Fine tuning 77 GMC truck


  #1  
Old 10-12-05, 02:44 AM
N
Member
Thread Starter
Join Date: Oct 2005
Posts: 31
Upvotes: 0
Received 0 Upvotes on 0 Posts
Question Fine tuning 77 GMC truck

Have swb stepside 77 GMC Sierra truck 250-6cyl, 1BBL, auto trans which I drive daily. Put a new float in gas tank 3 y.ago. My gas register doesn't function correctly. Is this fixable even with such old gauge technology?

Additionally, had carb rebuilt by reputable rebuilder. I can't seem to get the max performance out of carb it once had. Engine diesels(run-on) after turning off ignition. Set fast and curb idle RPM according to Haynes manual but still seem to lack top end pep. At one time I could hang with the best on interstate; now I'm hesitant to get on. Ignition timing(set to GM spec). New plugs and wires,coil, dist. cap,etc; vac advance works fine. Have all 3 necessary basics-fuel, air, and spark. The engine has a new head, excellent compression, bottom end bored over 60 with hot cam.The truck is running but there is room for improvement. What have I done wrong or overlooked?
All advice and info are very much appreciated. Thank you for your time and help.
Steve
 
  #2  
Old 10-12-05, 02:50 AM
C
Member
Join Date: Apr 2005
Posts: 238
Upvotes: 0
Received 0 Upvotes on 0 Posts
buy a new sending unit for the tank, if ther problem started when the carb was changed? then its the carb, if it can't be tunned the replace it,, buy a new carb.
 
  #3  
Old 10-12-05, 03:14 AM
N
Member
Thread Starter
Join Date: Oct 2005
Posts: 31
Upvotes: 0
Received 0 Upvotes on 0 Posts
Smile

The problem started before I rebuilt the carb. Are there methods to check wiring from harness to tank,etc. Would you advise changing fuel gauge also?
 
  #4  
Old 10-12-05, 03:22 AM
C
Member
Join Date: Apr 2005
Posts: 238
Upvotes: 0
Received 0 Upvotes on 0 Posts
the sending unit wire can be taken off,,does the gauge go to zero with the wire off? it should, then ground the wire to the tank and the gauge should go to full.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: