« previous next »
Pages: [1]   Go Down

Author Topic: truck won't idle in gear  (Read 3904 times)

Offline 48t

  • New Users
  • Posts: 2
truck won't idle in gear
« on: March 17, 2007, 12:09:00 pm »
ok here's what i'm working on.  it's a 1987 V25 4X4 rclb sb350 tbi and a  th400 with vacuum madulation.  ok it has a edelbrock top end kit (heads, intake, cam, and lifters.)  for some reason he wanted us to remove the roller hydro lifters and put in flat tappet hydro lifters.  as well as a smaller cam.  we are not sure why he wanted this but hey what ever.  ok here is the problem in park it idles great and strong but when put in gear the eng looks like its gonna jump out of the eng bay and the hole truck tries to take off but right after its put into gear it bogs and a few seconds later it dies.  this thing has electronic timing.  we pulled the little electronic advance wire and set timming to zero like the book says and then shut down and reconect the wire and fire it back up.  it has a edelbrock chip and that fixed nothing.  so what should i check?  i have 20"s of vacuum at idle in park when put in gear it drops to like 15 or so and dies.this thing has been in my friends shop in and out for a long long time now and i want to get it fixed and gone.

Logged

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19180
Re: truck won't idle in gear
« Reply #1 on: March 18, 2007, 11:48:00 am »
It sounds more than anything like an electrical connection problem. Check the grounds at the back of the cylinder head, at the frame, and engine block. If the engine is jumping that much you better check your mounts too.  

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

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

Offline 48t

  • New Users
  • Posts: 2
Re: truck won't idle in gear
« Reply #2 on: March 18, 2007, 12:01:00 pm »
how important is the egr system on this truck?  they left the tubes to the headers diconnected but all else connected.  i disconnected the vacuum line from the pump to the tbi.  and gained some vacuum.  how much vacuum should this thing pull at idle?  i have 19-20"s but in gear it drop to like 10-15"s and the eng wobles and jerks and dies.  in park it idle nice and smooth.

Logged

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19180
Re: truck won't idle in gear
« Reply #3 on: March 22, 2007, 05:22:00 am »
You disconnected what line from the TBI to what pump? Confused. Check for vacuum leaks at the base of the throttle body. Mist a small amount of carb clean at it while it's idling and see if it changes the engine speed.  

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

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

Offline 1tondump

  • Newbie
  • Posts: 3
Re: truck won't idle in gear
« Reply #4 on: May 04, 2007, 11:13:11 am »
I'm having the same problem. Some one suggested abondoning the carburated system all together because of this nagging problem. Has anyone tried that?
Logged

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19180
Re: truck won't idle in gear
« Reply #5 on: May 04, 2007, 03:23:25 pm »
 ???

Do you mean TBI system?
Logged
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

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

Offline 1tondump

  • Newbie
  • Posts: 3
Re: truck won't idle in gear
« Reply #6 on: May 06, 2007, 03:45:43 pm »
Yes.
Logged

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19180
Re: truck won't idle in gear
« Reply #7 on: May 06, 2007, 09:13:23 pm »
That would be very foolish
Logged
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10
Pages: [1]   Go Up
« previous next »