powertrain warning light on LPG

2006 HOLDEN COMMODORE
130,000 MILES • 3.6L • V6 • RWD • AUTOMATIC
Avatar
BOA69
  • MEMBER
  • 34 POSTS
I have a 2006 HOLDEN VZ V6EXECUTIVE 3.6L ALLOYTECH which has an aftermarket SPRINT LPG system installed (it also runs on Unleaded Petrol)Dual Fuel). ONLY when running on LPG and under load at about 2000rpm the "CHECK POWERTRAIN" warning light comes on dash and the engine runs like its dropped a few cylinders until I switch engine off, then when started the light disappears and it runs fine until under load again. ""THIS ONLY HAPPENS WHEN RUNNING ON LPG""
I had a GSCAN fault tool hooked up to it and it showed the following error codes and messages:

P0300 - Random/Multiple Cylinder Misfire Detected.
P0304 - Cylinder 4 Misfire Detected.
P0443 - Evaporative Emmission Control System Purge Solenoid Circuit.
P1632 - Immobiliser Transponder Response Distorted.

Can you give me any information as to which parts I should replace first to fix these faults?

Will it hurt the engine if I keep driving with these faults in the system?

Which Spark Plugs should I use (will NGK-R BPR7EFS-15 be ok) and the recommended Spark Plug Gap (1.1mm)?

I have recently done all repairs listed below:
Replaced the Air Filter
Cleaned MASS Sensor
Cleaned Throttle Body
Cleaned Intake Manifold & Plenum
Replaced Engine Oil + Filter
Replaced Heater Control Valve
Added Injector Cleaner to Unleaded Fuel
NONE OF THESE HAVE FIXED THE FAULTS

Today I plan to replace the Spark Plugs & Plenum/Intake Manifold Gasket and inspect the 6x Individual Coil Packs a bit closer.
ANY HELP - INFO OR ENGINE DIAGRAMS WOULD BE GREATLY APPRECIATED.

THIS ONLY HAPPENS WHEN ENGINE IS RUNNING ON "LPG" & HAS NEVER HAPPENED WHEN RUNNING ON UNLEADED PETROL
Dec 25, 2015 at 11:32 AM
Avatar
MHPAUTOS
  • ✓Experienced Mechanic
  • 31,937 POSTS
Replace the coils and plugs, LPG has a higher flash point than petrol that is it takes more energy to ignite so a misfire will show up on lpg before petrol, this is a fairly common problem.
Dec 26, 2015 at 6:35 AM
Avatar
BOA69
  • MEMBER
  • 34 POSTS
thanks for your reply MHPAUTOS, Is it ok to replace just 1 coil pack or should I replace all 6 together? its just that I cant afford to buy all 6 of them in the 1 go, repco wants $235.00 for the 6 of them, does this sound right?
Dec 26, 2015 at 10:07 AM
Avatar
MHPAUTOS
  • ✓Experienced Mechanic
  • 31,937 POSTS
You can do them one at a time, no problem, that price is about right for retail, just do the one that's a problem now, but be prepared to replace others down the track.
Dec 26, 2015 at 12:16 PM
Avatar
BOA69
  • MEMBER
  • 34 POSTS
cheers for your replies MHAUTOS, I have finally fixed the faults, I replaced the spark plugs to a plug with only a 1.1mm gap - replaced cylinder no.4 coil - replaced Plenum Gasket - disconnected the battery to reset the computer. I have now done over 300kms on LPG and the faults have not re-appeared. I think the plugs in it were wrong because they had a gap of about 2.5mm which seems way to big I think.
Dec 29, 2015 at 2:58 PM
Avatar
MHPAUTOS
  • ✓Experienced Mechanic
  • 31,937 POSTS
Plug gaps are very critical, the 1.1is the correct gap,
Dec 30, 2015 at 9:00 PM
Add a reply
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.

Ask a new question

Frequently Asked Problems for This Vehicle

Advertisement