At wits end....need help
#1
TECH Regular
Thread Starter
iTrader: (17)
Join Date: Oct 2005
Location: Tinley Park, IL.
Posts: 465
Likes: 0
Received 0 Likes
on
0 Posts
At wits end....need help
What I've got
97 lt1 stock bottom end
LE 2.2 heads / cam
58 mm tb
My problem
PCM is adding, on average, 10-15% more fuel(short term) on bank 2 and the long term fuel trim is maxed @+ 25% . Bank 1 is pulling fuel at idle as it always does and it's long term is -10 to-17%.
B1 injector pulse width is 3.3 ms at idle( p/w even out under throttle but fuel trims only improve by 60-70%)
B2 is at 5.8 ms at idle
This all started last fall when I threw a code for bank 2 high voltage. Figured no big deal swapped out both o2 sensors as preventative. Still there
What I've done
Cyl leak down. All within 5% of each other
Injector balance test. Perfect
Checked for good spark on all 8. All good
Readjusted all the rockers to be safe
Swapped out o2 extensions to see if there is a short. Good
Swapped plugs. Still there
I was getting an occasional high voltage spike on my bank 2 rear o2 sim. Disconnected both of them cause they're disabled anyways. Still there
Sprayed carb cleaner and traced vac lines with propane. Still there
fuel pressure is 38@ idle w/ vacuum and 45 without( old holly fpr)255lph walbro-7yrs old/20k mi on it
all injectors ohm out within .1 of each other.( 30lb svo)
My thoughts without throwing unnecessary parts at it
Possible maf
Possible PCM
Short in the engine harness
Pull the intake to visually check the intake gaskets for vac leaks
Here is a pic of the plugs from 2-8
Why 2 and 4 look decent and 6 n 8 look like **** is beyond me. Bank 1 look like I just installed them
my first thought when looking at the plugs, with the thought that all 4 cyl are getting the same amount of fuel, is 2 and 4 have a vac leak of some sort. To me, The added fuel explains 6 and 8 being rich.
Any other ideas?
97 lt1 stock bottom end
LE 2.2 heads / cam
58 mm tb
My problem
PCM is adding, on average, 10-15% more fuel(short term) on bank 2 and the long term fuel trim is maxed @+ 25% . Bank 1 is pulling fuel at idle as it always does and it's long term is -10 to-17%.
B1 injector pulse width is 3.3 ms at idle( p/w even out under throttle but fuel trims only improve by 60-70%)
B2 is at 5.8 ms at idle
This all started last fall when I threw a code for bank 2 high voltage. Figured no big deal swapped out both o2 sensors as preventative. Still there
What I've done
Cyl leak down. All within 5% of each other
Injector balance test. Perfect
Checked for good spark on all 8. All good
Readjusted all the rockers to be safe
Swapped out o2 extensions to see if there is a short. Good
Swapped plugs. Still there
I was getting an occasional high voltage spike on my bank 2 rear o2 sim. Disconnected both of them cause they're disabled anyways. Still there
Sprayed carb cleaner and traced vac lines with propane. Still there
fuel pressure is 38@ idle w/ vacuum and 45 without( old holly fpr)255lph walbro-7yrs old/20k mi on it
all injectors ohm out within .1 of each other.( 30lb svo)
My thoughts without throwing unnecessary parts at it
Possible maf
Possible PCM
Short in the engine harness
Pull the intake to visually check the intake gaskets for vac leaks
Here is a pic of the plugs from 2-8
Why 2 and 4 look decent and 6 n 8 look like **** is beyond me. Bank 1 look like I just installed them
my first thought when looking at the plugs, with the thought that all 4 cyl are getting the same amount of fuel, is 2 and 4 have a vac leak of some sort. To me, The added fuel explains 6 and 8 being rich.
Any other ideas?
Last edited by Formula WS6; 01-18-2012 at 11:12 PM.
#2
TECH Fanatic
iTrader: (5)
Join Date: Sep 2008
Location: Salem/Keizer
Posts: 1,120
Likes: 0
Received 0 Likes
on
0 Posts
Ok...just a wild guess here.....PCM grounds get checked/cleaned just to be sure? Sometimes a visible once-over is not good enough. I'd trace them down, and unbolt/clean all ground points leading to the PCM.
