Author Topic: engine cuts out intermittently under load  (Read 439 times)

Offline travisr1988

  • Registered Users
  • *
  • Posts: 126
engine cuts out intermittently under load
« on: December 21, 2012, 12:00:21 AM »
I have a 79 c20,350, qjet, rv cam. Ran great for awhile, still runs great sometimes. My issue is lately when I get on it a little pulling out of a driveway it'll cut out and it'll do it real bad sometimes. It seems to happen more when its hot, it pops sometimes when it happens, carb was rebuilt 6 months ago, timing chain, and distributor were replaced 4 months ago. Timing is fine, disconnected vacuum advance and plugged line, problem didn't seem to be there anymore until I drove 5 miles and parked it for an hour then drove a couple miles again. Gas mileage doesn't seem to be harmed as it still gets 12.5mpg city. What should I be checking for?
1979 Chevrolet Silverado C20 rclb cammed 355/th400/4.10 - sold
1977 Chevrolet Custom Deluxe c10 rcsb ss 355/th350/3.73

Online Captkaos

  • OWNER and Administrator
  • Administrator
  • Senior Member
  • *****
  • Posts: 16239
    • http://www.73-87chevytrucks.com
Re: engine cuts out intermittently under load
« Reply #1 on: December 23, 2012, 12:40:33 PM »
Verify no vacuum leaks and timing and report back.

Offline Elpresidente

  • Registered Users
  • *
  • Posts: 206
Re: engine cuts out intermittently under load
« Reply #2 on: December 23, 2012, 03:37:33 PM »
Sounds like a lean condition, had the same problem with my truck. You can feel a bit of a lean surge coming on as you accelerate, then it pops and keeps on running eh?
If so then swap the rods/jets 1 stage richer, if that solves the problem then fine tune it from there.
'82 Chev Scottsdale
Proud to be Canadian \m/

Offline ralphhemi

  • Newbie
  • Posts: 99
  • Newbie
Re: engine cuts out intermittently under load
« Reply #3 on: December 23, 2012, 04:11:01 PM »
Sounds like a lazy accelerator pump , shut the truck off remove the air cleaner and look down the 2 front barrels and move the throttle by hand to see how big of a shot of gas  its gets try adjusting the linkage to get a bigger shot.
Ralphhemi

Offline travisr1988

  • Registered Users
  • *
  • Posts: 126
Re: engine cuts out intermittently under load
« Reply #4 on: December 28, 2012, 03:26:37 PM »
Timing is good,didn't find vacuum leaks. Did find cheap plug wires touching exhuast. Gotta wait until payday to get new wires, until then it's undriveable as problem has worsened considerably. I'll check back in after replacing plugs and wires. 
1979 Chevrolet Silverado C20 rclb cammed 355/th400/4.10 - sold
1977 Chevrolet Custom Deluxe c10 rcsb ss 355/th350/3.73

 


Facebook Comments