Rpm drop
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Rpm drop
1984 351w with a c4 transmission, have to raise the idle rpm to 1000 to keep the engine from stalling,the rpms drop to 700 when put in drive. 20"vacuum ,compression 145 to 155,engine runs good.Have had mechanics say ,you may have to run it this way.torque converter problems?????? Any help would be appreciated!!!
Last edited by Larry5501; Dec 29, 2017 at 05:14 PM. Reason: To clarify statement
Lead Driver
Joined: Jul 2011
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From: On the Edge of the Desert
From what you've described, nothing is wrong...
other than the stalling out part. Let's Go into more detail on that. Something probably just needs to be adjusted.
When does it stall?
other than the stalling out part. Let's Go into more detail on that. Something probably just needs to be adjusted.
When does it stall?
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The engine stalled when transmission was put in drive.Had to raise the idle to 1000 to keep the engine running when the truck was stopped.never had to run the idle rpms that high on any other ford f100 I have owned,but this is the first f100 with an automatic.
Lead Driver
Joined: Jul 2011
Posts: 8,678
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From: On the Edge of the Desert
The engine should idle at about 700 rpm in neutral, and drop to about 500 in drive.
If that's not happening like that, then you have other issues. My first guess would be retarded ignition timing.
If that's not happening like that, then you have other issues. My first guess would be retarded ignition timing.
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O
On the timing,mechanics have checked the timing.The timeing cover has not been removed for a visual check,but have rotated the crank while observing the rotor.The slack in the timing chain seems to be little,about 2 degrees of crank rotation and the rotor button begins to turn.Set the timeing at 12 degrees advance at idle vac hose off of the distributor and plugged, no help there.Set the timing with a vacuum gage for max vacuum,hopeing to eliminate harmonic damper slippage if it existed,no help there.adjusted the mixture on the new Holley carb,no help there.Checked top dead center on the number one cylinder,both valves are closed with no pressure on the push rods.no help there.Checked compression 145 psi to 155psi. Have not done a leak down test on the cylinders.the distributor is an accel dist.Checked the vacuum advance mechanism, it's not binding and is connected to the upper port on the Holley.New gasket on the intake manifold.Any help would be appreciated!I
Cargo Master
Joined: May 2015
Posts: 2,350
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From: Garland, Tx
20” of vacuum is a bit high for setting timing with a vacuum gauge. 18”is optimal, 15”-17” is acceptable. What carb are you running?
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