 9:12 pm 
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Turbo Slant 6
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Location: Ooltewah, Tennessee
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Quote:
What is floating around in the fuel bowl?
I'll check it out.

Thanks


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 Post subject:
PostPosted: Sun Nov 22, 2009 9:14 pm 
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Turbo Slant 6
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Location: Ooltewah, Tennessee
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Quote:
Disconnect the vacuum line to the distributer, and plug it. Now do a road test. If that cures the problem, you might have too much advance, or the points not set correctly. Set the points with a dwell meter, and then reset the timing. If that doesn't cure the problem, check the carb.
I love how-to's!

Thanks


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 Post subject: Re: Dashpot...
PostPosted: Sun Nov 22, 2009 9:22 pm 
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Turbo Slant 6
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Joined: Tue May 02, 2006 12:16 am
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Location: Ooltewah, Tennessee
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Quote:
Does your carb have a dashpot? It's a little vaccuum solenoid for manual trannies that hold the throttle plates open and slowly closes them when you let off the gas... A couple of situations can be occurring here:

1) The plates are closed enough to be in the transition slot and not have the main metering one line...if you have enough rpm and advance going and you let off, you may not have enough gas to cover the advance/load/ and minimal gas the idle/transition circuit gives (retuning, richening the idle/transition circuit... or a hihg rear gear ratio that will put your "cruise" rpm at the speed you are trying to keep up with.

2) Check by driving with a vacc. gauge hooked to a vacc. source under the throttle plates or worst case scenario off the #6 runner.... when you let off the gas if the vacc. is high, and load is high it will starve the engine out of gas... reading the plugs or watching an O2 sensor will allow you to see if you have a "lean out"...which can be a combination of vacc. advance (too much at that moment), and not enough gas (it is lighting the fire early and you might be "shooting ducks", get a rough feel from the engine....)

Either way you need to find out which way it goes and rememdy it before a piston top gets too hot or a plug gets melted.

Good Luck,

-D.Idiot
Thanks. I'm going to try reading this one after I get some sleep. I _may_ be able to grasp it then. :shock:

RK


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 Post subject:
PostPosted: Tue Nov 24, 2009 2:30 pm 
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Turbo Slant 6
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Joined: Tue May 02, 2006 12:16 am
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Location: Ooltewah, Tennessee
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Quote:
Sounds like a fuel problem. What is floating around in the fuel bowl? Water? old gas? You may want to take peak and see what is in there. If you have a 1920 Holley on yours you can cut down a red plastic Folger's coffee can to slide under the bowl to catch the old fuel and debris. It is amazing what you find, like chunks of old rubber fuel line......the new fuel really does a number on old rubber.
As you replace the fuel lines, use fuel injection hose 30R9.
The carb is Carter BBS. I found over an eighth of an inch of extremely fine sediment settled and hardened in the bottoms of the float chamber.

I got into it today after having a hard time starting and finding gas all over the top of the manifold. ALL the hold down nolts and screws had worked a little loose. When I stopped at home I checked with a light and gas was bubbling out around the throttle shaft! I tightened the screws and bolts and now no more gas all over. But it was still trying to kill almost as bad as it did on the road today. I thought sinking float.

But the float is dry and the gas level stops just below the gas inlet needle. That looks about right at a strong 3/8 inch below the top of the bowl, but is there some setting to use other than what came with the carb kit a couple years ago?

It may be a fluke about the loose bolts. It may be that the rest of the problem is electrical.

Anybody got further ideas?

RK


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 Post subject:
PostPosted: Wed Nov 25, 2009 12:31 pm 
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Turbo EFI
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Location: Troy, Texas
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Loose base gasket and worn shaft bushings... hmmm. Vacuum leaks wreak havoc on how they drive.

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Ignorance is not knowing any better.
Stupidity is knowing, yet doing it anyway.


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 Post subject:
PostPosted: Wed Nov 25, 2009 1:22 pm 
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Supercharged
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Joined: Mon Jan 15, 2007 5:05 pm
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Location: Black Diamond, WA
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Ross,

Under steady acceleration your getting a richer mix, and when you back off it is going lean. Any kind of a vacuum leak will up set the balance of the mixture and make it run rough. If it feels good under acceleration I wouldn't think it is electrical. Another item to check would be to test your vacuum advance on the distributor to see if it is leaking.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG


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 Post subject:
PostPosted: Wed Nov 25, 2009 9:35 pm 
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Turbo Slant 6
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Joined: Tue May 02, 2006 12:16 am
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Location: Ooltewah, Tennessee
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Quote:
Loose base gasket and worn shaft bushings... hmmm. Vacuum leaks wreak havoc on how they drive.
Thanks, but why would I be getting liquid gasoline bubbling out around the shaft for a minute or more after shutting off the engine?


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 Post subject:
PostPosted: Thu Nov 26, 2009 5:19 am 
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Supercharged
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Joined: Mon Sep 26, 2005 5:09 pm
Posts: 2946
Location: Gilbert, Arizona
Car Model: 1962 Plymouth Valiant Signet
Somehow you're getting raw fuel spilling onto the throttle plate while it's closed; some of it seeps out past the throttle shaft. Perhaps a leaky needle and seat. It sounds like the carb needs to be rebuilt and the throttle shaft bushed. You also need to address the source of the sediment. If the car sat for an extended period with fuel in the tank it could well have a rusty fuel tank.

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 Post subject:
PostPosted: Thu Nov 26, 2009 9:33 am 
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Supercharged
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Joined: Mon Jan 15, 2007 5:05 pm
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Location: Black Diamond, WA
Car Model:
Ross,
Quote:
Thanks, but why would I be getting liquid gasoline bubbling out around the shaft for a minute or more after shutting off the engine?
The needle and seat aren't sealing against the pressure in the fuel line. The metal fuel line gets hot and boils the fuel causing it to expand. If there is some fine muck or rusty particles on the seat, it will not seal off the expanding fuel. After a few minutes the carb starts to percolate like a coffee pot.

Dan's fuel line mod helps to keep the fuel from boiling. It may take some pressure of the needle and seat after shut off. You need a really good filter down to the 2 micron level to filter out the debris and a new needle and seat. Your fuel pump and line back to the tank and the tank itself are probably contaminated. On mine the inside of the metal fuel line was rusting. A good filter will help capture the small particles and get you buy until your able to clean or replace your fuel system.

_________________
Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG


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 Post subject:
PostPosted: Sun Nov 29, 2009 4:54 am 
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TBI Slant 6

Joined: Wed Feb 18, 2004 10:35 am
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edit


Last edited by Kevin Johnson on Sat Jan 09, 2010 12:57 am, edited 1 time in total.

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 Post subject:
PostPosted: Sun Nov 29, 2009 7:30 pm 
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Turbo Slant 6
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Location: Ooltewah, Tennessee
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Quote:
A proportion (most?) of the sediment is likely to be fuel additives that drop out of solution as the car sits for an extended period of time and the fuel ages and evaporates. These can be extremely difficult nigh impossible to resolubalize so they must be cleaned out manually.
Makes sense to me. It was really, really fine and almost chocolate colored. It was pretty hard too and I dug it out with a stick. I could barely dig it with a finger nail.


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