help

rgarvey · 07-19-2011, 07:25 PM

ok car slows down 3 tenths changed trans and converter no change leaked motor down no problems compression also good changed coil and plugs no change valve springs are fine checked power and ground at msd box no problem changed msd box no change. please send me down the right path. vehicle is 340 low compression engine thanks

rgarvey · 07-19-2011, 07:28 PM

also checked fuel pump and pressure and changed fuel no change

Michael Beard · 07-19-2011, 07:46 PM

Brake dragging? Sucked intake gasket? Changed fuel? (I ran out of my Sunoco blue this weekend, bought VP 110 at the track and lost .15!)

Secondaries opening?

Try replacing the diaphragm in the regulator. I've heard of them doing the 'gas can test' just fine, but still not working properly downtrack under a load.

Myron Piatek · 07-19-2011, 09:05 PM

Throttle cable adjustment, opening all the way? Try swapping the whole carb as that could eliminate a few potential possiblities. Bolts tight?

Is it through the whole range, launch (60' & converter flash) to finish (mph)? How much is the weather different between the last good run and when the problem showed up? Anything different with the air filter, filter base, etc.? Same weight?

How old are the plug wires, cap & rotor?
Batteries & alternator putting out good voltage to everything?
Check battery terminals for corrosion.

Distributor leads tight? I had a wire start wiggling out of the plastic connector, shut the motor off and wouldn't restart. But it could cause an intermittant miss down track.

Sounds like it has to be something simple.

rgarvey · 07-19-2011, 09:22 PM

thottle is opening all the way and so is door its slow all the way through down across the ticket doesent miss a beat just feels flat batterys test fine cap rotor brand new wires about a year old i checked dist leads clean and tight and they ohm good

Ed Fernandez · 07-19-2011, 09:44 PM

Checked oil for metal.Might be wearing cam lobes?

Irace007 · 07-19-2011, 11:14 PM

By chance are you running a clutch fan for cooling?

Jim Kaekel · 07-20-2011, 10:03 AM

Check the balancer and ensure that the outer ring hasn't spun on the inner hub. If thats happened, it obviously would show incorrect ignition timing. I got burned on that one many years ago.

John Kelley · 07-20-2011, 02:29 PM

Could it be a bad timing chain ?
Ours slowed down .15 in a week with no changes. Nothoing else seemed unusual until the timing chain broke. When the mess was cleaned up and timing chain replaced it was all back to normal.

rgarvey · 07-20-2011, 05:11 PM

no clutch for cooling fan i just ripped the timing cover off looks fine as far as the cam lobes lash was fine cam looks like new also has shubecks checking dist leads now

07-19-2011, 07:25 PM	#1
rgarvey Junior Member Join Date: Jun 2007 Posts: 58 Likes: 0 Liked 0 Times in 0 Posts	help ok car slows down 3 tenths changed trans and converter no change leaked motor down no problems compression also good changed coil and plugs no change valve springs are fine checked power and ground at msd box no problem changed msd box no change. please send me down the right path. vehicle is 340 low compression engine thanks

07-19-2011, 07:28 PM	#2
rgarvey Junior Member Join Date: Jun 2007 Posts: 58 Likes: 0 Liked 0 Times in 0 Posts	Re: help also checked fuel pump and pressure and changed fuel no change

07-19-2011, 07:46 PM	#3
Michael Beard VIP Member Join Date: Sep 2002 Location: Columbus, OH Posts: 4,060 Likes: 0 Liked 13 Times in 9 Posts	Re: help Brake dragging? Sucked intake gasket? Changed fuel? (I ran out of my Sunoco blue this weekend, bought VP 110 at the track and lost .15!) Secondaries opening? Try replacing the diaphragm in the regulator. I've heard of them doing the 'gas can test' just fine, but still not working properly downtrack under a load. __________________ Michael Beard - NHRA/IHRA 3216 S/SS

07-19-2011, 09:05 PM	#4
Myron Piatek VIP Member Join Date: Nov 2001 Location: Florida Posts: 1,542 Likes: 34 Liked 138 Times in 51 Posts	Re: help Throttle cable adjustment, opening all the way? Try swapping the whole carb as that could eliminate a few potential possiblities. Bolts tight? Is it through the whole range, launch (60' & converter flash) to finish (mph)? How much is the weather different between the last good run and when the problem showed up? Anything different with the air filter, filter base, etc.? Same weight? How old are the plug wires, cap & rotor? Batteries & alternator putting out good voltage to everything? Check battery terminals for corrosion. Distributor leads tight? I had a wire start wiggling out of the plastic connector, shut the motor off and wouldn't restart. But it could cause an intermittant miss down track. Sounds like it has to be something simple.

07-19-2011, 09:22 PM	#5
rgarvey Junior Member Join Date: Jun 2007 Posts: 58 Likes: 0 Liked 0 Times in 0 Posts	Re: help thottle is opening all the way and so is door its slow all the way through down across the ticket doesent miss a beat just feels flat batterys test fine cap rotor brand new wires about a year old i checked dist leads clean and tight and they ohm good Last edited by rgarvey; 07-19-2011 at 09:24 PM. Reason: more info

07-19-2011, 09:44 PM	#6
Ed Fernandez Veteran Member Join Date: Nov 2001 Location: NOO JOISEY nexta NOO YAWK Posts: 5,879 Likes: 38 Liked 100 Times in 45 Posts	Re: help Checked oil for metal.Might be wearing cam lobes? __________________ Former NHRA #1945 Former IHRA #1945 T/SA

07-19-2011, 11:14 PM	#7
Irace007 Member Join Date: Apr 2011 Location: Forest Lk Minn. Posts: 103 Likes: 535 Liked 17 Times in 12 Posts	Re: help By chance are you running a clutch fan for cooling?

07-20-2011, 10:03 AM	#8
Jim Kaekel VIP Member Join Date: Jul 2002 Location: Michigan Posts: 1,227 Likes: 133 Liked 531 Times in 108 Posts	Re: help Check the balancer and ensure that the outer ring hasn't spun on the inner hub. If thats happened, it obviously would show incorrect ignition timing. I got burned on that one many years ago. __________________ Jim Kaekel 3836 STK

07-20-2011, 02:29 PM	#9
John Kelley Senior Member Join Date: Feb 2002 Location: Tightwad,TEXAS Posts: 911 Likes: 6 Liked 3 Times in 3 Posts	Re: help Could it be a bad timing chain ? Ours slowed down .15 in a week with no changes. Nothoing else seemed unusual until the timing chain broke. When the mess was cleaned up and timing chain replaced it was all back to normal.

07-20-2011, 05:11 PM	#10
rgarvey Junior Member Join Date: Jun 2007 Posts: 58 Likes: 0 Liked 0 Times in 0 Posts	Re: help no clutch for cooling fan i just ripped the timing cover off looks fine as far as the cam lobes lash was fine cam looks like new also has shubecks checking dist leads now