Just a though. Sorry to hear about your problems.
-James-
Just a though. Sorry to hear about your problems.
-James-
#6
TECH Regular
Thread Starter
iTrader: (17)
Join Date: Oct 2005
Location: Tinley Park, IL.
Posts: 465
Likes: 0
Received 0 Likes
on
0 Posts
thanks for replying
the whole opti (delco) has maybe 500 miles on it. Not to say it's not possible but the injectors ohm'd and balanced out evenly on all 8. I've posted it up in lt1/4 section as well for addtitional ideas if you care to read .
https://ls1tech.com/forums/lt1-lt4-m...need-help.html
the whole opti (delco) has maybe 500 miles on it. Not to say it's not possible but the injectors ohm'd and balanced out evenly on all 8. I've posted it up in lt1/4 section as well for addtitional ideas if you care to read .
https://ls1tech.com/forums/lt1-lt4-m...need-help.html
#7
Banned
iTrader: (10)
thanks for replying
the whole opti (delco) has maybe 500 miles on it. Not to say it's not possible but the injectors ohm'd and balanced out evenly on all 8. I've posted it up in lt1/4 section as well for addtitional ideas if you care to read .
https://ls1tech.com/forums/lt1-lt4-m...need-help.html
the whole opti (delco) has maybe 500 miles on it. Not to say it's not possible but the injectors ohm'd and balanced out evenly on all 8. I've posted it up in lt1/4 section as well for addtitional ideas if you care to read .
https://ls1tech.com/forums/lt1-lt4-m...need-help.html
Trending Topics
#8
TECH Regular
Thread Starter
iTrader: (17)
Join Date: Oct 2005
Location: Tinley Park, IL.
Posts: 465
Likes: 0
Received 0 Likes
on
0 Posts
tested power with a noid light and pulse with a fuel injector pulse timer. it pulses the injector for 3 seconds at a rate of 10ms. I pressurize the fuel system, record the psi, pulse the injector, and record the drop in fuel pressure. did it for all 8 and they're identical.
#9
Banned
iTrader: (10)
tested power with a noid light and pulse with a fuel injector pulse timer. it pulses the injector for 3 seconds at a rate of 10ms. I pressurize the fuel system, record the psi, pulse the injector, and record the drop in fuel pressure. did it for all 8 and they're identical.
Have you put the noid light in while the engine is running? Put the noid light in and started it? Does it blinky blinky?
#10
TECH Regular
Thread Starter
iTrader: (17)
Join Date: Oct 2005
Location: Tinley Park, IL.
Posts: 465
Likes: 0
Received 0 Likes
on
0 Posts
Yes it goes blinks,blinky.. Lol
I think improper flow in my idle circuit is my cause. I eliminated my nitrous outlet plate and bolted the throttle body directly to the intake and my p/w on the injector dropped to 4.2 ms,short terms started to stabilize @+\-3 % on bank 2. Bank 1 was still slightly lower but I'm sure the fuel fouled spark plugs and possibly fouled o2 sensor aren't helping me.
Thanks for all the help and suggestions
I think improper flow in my idle circuit is my cause. I eliminated my nitrous outlet plate and bolted the throttle body directly to the intake and my p/w on the injector dropped to 4.2 ms,short terms started to stabilize @+\-3 % on bank 2. Bank 1 was still slightly lower but I'm sure the fuel fouled spark plugs and possibly fouled o2 sensor aren't helping me.
Thanks for all the help and suggestions
#12
TECH Regular
Thread Starter
iTrader: (17)
Join Date: Oct 2005
Location: Tinley Park, IL.
Posts: 465
Likes: 0
Received 0 Likes
on
0 Posts
I was at 150 and I stepped up to 200 on a Nitrous outlet plate. I had a nitrous works plate on a 150 shot and to me it had a similar hit as the 200 N/O plate. When the car was dyno'd to verify A/F on spray I was running autolite 104's and it was fine. But I caved to the masses and I was told by many that I was going to have a melt down with the combo. I'm running the br7ef's If I remember correctly.