High rpm miss
06-28-2003, 02:23 PM
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High rpm miss
Got a question about a friend's boat.........
'96 454 mag
Engine starts to miss at high rpms after running for awhile ( heating up). Eventually gets to where will only idle...... Not a fuel problem. After it sets for awhile, runs ok for awhile. Defininately sounds like some kind of ignition miss.
Have changed dist. cap, rotor, plugs, wires, coil.....no help.
Ignition module? , bad tach?
Any ideas appreciated.
Thanx, George
'96 454 mag
Engine starts to miss at high rpms after running for awhile ( heating up). Eventually gets to where will only idle...... Not a fuel problem. After it sets for awhile, runs ok for awhile. Defininately sounds like some kind of ignition miss.
Have changed dist. cap, rotor, plugs, wires, coil.....no help.
Ignition module? , bad tach?
Any ideas appreciated.
Thanx, George
06-29-2003, 12:31 AM
#3
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Since all the basics have been replaced, I would guess that the ignition module is getting hot and going bad. Probably not advancing the timing like it should.
06-29-2003, 01:00 AM
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Could be the coil too. They get hot when run for long periods, especially if they are going bad. Will cause a miss.
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06-29-2003, 06:11 AM
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I relocated my ignition module to the transom, just be sure to run a ground to it. Less heat buildup. Mounted to a hot exhaust manifold seems like a bad place for an electronic component.
06-29-2003, 08:39 AM
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The module is the next thing he's gonna swap. I have a spare T-IV , but his was different. It actually has 2 "boxes" bolted next to the distributor that have plugs. One was a GM part, the other was a Nippon!.........T-V?
I tried advancing the timing while running when it started missing, only helped a little. Figured if the "box"was going bad, it was interupting the signal to the dist....??
My thoughts anyway
Thanx for the input
George
I tried advancing the timing while running when it started missing, only helped a little. Figured if the "box"was going bad, it was interupting the signal to the dist....??
My thoughts anyway
Thanx for the input
George
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06-30-2003, 10:40 PM
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I know this might sound stupid, but do you find any moisture in the distributor, is it a marine distributor? I had some problems similiar to mine and it was somehow getting moisture inside and causing it to miss at high rpms. I replaced the distributor with a Billet MSD and no more problems.
07-01-2003, 08:57 PM
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I looked at the dist. right after we shut it down........it was dry. Also checked the "pickup" inside the dist. for cracks, corrosion, etc. .......everything looked new.
Appreciate all the ideas / input.
Gonna try a new module later this week if weather holds, will let ya know what we find.
Thanx, George.
Appreciate all the ideas / input.
Gonna try a new module later this week if weather holds, will let ya know what we find.
Thanx, George.
