[Shadow240z]

Ok I have a '72 240 with SU's and header, The car starts up ok if it has been sitting for a while. (LIke overnight). If I don't let the engine get too warm than I can drive it fine for about 15-20 min. Then the tach starts to jump around, and there is a noise like the ingition is shorting or a plug doesnt fire, but it's sparatic. If the rpms don't stay pretty high(3000 and up) than the car will die when this "blip" occurs. If it does than it is extermely hard to get it started. The last time it happened I couldn't start it and now it is stranded at a friends house. Please help.
Jeff
'72 240z
Washington

 

[zmefly]

are you still running points? it sounds like what my Z was doing before my distributor died. of course what coincided with that was that which was the cause was the drive shaft of the distributor the one that your oil pump turns broke!. i would check for wobble and play in the distributor, then go from there i hope this gives you a place to start.

 

[luggnut73]

Shadow, Fly is right, it sounds to me like ignition, either from a coil or condencer shorting out when warmed . Try this , just a shot in the dark, spray the inside of the dist. cap with W D 40 this will displace any moisture if there is a crack that is shorting things out and wont hert anything. If this solves the prob . your done , if not replace the condencer, its the little silver cylinder that is attached to the points in the dist. , they are cheep . The tach is wired into the ignition and if it is malfunctioning look there . I have a dist from my '73 that you can have if you pay for the shipping , if you dont live to far from Portland Ore. I' ll drive it to you for nothing . Lets keep these classics on the road ! Get back to me if you want any more info. My friend has a '72 parts car that runs if that helps. And the tach is good.Gary

 

[johnh240]

If you can you might want to get it started in the dark and see if you can see where it is arcing at. If the plug wires are corroded or you have real high resistance in the cap sometime you can get arcing right at the coil wire to the closest available ground.

 

[Terry G]

Check to make sure you are getting a nice fat spark off the coil. After it's warmed up, turn it of, then have someone start it (or use a remote) while you hold the line of the coil about 1/2" from the block. It's gotta be nice and bright.

Don't know much about the distributor, that could be the problem as well.

 

[mizhele]

hello i'd check the fuel delivery last time this happen to my 71 240z i could drive for 10 -20 minutes then it would die..it was the fuel pump...if your starving the float bowls while driving once they run too low of fuel level the car will begin to be speratic untill it finally dies out...my car did ok at idle and would deliver enough fuel to fill the floats to to run 10 -20 minutes then id have to shut it down turn the ignition to start long enough to refill the floats bowls then it would be ok for another 10-20 minutes or so...just a thought you might check out...good luck michele