Chevy Silverado/ GMC Sierra Forum Discuss the Chevrolet Silverado and GMC Sierra here.

88 TBI 5.7 fresh rebuild running gremlins

Thread Tools
 
Search this Thread
 
  #11  
Old 08-20-2011 | 11:24 PM
sraey8's Avatar
Thread Starter
|
Beginner
Joined: Jul 2011
Posts: 31
Default

What's the function? I mean, as it goes through its motions, what's happening? Is the tip suppose to move in and out? If so, is this activated by temp, or instantly by 12v? Does this piece require ground to work? I ask because, laying across the t-body and switching on key, nothing happens and I can't manually move the pointed tip. Educate me
 
  #12  
Old 08-21-2011 | 09:52 AM
Mr_Shamrock's Avatar
Chevrolet/GMC, Racing, Recreational Forum Moderator
Joined: Apr 2009
Posts: 2,267
Default

Yes the tip moves in and out to vary the amount of air that goes in the motor for it to idle properly. Pull it out and make sure the tip is clean as well as the hole it goes in. To test it you will need a multimeter to check resistance across the terminals. I don't have the specs in front of me, but can probably look them up in my manual if you don't have one. You don't want to plug it in and have it extend out when it is not in the throttle body. If you do and then try to screw it back in it will damage the tip trying to force it in there.
 
  #13  
Old 08-21-2011 | 12:11 PM
sraey8's Avatar
Thread Starter
|
Beginner
Joined: Jul 2011
Posts: 31
Default

Should I be able to push the tip in /out or screw it in / out ? It seems to be frozen and I wonder if this means its locked up or that it must be powered to actuate ?
How do I test it ? - I don't have a manual
 

Last edited by sraey8; 08-21-2011 at 12:15 PM.
  #14  
Old 08-21-2011 | 02:13 PM
sraey8's Avatar
Thread Starter
|
Beginner
Joined: Jul 2011
Posts: 31
Default

Got to wondering why there was no burning marks on # 7 plug; so pulled plug and checked compression - NONE !?!?! What the H?!??? Bout time to set the s.o.b. on fire.

Valves are adjusted - rocker arms going through motions.

Any explanations ?
 

Last edited by sraey8; 08-21-2011 at 02:16 PM.
  #15  
Old 08-21-2011 | 03:08 PM
sraey8's Avatar
Thread Starter
|
Beginner
Joined: Jul 2011
Posts: 31
Default

U think if u do something enough times, u may have a idea on how to do it right. With no compresion showing on #7, I'm about ready to pull manifold / head and see a busted ring after pulling piston; but first just for kicks, I backed off the valves and boom, I've got air blowing and sucking through the plug hole. So after all the valve adjusting, I still managed to not get it right. Apparently, if the valves are over adjusted, u get no compression; who'd a thunk it.

Re-adjusting and will report
 
  #16  
Old 08-21-2011 | 04:06 PM
MrDragon's Avatar
Senior Member
Joined: Jul 2011
Posts: 304
From: Indianapolis
Default

Just a tip on the valve adjustment. A quarter turn past snug will set any 350, 305,or 327 to get it running. Then you can get minor detail adjustment from there. Yes you can easily overtighten, you didn't build a sprint car motor.
 
  #17  
Old 08-21-2011 | 10:18 PM
sraey8's Avatar
Thread Starter
|
Beginner
Joined: Jul 2011
Posts: 31
Default

Got timing set to 8-10 initial degrees ( @ idle) , and valves are adjusted so that motor will idle on its own although idle is a little ruff. Aside from the ruff idle, I'm getting some backfiring through the mullers when I mat the gas and am hopiing this is due to too much air or what the computer is reading as a vaccum leak since I've yet to put valve covers back on along with air filter and vaccum hoses from covers to throttle body.

Does this sound right to u guys, that not having the whole top end buttoned up will cause a ruff idle and some muffler backfiring ?
 
  #18  
Old 08-21-2011 | 10:33 PM
MrDragon's Avatar
Senior Member
Joined: Jul 2011
Posts: 304
From: Indianapolis
Default

It should be ok, plus I'm betting you'll probably ser your timing a little closer to 4° once you button it all up and warm it up.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
sraey8
Chevy Silverado/ GMC Sierra Forum
6
04-05-2015 03:11 PM
dearborn2415
Chevy Silverado/ GMC Sierra Forum
1
10-25-2011 04:45 PM
crewcab75
Automotive Parts for sale
0
10-08-2008 11:49 AM
Thraxxx
Chevy Silverado/ GMC Sierra Forum
4
10-22-2007 05:31 PM
MotoWarrior
Chevy Silverado/ GMC Sierra Forum
3
12-27-2006 01:10 AM




All times are GMT -5. The time now is 07:37 AM.