Author
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Topic: Its not fuel! cleveland still missing above 4000rpm.
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70coupe Gearhead Posts: 382 From: Toronto,Ontario,Canada Registered: Aug 2000
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posted 10-10-2002 07:38 PM
My fuel pressure seems to be fine but when the rpm reaches 4000rpm or so there is a small miss in the motor. I changed the plugs,wires and complete distributor as I have a spare. Still does it! I run msd,so I checked my grounds and they seem to be good. Any other ideas, I'm going to the track for the weekend tomorrow. Brian------------------ 351c 4v clsd heads 60'1.619 1/8 [email protected] 1/4 [email protected]
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kid vishus Gearhead Posts: 5248 From: middle of NC Registered: Oct 2000
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posted 10-10-2002 08:20 PM
If it's a constant miss over 4000, and it just started happening, I would lean towards the valve springs going sour.
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denny Journeyman Posts: 65 From: Northfield NH USA Registered: Jul 2000
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posted 10-10-2002 10:39 PM
I was thinking the same thing.------------------ D French 67 427 Fairlane(A/SA) 73 Mustang 351c
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MrWesson22 Gearhead Posts: 1212 From: Dacula, GA Registered: Sep 2000
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posted 10-10-2002 11:18 PM
It's a bad carb. Send me yours and I'll be kind enough to swap you mine even.
------------------ Neal 69 Gulfstream Aqua Grande 351C/4sp
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Dusty Kiser Gearhead Posts: 127 From: Bethel,Oh USA Registered: Mar 2002
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posted 10-12-2002 03:59 PM
quote: Originally posted by 70coupe: My fuel pressure seems to be fine but when the rpm reaches 4000rpm or so there is a small miss in the motor. I changed the plugs,wires and complete distributor as I have a spare. Still does it! I run msd,so I checked my grounds and they seem to be good. Any other ideas, I'm going to the track for the weekend tomorrow. Brian
I've probably missed previous info, but I assume you've already run a compression and/or leakdown test and all is good. You've read the plugs and they look good also? You don't specify if it misfires anytime it goes over 4G's or if it's only with no load while sitting in the garage. You might perform a cylinder balance test to see if it's a random miss or if one cylinder is the culprit. Can we assume you've thoroughly inspected the valve train and have no keepers pulling through or shims spit out? Could be a weak spring(s) as Kid says or lobe wiping off the cam. It's a process of elimination. A sharp guy with a scope could tell you what it needs pdq.
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N266fords Gearhead Posts: 1039 From: Spokane ,WA USA Registered: Apr 2003
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posted 07-22-2003 03:45 AM
I dont know if you have found the problem but it could also be a weak ingnition like a coil bad wires.For example if you engine load rise with rpm that is then so does the demand on the electrical load to supply enough juice to light it off and burn it completly. I had a coil go bad once on me and It was a pita to figure out, it ran like a raped ape until 3500 rpms then if my foot was in the wot pos it would fall on its face like i ran out of fuel ,ease up the the gas pedal and it would turn 5500 with no problems at all. I checked the carb fuel presure line filter timing ect.Finaly just swaped the coil and zoom off I went. put the old one back on it back came the problem..Bruce
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