Jump to content


Diagnosis help


Recommended Posts

My new (to me) 73 240z behaves badly at idle and low speeds. It feels like a plug or two is fouled and missing. However, when I put my foot in it, things get better as if the fouled plugs clear themselves. Checks on the ignition system appear to show that things are normal, and there's no signs of obvious fouling on the plugs. So, I begin to wonder if it's carburation.

Details: 1973 240Z, Automatic. Dual point distributor, Dual 32/36 Weber DGVs, EGR intact but air pump belt is off.

It's been a number of years since I did serious engine work and I seem to have forgotten my diagnosis skills. Point me in the right direction?


-Jim Kirkpatrick

Walnut Creek, CA

Link to comment
Share on other sites

Some things to consider. With your foot in it....full throttle, you will be at full advance in your distributor. I had a similar problem and discovered that the centrifical advance assembly was worn out and ran like crap at lower RPMs. Also, at full throttle the only circuits in your carbs that are working are the high speed circuits, so possibly the balance and or idle adjust screws may need adjustment, to achieve low speed and idle smoothness.

Link to comment
Share on other sites

I bought a rebuilt distributor and replaced it. Things have smoothed out considerably. I suspect that all I need do now is to re-balance the carbs. All my efforts at balancing before were offset by the bad cent. advance.

Thanks for the suggestion.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.