LT1-LT4 Modifications 1993-97 Gen II Small Block V8

gm847 86 kpa @ idle?

Thread Tools
 
Search this Thread
 
Old 06-15-2010, 11:14 AM
  #1  
Teching In
Thread Starter
 
dan catalyst's Avatar
 
Join Date: Mar 2009
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
Default gm847 86 kpa @ idle?

what kpa is your 847 pulling at idle? mine is only pulling 86, that seems really low,so im thinking i might have a intake lifter adjusted to tight.tps % is 0 at idle. what do you guys think,this cam has to pull more than 86 at idle right?
Old 06-15-2010, 03:49 PM
  #2  
TECH Enthusiast
 
stevo9389's Avatar
 
Join Date: Mar 2009
Location: Clearwater
Posts: 681
Likes: 0
Received 7 Likes on 6 Posts

Default

i will have to dig up some datalogs and see where i was at.
Old 06-15-2010, 04:17 PM
  #3  
8 Second Club
iTrader: (4)
 
Tony Shepherd's Avatar
 
Join Date: Oct 2002
Location: Round Rock TX
Posts: 2,913
Likes: 0
Received 2 Likes on 2 Posts

Default

You should be in the 40-55 kpa range with that cam. You either have a vaccum leak or valve adjustment problem.
Old 06-15-2010, 04:46 PM
  #4  
Teching In
iTrader: (1)
 
zz17iroc's Avatar
 
Join Date: Jul 2008
Posts: 33
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by Tony Shepherd
You should be in the 40-55 kpa range with that cam. You either have a vaccum leak or valve adjustment problem.
I agree with Tony. My car idles at 53-55 kpa all day.
Old 06-15-2010, 04:57 PM
  #5  
TECH Enthusiast
 
stevo9389's Avatar
 
Join Date: Mar 2009
Location: Clearwater
Posts: 681
Likes: 0
Received 7 Likes on 6 Posts

Default

didn't find it but my cc306 motor was around 47-50.
Old 06-15-2010, 07:34 PM
  #6  
Teching In
Thread Starter
 
dan catalyst's Avatar
 
Join Date: Mar 2009
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
Default

ok here is the deal, i just installed the engine, it was stock w/ bolt ons and tuned.ive added the mods in my sig,and just started it up trying to get it to idle.it runs great untill it starts to heat up,then rpm falls off and it starts to run like crap. upon closer inspection w/ the vacuum gauge and a log, it does pull a dead steady 70-75 kpa when its running well, then as it heats up and the rpms drop to below 800,it starts to bounce from 80-90 kpa and run like poo.i adjusted the spark correction vs map vs coolant temp table to not pull timing as the engine heated up.it was pulling timing in the 70-80 kpa and 190* area because the stock engine would be under slight load in those cells.so, all the timing data needed to be adjusted for the higher kpa(lower vacuum) this cam pulls.the stock cam pulls 40ish kpa,so i just moved all the data surounding those cells to the 70 kpa area.damn, i miss my hei,lol.

Last edited by dan catalyst; 06-15-2010 at 08:56 PM.
Old 06-15-2010, 09:03 PM
  #7  
Teching In
Thread Starter
 
dan catalyst's Avatar
 
Join Date: Mar 2009
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
Default

one other thing i just noticed, in the main spark table,around 70 kpa the timing is 29*,and around 40 kpa its like 34 ish,so i bet after i add some timing to the cells the car is idleing in now, the vacuum will pick up some more.
Old 06-16-2010, 12:48 AM
  #8  
10 Second Club
iTrader: (26)
 
Wicked94Z's Avatar
 
Join Date: Jul 2005
Location: Spokane, Wa
Posts: 3,725
Likes: 0
Received 1 Like on 1 Post

Default

you need to be looking at the closed tps spark table....
Old 06-16-2010, 12:52 AM
  #9  
TECH Senior Member
iTrader: (8)
 
gregrob's Avatar
 
Join Date: Sep 2008
Location: 6,000+ feet
Posts: 5,130
Likes: 0
Received 4 Likes on 4 Posts

Default

^Werd

"Closed TPS Spark Advance vs RPM"

That is where you set idle spark. I would start around 29-30deg and bump it up from there seeing what it likes, not going over about 34.

