1967 - 1972 F-100 & Larger F-Series Trucks Discuss the Bumpsides Ford Truck

Low Idle & Dying

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Old 07-24-2014, 12:29 AM
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Low Idle & Dying

Alright so some may know me about my radiator deal; I bought a used radiator today, haven't installed yet.

But what I'm on here about now is that my truck has a suuuuper low idle and likes to die unless I'm giving some throttle.

Some things; PO ziptied manual choke wide open. Also, seems to me that this started happening after I tightened my alternator belts. Just some facts to think about. I was thinking about my coolant level, too. I topped off completely right before my drive and the low idle issue seemed to be more prominent; bad water pump?

Anyways, I'm going to check my timing asap, to make sure it's 6 degrees BTDC. If I feel courageous I'll set it to 10. Whatever the case, I'm going to get timing out of the question and see if that's my issue.

Then I'll be testing my alternator...really don't think it's faulty but I gotta know for sure. After that, I'll tackle the carb. Hopefully cutting the zip tie doesn't open a whole 'bother can o' worms of trouble. But maybe my issue is that the choke wide open is making it too lean, who knows.

My headlights dim almost completely off when the truck is about to die at really low idle, what would that mean, or be caused by?

I can only do all of this if I have time at work, which I probably won't soon, but I'll keep this updated with what I find. In the meantime I'd appreciate input from your own experiences. Maybe my timing chain jumped a tooth?
 
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Old 07-24-2014, 12:49 AM
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I would set timing at 10, and try to re adjust the carb. Set mixture screws to 2 turns rich. That should make any engine run. Set idle speed to 650-700.

Headlights dimming is a direct result of the alternator not spinning fast enough to produce the necessary voltage.

If the water pump shelled out, then it could possibly creating a huge drag on the engine.

Try running without the belt(s) for a minute. If it runs normal start looking for the drag.
 
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Old 07-24-2014, 12:56 AM
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I would set timing at 10, and try to re adjust the carb. Set mixture screws to 2 turns rich. That should make any engine run. Set idle speed to 650-700.

Headlights dimming is a direct result of the alternator not spinning fast enough to produce the necessary voltage.

If the water pump shelled out, then it could possibly creating a huge drag on the engine.

Try running without the belt(s) for a minute. If it runs normal start looking for the drag.
 
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Old 07-24-2014, 01:15 AM
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Originally Posted by 351Cleveland C4
I would set timing at 10, and try to re adjust the carb. Set mixture screws to 2 turns rich. That should make any engine run. Set idle speed to 650-700.

Headlights dimming is a direct result of the alternator not spinning fast enough to produce the necessary voltage.

If the water pump shelled out, then it could possibly creating a huge drag on the engine.

Try running without the belt(s) for a minute. If it runs normal start looking for the drag.
Okay, I will try 10 and that idle rpm.

About the alternator: it ran fine when the belts were taught but not tight; now they're tight. Would the belts being tighter make it difficult for it to turn?

Also, what exactly does shelled out mean?

Thank you for your help, I'll be testing these things
 
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Old 07-24-2014, 01:18 AM
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Shelled out usually refers to a bearing going out or major mechanical failure.

If your alternator bearing was going bad that could also do it. But I would think the belt would slip first.
 
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Old 07-24-2014, 06:46 AM
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Sounds more like a vacuum leak. Do you have power brakes? Check the hose from the manifold to the booster. That's where my leak was, right at the manifold elbow.
And I always rebuild the carb. Just a good starting point. Use the Ford kit.
 
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Old 07-24-2014, 08:06 AM
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Yeah I've known for a while that my booster hose is old and a little leaky, but not too bad. I remember it being difficult to find a replacement a long time ago for some reason.

And yeah I really want to rebuild the carb. I was planning on getting the kit from holley, but what's this Ford kit you mentioned? I have a Holley 2300
 
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Old 07-24-2014, 08:20 AM
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When setting the timing, which end of the marks to you count 6 or 10 from? I'm only confused because it starts at ATC 0, goes to 10, 20, and then 30 BTC and then it says B2 after BTC.

Right now I'm going 10 marks after ATC. Is that correct for 10 BTDC?
 
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Old 07-24-2014, 09:35 AM
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My bad, I thought you had a 2100. Cap off the booster port at the intake manifold and see if your idle problem goes away. I simply got 3' of the correct size vacuum hose to swap out the old line. And two band clamps of the right size. Don't tighten too much on the booster check valve side or you will have to replace that too. Mine really stumbled until I replaced that line.
 
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Old 07-24-2014, 09:48 AM
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Okay, thank you!
 
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Old 07-24-2014, 10:48 AM
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Originally Posted by carchub
When setting the timing, which end of the marks to you count 6 or 10 from? I'm only confused because it starts at ATC 0, goes to 10, 20, and then 30 BTC and then it says B2 after BTC. Right now I'm going 10 marks after ATC. Is that correct for 10 BTDC?
No, you want to go the other way. As the engine is turning, it should fire before the marks hit TDC.
 
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Old 07-24-2014, 10:56 AM
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2x on vacuum leaks. Also check for a bad dizzy vacuum advance before changing the timing & messing with the carb adjustments..
Orich
 
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Old 07-24-2014, 01:52 PM
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Sounds good. So I should make my mark where it says 20?
 
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Old 07-24-2014, 03:06 PM
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Depending on what style balancer and tab you have.

If the balancer is marked with numbers or the tab is marked with numbers. Either way you want the 10btdc to line up with the mark/tab.
 
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Old 07-24-2014, 04:23 PM
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The marks are on the balancer, and look something like


ATC 0 / / / / / / / / / 10 / / / / / / / / / 20 / / / / / / / / / 30 BTC

I thought I'd be aiming for the 10, but if it needs to be on the BTC side then I was saying I'd aim for the 20. Still confused by the balancer, I don't know why ATC is written at 0 degrees before top dead center
 


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