Am I running lean???
Thread Starter
Racer
Joined: Nov 2000
Posts: 473
Likes: 0
From: Centreville, VA USA
Am I running lean???
Folks,
I have an interesting new problem. After I have been driving for a while if I am really light on the throttle (as in keeping it at 60mph) I notice little hesitations. They are subtle enough that at first I thought it was either bumps in the road are suspension issues. Then I thought I might be running out of gas. Then I thought I remember reading something hear about that being a sign of running lean.
Other things to note. The engine temp. doesn't appear to change noticeable... If you give it more gas it smooths out....
The only recent change has been the add of the MSD 6AL and a tune-up by my mechanic.
Any ideas?? :cheers:
Tim M.
I have an interesting new problem. After I have been driving for a while if I am really light on the throttle (as in keeping it at 60mph) I notice little hesitations. They are subtle enough that at first I thought it was either bumps in the road are suspension issues. Then I thought I might be running out of gas. Then I thought I remember reading something hear about that being a sign of running lean.
Other things to note. The engine temp. doesn't appear to change noticeable... If you give it more gas it smooths out....
The only recent change has been the add of the MSD 6AL and a tune-up by my mechanic.
Any ideas?? :cheers:
Tim M.
Safety Car
Joined: Feb 1999
Posts: 3,632
Likes: 14
From: Fountain Hills AZ
Re: Am I running lean??? (still-learning)
Mine was behaving the same as yours and under the same conditions. Turned out to be too much ignition advance. Under light load and some rpms, the vacuum advance was giving me more than the engine wanted. If you are running vacuum advance, try disconnecting and plugging it and then take a test drive. Also, I've read that Vortec headed engines don't like as much advance as other engines. Holley dp's are usually jetted on the rich side out of the box so I wouldn't expect it to be the problem.
Safety Car
Joined: Jun 2001
Posts: 4,004
Likes: 2
From: Severna Park Md
Re: Am I running lean??? (still-learning)
Ignition crossfire under the cap? Change the plugs and see if it makes a difference. Plugs that look good can still be bad. Built up resistance in any one plug can cause the charge to jump terminals inside the cap and fire another cylinder out of time. Also check ignition wires for good insulation. With MSD and a hotter spark there is more likelyhood of ignition wires grounding out on frame or block. Seperate the wires and run them clear of frame and or block. You can check for grounding plug wires by looking under the hood with the engine running at night when its dark. Turn off all light sources and look for arcing of the wires against any possible ground. Sometimes these misfires will only pronounce themselves under "no load" conditions as you have described.
[Modified by Jvette73, 2:41 AM 4/20/2002]
[Modified by Jvette73, 2:44 AM 4/20/2002]
[Modified by Jvette73, 2:41 AM 4/20/2002]
[Modified by Jvette73, 2:44 AM 4/20/2002]
Thread Starter
Racer
Joined: Nov 2000
Posts: 473
Likes: 0
From: Centreville, VA USA
Re: Am I running lean??? (still-learning)
Sweet. This gives me a couple of things to look for. It sounds like the first thing I should do is pull a couple of plugs and visually inspect them. That will at least give me a heads up if I am lean. After that, it is typical troubleshooting.
Tim M.
Tim M.
