Odd idle
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Cross-Country
Joined: Aug 2002
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Odd idle
Hi there I'm trying to figure out what causing the odd idle on my 71 F-250 with the 360.
It's has a new distributor and rebuilt carb and new timing chain. I saw a thread that mentioned the springs in the distributor can break.
any thoughts? The odd idle is it will run but not accelerate then all of sudden it runs just fine.
Thanks.
It's has a new distributor and rebuilt carb and new timing chain. I saw a thread that mentioned the springs in the distributor can break.
any thoughts? The odd idle is it will run but not accelerate then all of sudden it runs just fine.
Thanks.
Lead Driver
Joined: Jul 2011
Posts: 8,679
Likes: 191
From: On the Edge of the Desert
Can you give us more detail as to when it does this?
Will the engine rev up in neutral? Does it only bog down when you're trying to drive?
And Just because parts are new, doesn't mean that they are good or adjusted properly.
Will the engine rev up in neutral? Does it only bog down when you're trying to drive?
And Just because parts are new, doesn't mean that they are good or adjusted properly.
Post Fiend
Joined: Apr 2002
Posts: 19,311
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From: Waterloo, Iowa
Process of elimination: Verify "0" TDC mark on the damper is indexed correctly. This is a very common defect. Sounds like a lot of parts were replaced, was this checked? Makes tuning/timing problematic due to faulty assumptions. Not unusual to see ignition timing 10° or 20° off from where it should be when this happens. Needs a new damper if this is the case. A piston stop tool is the best way. Even new aftermarket dampers can be off by a few degrees. Marking or verifying the exact TDC is important for baseline.
An easy check if there are questions about the distributor; run it up in neutral with a timing light put it through the paces from idle to 3000+ RPM (be VERY careful of the radiator fan) and verify the mechanical advance is working smoothly up and down the RPM range and doesn't stick. Make this test with the vacuum advance port disconnected and plugged. It should top out around 36° BTDC.
An easy check if there are questions about the distributor; run it up in neutral with a timing light put it through the paces from idle to 3000+ RPM (be VERY careful of the radiator fan) and verify the mechanical advance is working smoothly up and down the RPM range and doesn't stick. Make this test with the vacuum advance port disconnected and plugged. It should top out around 36° BTDC.
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Post Fiend
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Thread Starter
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Cross-Country
Joined: Aug 2002
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Odd idle
I'm replacing the distributor and see what happens.
it's under warranty so no more $ spent and one more thing I eliminated as a cause.
it's under warranty so no more $ spent and one more thing I eliminated as a cause.
Last edited by reddogg94602; Jan 25, 2019 at 06:38 PM. Reason: More info
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