5ltrlady
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- Vt S1 5ltr auto
Hey all. I'm suffering a misfire gremlin and im at my wit's end. Please chuck some suggestions at me.
Car is a 1999 VT commodore S1 with the 5ltr conversion. Auto. Engine is stock.
Consistent misfire through entire rev range. From idle to 4000. Doesn't change in any gears, forward or reverse and doesn't change with heat. Replacing the dizzy didn't make any difference, it was timed properly with a timing light, all leads connected in correct order and place and new dizzy was installed exactly the same as the removal of the old one.
So far I've changed
Spark plugs
Leads
Coil
Dizzy (complete)
Ignition module
Done the wire reroute to avoid noise from coil to ICM.
Dropped the cats and it made no difference.
Fuel pump
Fuel reg
Fuel injectors serviced and no leaks.
Fuel filter
Compression tested. Results are in psi
Passenger side
136
137
140
135
Drivers side
140
155
136
137
Checked all earth's, cleaned and reassembled.
Ignition ring replaced as car was having trouble starting. Misfire started before this. This solved the starting issue.
Pcv checked and new hose fitted due to age deterioration (passenger side)
Maf swapped with known working
IAC and TPS swapped with known working.
No air leaks at all.
Rockers checked for twists or imbalance due to 155psi compression reading on cyl 5. This was not the issue. Thinking valve? But don't want to pull the head if I'm missing something.
All fuses checked and replaced if old/burned to ensure clean connection, all relays replaced with known working. Have pulled pcm fuse to reset. Made no difference. Battery has been disconnected. Made no difference.
Oxy sensors replaced with known working.
Codes: 22,23,32,35,48. Only code that sticks around after reset is 48. I'm aware I have a HES that acts as crankshaft sensor.
Car is a 1999 VT commodore S1 with the 5ltr conversion. Auto. Engine is stock.
Consistent misfire through entire rev range. From idle to 4000. Doesn't change in any gears, forward or reverse and doesn't change with heat. Replacing the dizzy didn't make any difference, it was timed properly with a timing light, all leads connected in correct order and place and new dizzy was installed exactly the same as the removal of the old one.
So far I've changed
Spark plugs
Leads
Coil
Dizzy (complete)
Ignition module
Done the wire reroute to avoid noise from coil to ICM.
Dropped the cats and it made no difference.
Fuel pump
Fuel reg
Fuel injectors serviced and no leaks.
Fuel filter
Compression tested. Results are in psi
Passenger side
136
137
140
135
Drivers side
140
155
136
137
Checked all earth's, cleaned and reassembled.
Ignition ring replaced as car was having trouble starting. Misfire started before this. This solved the starting issue.
Pcv checked and new hose fitted due to age deterioration (passenger side)
Maf swapped with known working
IAC and TPS swapped with known working.
No air leaks at all.
Rockers checked for twists or imbalance due to 155psi compression reading on cyl 5. This was not the issue. Thinking valve? But don't want to pull the head if I'm missing something.
All fuses checked and replaced if old/burned to ensure clean connection, all relays replaced with known working. Have pulled pcm fuse to reset. Made no difference. Battery has been disconnected. Made no difference.
Oxy sensors replaced with known working.
Codes: 22,23,32,35,48. Only code that sticks around after reset is 48. I'm aware I have a HES that acts as crankshaft sensor.
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