JMO
Old 06-16-2010, 01:11 PM
  #10  
TECH Fanatic
iTrader: (2)
 
blackz93's Avatar
 
Join Date: May 2003
Location: nc
Posts: 1,661
Likes: 0
Received 1 Like on 1 Post
Default

I think mine was bewteen 55 and 60 kpa when idling.
Old 06-16-2010, 01:38 PM
  #11  
9 Second Club
iTrader: (7)
 
quik95lt1's Avatar
 
Join Date: Dec 2008
Location: Rhode Island
Posts: 4,464
Likes: 0
Received 12 Likes on 10 Posts

Default

yea 87 is definatly not right i had an old cam similar to the cc306 and it idled at like 55 ish........you've got some sort of vacuum leak it sounds like..........my new motor idles at like 75 and ive got a massive cam that dwarfs the 847.
Old 06-16-2010, 06:01 PM
  #12  
Teching In
Thread Starter
 
dan catalyst's Avatar
 
Join Date: Mar 2009
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
Default

ok,thaks alot guys. ive adjusted the closed tps idle advance.it didnt do much, idles a little better.0-0,400-27 800-28,1200-30 its now pulling 70 kpa, but the idle drops and the engine dies when the water temp rises above 140 ish.what does your guys' spark correction table look like? here is mine.



Deg. C ----------------------------Kpa
kpa>30 -35- 40 - 45 - 50 - 55 - 60 - 65 - 70 - 75 - 80 - 85 - 90 - 95 - 100
-16 5.0 5.0 5.0 6.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0
-4 5.0 5.0 5.0 6.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0 8.0
8 4.0 4.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0 5.0
20 0.0 -7.0 -7.0 -7.0 -7.0 -7.0 -7.0 -2.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
32 0.0 -7.0 -7.0 -7.0 -7.0 -7.0 -7.0 -2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
44 0.0 -7.0 -7.0 -7.0 -7.0 -7.0 -7.0 -2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
56 0.0 -7.0 -7.0 -7.0 -7.0 -7.0 -7.0 -5.0 -3.0 0.0 0.0 0.0 0.0 0.0 0.0
68 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
80 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
92 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
104 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -3.0
116 0.0 0.0 0.0 0.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -3.0 -6.0
128 0.0 0.0 0.0 0.0 -3.0 -3.0 -6.0 -6.0 -6.0 -6.0 -6.0 -6.0 -6.0 -6.0 -6.0

Last edited by dan catalyst; 06-16-2010 at 09:55 PM.
Old 06-16-2010, 06:03 PM
  #13  
Teching In
Thread Starter
 
dan catalyst's Avatar
 
Join Date: Mar 2009
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
Default

here is my main spark table too
----- 25 - 30 - 35 - 40 - 45 - 50 - 55 - 60 - 65 - 70 - 75 - 80 - 85 - 90 - 95 - 100
400 16.0 16.0 27.0 28.0 28.0 26.0 24.0 24.0 27.0 28.0 26.0 24.0 24.0 11.0 9.0 8.0
600 26.0 26.0 29.5 32.0 32.0 31.0 31.0 25.0 27.0 29.0 26.0 26.0 25.0 18.0 9.0 8.0
800 29.0 32.0 34.0 35.0 35.0 34.0 32.0 26.0 28.0 27.0 28.0 28.0 26.0 20.0 13.0 9.0
1000 32.0 38.0 39.0 36.0 34.0 33.0 31.0 29.0 29.0 29.5 32.0 32.0 31.0 27.0 13.0 9.0
1200 34.0 40.0 39.0 38.0 37.0 35.0 34.0 33.0 32.0 34.0 35.0 35.0 34.0 28.0 16.0 12.0
1400 35.0 40.0 41.0 40.0 38.0 36.0 35.0 34.0 35.0 39.0 36.0 34.0 33.0 27.0 18.0 14.0
1600 35.0 38.0 38.0 38.0 37.0 35.0 34.0 32.0 37.0 39.0 38.0 37.0 35.0 30.0 20.0 16.0
1800 35.0 37.0 40.0 40.0 38.0 36.0 35.0 34.0 39.0 41.0 40.0 38.0 36.0 31.0 23.0 19.0
2000 35.0 37.0 40.0 40.0 38.0 37.0 36.0 35.0 40.0 37.0 33.0 30.0 27.0 26.0 23.0 23.0
2200 35.0 37.0 40.0 40.0 39.0 37.0 37.0 36.0 41.0 39.0 36.0 33.0 30.0 30.0 27.0 27.0
2400 35.0 37.0 40.0 40.0 40.0 38.0 37.0 36.0 42.0 39.0 37.0 36.0 34.0 33.0 30.0 30.0
2800 35.0 37.0 40.0 40.0 39.0 38.0 37.0 36.0 41.0 39.0 38.0 37.0 37.0 37.0 34.0 33.0
3200 35.0 37.0 40.0 40.0 39.0 38.0 38.0 37.0 41.0 39.0 38.0 38.0 37.0 37.0 35.0 34.0
3600 35.0 37.0 40.0 41.0 40.0 39.0 38.0 38.0 42.0 40.0 42.0 42.0 41.0 38.0 36.0 36.0
4000 35.0 38.0 40.0 41.0 40.0 39.0 38.0 38.0 42.0 41.0 43.0 43.0 41.0 38.0 36.0 36.0

