Classic/Antique Car Repair/1970 GMC engine


My truck would only run about 15 minutes, then die.  I would try to restart it but no fire, I'd have to wait an hour or more. I replaced the fuel pump, checked for vacuum in the gas tank, currently don't have a fuel filter.  I replaced the ignition coil today and it ran for 30 minutes now, but still dies. It turns over but no fire for an hour or so.  It's a 350 with HEI distributor.

Several things come to mind/ I would tie a fuel pump pressure gage into the fuel  line and see what happens to the fuel pressure and flow when the engine dies. Second make sure that there isd the dielectric silicon grease under the ignition module.  The grease is neessary to make a good path for heat to transfer from the module to the distributor body.

Classic/Antique Car Repair

All Answers

Answers by Expert:

Ask Experts


Brad Sears


All automotive including antique and collectible. However if the car has been modified I can only answer in general terms and maybe get you pointed in the right direction.


Automotive tech instructor. Syndicated auto columnist 1970's though the early 1990's. Syndicated auto radio talk show, Ask Brad About cars, CBS Radio 70's through 90's TV Show "Last Chance Garage" 1980's PBS-TV syndicated. Auto instructor for the following companies: Fram Autolyte Holly Carter AMF Ford Motor University Of Conn Blue Hills Technical School Sugar River Technical Center Grew up in a family garage in Needham Mass and turned wrenches from the age of 14.

Manchester Union Leader, Nashua Telegraph, Motor Service Magazine, Yankee Magazine, Popular Mechanics (Saturday Mechanic early 80's), Los Angeles Times, New York Times, and lots more.

More than I care to remember. Basically Franklin Technical Institute in Boston, Northeastern University, Fitchburg State Teachers College, Tufts University, and a lot of factory schools along the way.

Awards and Honors
Moto Award winner. And much more.

©2016 All rights reserved.