I'm at a loss. Sputtering under acceleration, rough idle.
08-13-2013, 12:17 PM
#1
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Car: 1989 IROC & ROLL-Z
Engine: L98 Vortec FIRST TPI
Transmission: T56, Mech Speedo
Axle/Gears: G92 J65 3.27
I'm at a loss. Sputtering under acceleration, rough idle.
Last week I upgraded my bone stock L98 to a vortec machine.
906 Vortec heads
- Beehive springs & retainers
- Screw in studs
SDPC vortec base
SLP runners
08-502-08 Compcams cam
New timing chain
1.52 roller rockers
New pushrods
ACdelco R42LTS Plugs
New Bosch plug wires
I cannot for the life of me figure out where this sputtering is coming from under acceleration and the rough idle.
Ignition:
Gapped plugs to .035"
Checked every plug wire with DMM, all around 500 ohms per foot
cap and rotor look great
Checked coil and P/U coil for shorts/grounds, all checked out
Other:
Checked for vacuum leaks
set TPS to .54v
checked injector ohms (all between 16.8 - 17.2)
PLEASE HELP
906 Vortec heads
- Beehive springs & retainers
- Screw in studs
SDPC vortec base
SLP runners
08-502-08 Compcams cam
New timing chain
1.52 roller rockers
New pushrods
ACdelco R42LTS Plugs
New Bosch plug wires
I cannot for the life of me figure out where this sputtering is coming from under acceleration and the rough idle.
Ignition:
Gapped plugs to .035"
Checked every plug wire with DMM, all around 500 ohms per foot
cap and rotor look great
Checked coil and P/U coil for shorts/grounds, all checked out
Other:
Checked for vacuum leaks
set TPS to .54v
checked injector ohms (all between 16.8 - 17.2)
PLEASE HELP
08-13-2013, 02:17 PM
#2
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Car: 1989 IROC & ROLL-Z
Engine: L98 Vortec FIRST TPI
Transmission: T56, Mech Speedo
Axle/Gears: G92 J65 3.27
Re: I'm at a loss. Sputtering under acceleration, rough idle.
Went out and grabbed a bit of data. I'm no expert but I couldn't see anything obviously wrong here.
Anyone care to take a look? (rename to .xdl to open)
Anyone care to take a look? (rename to .xdl to open)
08-14-2013, 12:22 PM
#3
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Car: 1989 IROC & ROLL-Z
Engine: L98 Vortec FIRST TPI
Transmission: T56, Mech Speedo
Axle/Gears: G92 J65 3.27
Re: I'm at a loss. Sputtering under acceleration, rough idle.
Had a quick thought. The hooker 2055 set i ordered didn't line up with the Y pipe very well so I had an exhaust leak right below the O2 sensor. Was reviewing the datalog and noticed the O2 sensor and AFR values were all over the place.
Fixed the exhaust leak this morning and the problem is 97% fixed. idles much better and the sputtering has all but gone away. There is still sputtering in low RPM's under load. Say 40mph in 5th gear gives about 1500 RPM's and will sputter.
Anyone?
Fixed the exhaust leak this morning and the problem is 97% fixed. idles much better and the sputtering has all but gone away. There is still sputtering in low RPM's under load. Say 40mph in 5th gear gives about 1500 RPM's and will sputter.
Anyone?
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