Last edited by dan catalyst; 06-16-2010 at 09:52 PM.
Old 06-17-2010, 01:06 AM
  #14  
10 Second Club
iTrader: (26)
 
Wicked94Z's Avatar
 
Join Date: Jul 2005
Location: Spokane, Wa
Posts: 3,725
Likes: 0
Received 1 Like on 1 Post

Default

could be an o2 problem that would show up when the car hits closed loop. force it into open loop and see if it'll stay running
Old 06-17-2010, 07:53 AM
  #15  
TECH Veteran
iTrader: (23)
 
FASTFATBOY's Avatar
 
Join Date: Nov 2002
Location: Mobile Ala
Posts: 4,860
Likes: 0
Received 2 Likes on 2 Posts

Default

Look at closed loop BLMs, do you have an exhaust leak?
Old 06-17-2010, 09:00 AM
  #16  
10 Second Club
iTrader: (26)
 
Wicked94Z's Avatar
 
Join Date: Jul 2005
Location: Spokane, Wa
Posts: 3,725
Likes: 0
Received 1 Like on 1 Post

Default

Originally Posted by dan catalyst
here is my main spark table too
----- 25 - 30 - 35 - 40 - 45 - 50 - 55 - 60 - 65 - 70 - 75 - 80 - 85 - 90 - 95 - 100
400 16.0 16.0 27.0 28.0 28.0 26.0 24.0 24.0 27.0 28.0 26.0 24.0 24.0 11.0 9.0 8.0
600 26.0 26.0 29.5 32.0 32.0 31.0 31.0 25.0 27.0 29.0 26.0 26.0 25.0 18.0 9.0 8.0
800 29.0 32.0 34.0 35.0 35.0 34.0 32.0 26.0 28.0 27.0 28.0 28.0 26.0 20.0 13.0 9.0
1000 32.0 38.0 39.0 36.0 34.0 33.0 31.0 29.0 29.0 29.5 32.0 32.0 31.0 27.0 13.0 9.0
1200 34.0 40.0 39.0 38.0 37.0 35.0 34.0 33.0 32.0 34.0 35.0 35.0 34.0 28.0 16.0 12.0
1400 35.0 40.0 41.0 40.0 38.0 36.0 35.0 34.0 35.0 39.0 36.0 34.0 33.0 27.0 18.0 14.0
1600 35.0 38.0 38.0 38.0 37.0 35.0 34.0 32.0 37.0 39.0 38.0 37.0 35.0 30.0 20.0 16.0
1800 35.0 37.0 40.0 40.0 38.0 36.0 35.0 34.0 39.0 41.0 40.0 38.0 36.0 31.0 23.0 19.0
2000 35.0 37.0 40.0 40.0 38.0 37.0 36.0 35.0 40.0 37.0 33.0 30.0 27.0 26.0 23.0 23.0
2200 35.0 37.0 40.0 40.0 39.0 37.0 37.0 36.0 41.0 39.0 36.0 33.0 30.0 30.0 27.0 27.0
2400 35.0 37.0 40.0 40.0 40.0 38.0 37.0 36.0 42.0 39.0 37.0 36.0 34.0 33.0 30.0 30.0
2800 35.0 37.0 40.0 40.0 39.0 38.0 37.0 36.0 41.0 39.0 38.0 37.0 37.0 37.0 34.0 33.0
3200 35.0 37.0 40.0 40.0 39.0 38.0 38.0 37.0 41.0 39.0 38.0 38.0 37.0 37.0 35.0 34.0
3600 35.0 37.0 40.0 41.0 40.0 39.0 38.0 38.0 42.0 40.0 42.0 42.0 41.0 38.0 36.0 36.0
4000 35.0 38.0 40.0 41.0 40.0 39.0 38.0 38.0 42.0 41.0 43.0 43.0 41.0 38.0 36.0 36.0
needs a lot of work
Old 06-17-2010, 09:39 AM
  #17  
TECH Senior Member
iTrader: (8)
 
gregrob's Avatar
 
Join Date: Sep 2008
Location: 6,000+ feet
Posts: 5,130
Likes: 0
Received 4 Likes on 4 Posts

Default

It's quite odd
Old 06-17-2010, 12:13 PM
  #18  
Teching In
Thread Starter
 
dan catalyst's Avatar
 
Join Date: Mar 2009
Posts: 29
Likes: 0
Received 0 Likes on 0 Posts
Default

yeah, these spark tables arnt working out so well when i try to drive the car....lol.ive gone back to the bolt on mail order timing tables.also im keeping the car in open loop for now. im thinking i have a tight valve or valves.im going to do another valve lash and see if my vacuum comes up any. will report back tomorrow.



Quick Reply: gm847 86 kpa @ idle?



All times are GMT -5. The time now is 12:13 AM.