Author Topic: '85 dually runs awful at startup  (Read 4369 times)

Offline tierraverde

  • Newbie
  • Posts: 3
'85 dually runs awful at startup
« on: July 23, 2002, 09:39:00 PM »
I have an '85 454 7.4 liter dually that runs awful when first started up--it blows black exhaust and sounds like a boat (chug chug chug). My husband just replaced the EGR valve and it warms up a bit faster, but still the black smoke. Once it warms up it runs great. We're thinking it needs a new carburetor. Any ideas? Thanks!


Offline 79SilveradoK30

  • Newbie
  • Posts: 53
Re: '85 dually runs awful at startup
« Reply #1 on: July 24, 2002, 11:12:00 AM »
Well, I'd check to see if it's backfiring first, because it kinda sounds like that's happening. That's usually caused by old spark plugs, or bad wires in the plug lines or distributor. Although I'm not an expert, I'd check that first, just to be sure.


Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18980
Re: '85 dually runs awful at startup
« Reply #2 on: July 24, 2002, 08:42:00 PM »
Sounds like too much fuel, check the carb and check for vac leaks. If all looks ok, time to overhaul the carb.

,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline tierraverde

  • Newbie
  • Posts: 3
Re: '85 dually runs awful at startup
« Reply #3 on: July 26, 2002, 12:56:00 PM »
It backfires only occasionally, and then it only does it once.


Offline tierraverde

  • Newbie
  • Posts: 3
Re: '85 dually runs awful at startup
« Reply #4 on: July 26, 2002, 12:58:00 PM »
It does seem to run rich (I can smell gas). We had our mechanic fix a clogged jet awhile back and he said he couldn't get the carb to run right. The problem started about a month after.


Offline RSBAD454

  • Junior Member
  • ***
  • Posts: 533
Re: '85 dually runs awful at startup
« Reply #5 on: September 18, 2002, 11:07:00 AM »
too bad you dont live in cali, i have rebuilt many Q jets. you need to have the carb replaced or rebuilt. im sure it has a lot of miles on it. probably a combo of oil and fuel for the black smoke.

“If you're listening to a rock star in order to get your information on who to vote for, you're a bigger moron than they are.”
http://prosites-prs.homestead.com/
http://

Offline 79350pu

  • Newbie
  • Posts: 8
Motown
« Reply #6 on: September 27, 2002, 03:48:00 PM »
Where's Cali, CA.?