59 dieseling problem
Thread Starter
Heel & Toe
Joined: Jan 2010
Posts: 19
Likes: 0
From: Myrtle Beach SC
59 dieseling problem
Here lately whenever I switch off my 59 it runs for 4-5 seconds after I turn the switch. I have checked the timing, it is fine, the idle is where it should be and the plugs are in good shape. I run 93 octane as it is a 2x4 barrel and I get the fuel from a reputable station, (non-ethanol as well.)
Any ideas on what else to look for would be greatly appreciated!
Any ideas on what else to look for would be greatly appreciated!
Team Owner
Joined: Aug 2007
Posts: 58,061
Likes: 7,146
Army
The octane needed is more related to compression and timing than the number of carbs you have. I run 87 octane all day long in my dual quad 270HP at factory timing.
In addition to the carbon issue:
Could your car be running hotter than usual ? Overheating can cause 'run on'...
What plug are you running ? Maybe the heat range is too high causing dieseling.
You aren't running an MSD ignition system are you ?
Finally, check your idle speed...if its too high crank it down...
In addition to the carbon issue:
Could your car be running hotter than usual ? Overheating can cause 'run on'...
What plug are you running ? Maybe the heat range is too high causing dieseling.
You aren't running an MSD ignition system are you ?
Finally, check your idle speed...if its too high crank it down...
Last edited by Frankie the Fink; Feb 18, 2012 at 05:33 AM.
Thread Starter
Heel & Toe
Joined: Jan 2010
Posts: 19
Likes: 0
From: Myrtle Beach SC
more info on the problem... other than the dieseling at shut off, the car runs fine, it is not running hot, and the problem just started about three weeks ago. Until then there was no problem. The plugs that are in the car have been in for 2.5 years and look fine, only 2000 miles on them.. Idle is set at700- 800, I guess I could back it down some but again it has been set there for years without a problem
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Michael S. Palmer
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
more info on the problem... other than the dieseling at shut off, the car runs fine, it is not running hot, and the problem just started about three weeks ago. Until then there was no problem. The plugs that are in the car have been in for 2.5 years and look fine, only 2000 miles on them.. Idle is set at700- 800, I guess I could back it down some but again it has been set there for years without a problem
Drifting
Joined: Jan 2012
Posts: 1,735
Likes: 289
From: Limerick Pa, Saint James City Fl
i agree
Your throttle plate is too far open at idle, allowing air (and fuel from the transfer slot) to continue to flow when you shut it off. Close it down so only about .020" of the transfer slot is exposed below the throttle plate, and adjust the idle mixture screws for highest steady vacuum. You want it to idle on the round idle mixture orifices, not from the transfer slot.
Drifting
Joined: Jan 2012
Posts: 1,735
Likes: 289
From: Limerick Pa, Saint James City Fl
Here lately whenever I switch off my 59 it runs for 4-5 seconds after I turn the switch. I have checked the timing, it is fine, the idle is where it should be and the plugs are in good shape. I run 93 octane as it is a 2x4 barrel and I get the fuel from a reputable station, (non-ethanol as well.)
Any ideas on what else to look for would be greatly appreciated!
Any ideas on what else to look for would be greatly appreciated!
Thread Starter
Heel & Toe
Joined: Jan 2010
Posts: 19
Likes: 0
From: Myrtle Beach SC
Thanks for checking back. Like a lot of people around here I have come down with a cold that is kicking my butt! I haven't had a chance to get out to the garage to work on the car. Once I get it fixed I'll update the situation. Thanks to all that chimed in!
Le Mans Master
Joined: Feb 2008
Posts: 5,215
Likes: 447
From: NJ Hockey beer league
Check the linkage and pivot points of the throttle shafts for binding. After they sit a while sometimes they can stick a bit. I give a couple of drops of light oil on each of the pivot points (usually happens to my choke) and it frees right up and is fine for a good long while after. Move the linkage points by hand to confirm they are fully closing. . Pilot Dan
Pilot Dan
Thread Starter
Heel & Toe
Joined: Jan 2010
Posts: 19
Likes: 0
From: Myrtle Beach SC
Check the linkage and pivot points of the throttle shafts for binding. After they sit a while sometimes they can stick a bit. I give a couple of drops of light oil on each of the pivot points (usually happens to my choke) and it frees right up and is fine for a good long while after. Move the linkage points by hand to confirm they are fully closing. . Pilot Dan
Pilot Dan