Jump to content



Timing 101a


  • Please log in to reply
5 replies to this topic

#1 Shelby

Shelby

    Rookie

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 50,164 posts
  • Gender:Male
  • Location:Ocala, Florida
  • Model:Other

Posted 23 March 2003 - 08:14 PM

there seems to be some  arguement about  checking the base timeing with or with out the vacum advance  hook'd up
the normal operation of the vacum advance system is to not have enought vacum at  hot idle to advance the  timeing, thats why the manual  says  nothing about  unhooking it, BUT  all things are not always as they should be , so to asure the  vacum advance is not holding the timeing any , it  takes no time at all to  unhook the hose and see if it is, and sence you already have the timeing light on  it  why not set the base timeing   while you  know  for a fact the  timeing is at base
then it's a simple matter to  recheck it after putting the hose back on
while  we're at  seting the base timeing it's a good time to check a few other things  such as the mechanical advance system, easy  just  rev the engine  while watching the  timeing mark , with  a  moderate rev of  2000 to 2500 the timmeing mark should  move advance'd about  10  aditional degrees from base , and  with a rev to 4k or so it should  be aprox 33-35 btdc, this is with out the vacum advance hook'd up, if  every thing is in the ball park, connect the  vac hose back up and  lightly rev the engine the advance now  should be much  greater then it was with out the  vacum hose on , the  vac  adv port  will rearly  see full  manifold vacum  but 10to 12  inches of  vacum should advance the timeing  10 to 12 degrees, this is adj by the  way.
now in less then 5 minutes you have done a  bunch of things, not just  set the base timeing and call'd it  done, you've check 'd out the dist advance system, the vacum advance system and the  base timeing plus check'd the throddle  for being close'd in the idle possition
if you  have a enought vacum at idle to move the timeing  you'l need to redo the  ISC, TPS, and MPS adj , and check the cable  for proper slack ,and the  hoses  for any  leaks, includeing the inj houseing  

now there is much more to the dist and it's advance systems  but this is just a guick check  you should do when seting the timeing , not just  say it's at 10 btdc and call it a day , and it only takes a couple more minutes
Shelby trance's StarQuest i-x.net
86MightyMax89Tsi, MPi , 20g ;) (sold:( )
88TSI Silver
89TSI red auto





#2 jabattle

jabattle

    Member

  • Members
  • PipPip
  • 108 posts
  • Location:killeen, texas
  • Interests:spool 'em if ya got 'em

Posted 13 November 2003 - 02:20 PM

Good call Shelby.
  Thanks, I need to set the timing again after this thread. I set it 10 BTDC and called it the day.

                                                                         jb
'87 quest TSI, stock, but evolving like a muthaf##ka
'98 montero sport,
'00 galant es6, sport package
'02 kaw zx-6r, jetted, flow cdr, timing advance
two '05 VW jettas GLI
'89 accord, raptors exh

#3 JustPaus_88TSi

JustPaus_88TSi

    This is my forest, and I am not afraid.

  • Members
  • PipPipPipPipPip
  • 13,960 posts
  • Gender:Male
  • Location:Gilbert, Arizona
  • Model:Conquest

Posted 24 February 2004 - 03:34 AM

Luckily my car was already set to 10 BTDC...i'll have to check it again with the vac. adv. unhooked...... Why am I only seeing this now :smile.gif
Posted Image
88TSi-S16G~19x8.5's/19x10.5's~Anti-M-Power~S&M~FIP TBpro2R~E46 projector HID's/Fogs
2001 IS300-GTE swap~T04E 60-1 Garrett hifi~18" Volk CE28N~Tein Comfort Sport coilovers~TurboEast~PFS~Apex-I~Greddy~Blitz
2005 LS430-Staggered 20" Maya/Trafficstar DTS'~14k/12k Extreme Drop BC Coilovers~KYOEI-USA Representin...Bippu Status.

#4 Technology

Technology

    TheNerdyProfessor

  • Members
  • PipPipPipPipPip
  • 11,391 posts
  • Gender:Male
  • Location:Minnesota
  • Interests:Lots of boost!
  • Model:Other

Posted 18 February 2005 - 04:17 PM

what would cause a high vacuum at idle?  because my timing gets pretty dang advanced when i re-hook up the vacuum line. we set my base at 10BTDC with the line NOT hooked up.

does the vac. advance not affect the engine when under boost?

#5 ChadC

ChadC

    Member

  • Members
  • PipPip
  • 361 posts
  • Location:D/FW, Texas
  • Interests:Gold & Boosted

Posted 27 February 2005 - 01:14 PM

QUOTE
does the vac. advance not affect the engine when under boost?



under boost it retards the timing

#6 Shelby

Shelby

    Rookie

  • Moderators
  • PipPipPipPipPipPipPipPip
  • 50,164 posts
  • Gender:Male
  • Location:Ocala, Florida
  • Model:Other

Posted 16 June 2008 - 11:10 AM

QUOTE (Technology @ Feb 18 2005, 05:17 PM) <{POST_SNAPBACK}>
what would cause a high vacuum at idle?  because my timing gets pretty dang advanced when i re-hook up the vacuum line. we set my base at 10BTDC with the line NOT hooked up.

does the vac. advance not affect the engine when under boost?



several reasons for this,, the most common is useing the wrong  vacuum port
th1st of the 3 ina row ports on theTBI system is a port'd vacuum , meaning it does not see any vac signal ntill thethroddle plate is open'd some,, then it drops off after a certain distance of travel example 1/2 way to wot

for  non oem ntake systems you donot want to use a full vacuum  signal port,, unless you have a throddle body  with a port'd vac  signal port,, you need to forget about useing  the vacuum advance funtion of the dist all togather,,but  retain the  retard under boost funtion by useing a boost only signal port ahead of the throddle plate
Shelby trance's StarQuest i-x.net
86MightyMax89Tsi, MPi , 20g ;) (sold:( )
88TSI Silver
89TSI red auto




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users