Misfiring Continues after $900 bill....Powertrain error.

[Vzniko]

Hi everyone,

Had posted a thread a few months ago about the misfiring issues I was experiencing on a VZ (dual fuel) commodore. Powertrain error
would come up also every now and then,

with codes
PO300- Multicylinder misfire
PO303- Cylinder 3 misfire


After a spending tons of money on dodgy mechanics, wrongly diagnosing it, I bought a repair manual and tried to do some things myself
and see where it takes me.

Anyway, I have replaced all the coil packs (one mechanic replaced 1 so I decided to do the rest myself). Fitted new NGK platinum plugs, and I did a compression test just the other day and all came up clear (compression on all cylinders was 13.5atm) and builds up very quick, which eliminated any problem with internals like valves etc.

I am starting to think that it could be electronic related, PCM or ECU, however the repair manual said if ECU faulty would cause glitches on the computer, and so far have not experience any of that.

I am getting pretty tired of this game, and I am sick of repairing this car, I have spend so much money and energy and I am still back to where I have started.

Any thoughts of what I should do next - I really do not want to take it to Holden, They will have a look - Clear the codes - charge me a few hundred bucks and go by the process of elimination like everyone else, costing me hundreds along the way.....

REGARDS

P.S car has done 160,000 and problem evident on both LPG and petrol so I have no reason to think its LPG related only.

 

[304runner]

Yeah gone are the days of heading into the garden shed and pulling bits of the old lawn mower to fix an issue with the commodore.

My first thought was the ECU but I have very limited experience with the tech savvy Holden's so head to a Holden workshop and have it fixed once and for all.. Its not as if they will push out a newish car if they haven't fixed it.

 

[Boonz]

We have had countless problems with genuine gas setups on the alloytecs at work... majority of them is caused by the patch harness thats used to tee into the injector harness.
you need to determine wether its a gas ir petrol problem.
Start off by unplugging the gas system patch harness and go from there

Sent from my MB860 using Tapatalk 2

 

[richardpalinkas]

Where I work, there was a commodore that also had an injector fault code. Replaced everything like the injector and coils but still missfired. It did turn out to be a faulty ecu. Have you replaced the injector?

 

[Vzniko]

Where I work, there was a commodore that also had an injector fault code. Replaced everything like the injector and coils but still missfired. It did turn out to be a faulty ecu. Have you replaced the injector?

Yeah I think only one injector had been replaced (Injector 2 I think). I am thinking of doing an injector cleaning in case they are clogged (holden does that for around $190) they said,
is that worth doing at all?

I just want to eliminate all possibilities before I head off to the ECU as they quoted me around $1000 for parts and labour....

Car has been running okay now for around a week - no fault codes but the rough idling is still there.

It does it on both LPG and PETROL because when I switch it over it still misfires rough idling etc - LPG is worse though.....

 

[greenacc]

When they refund your $900 the ECU won't hurt so much

 

[holdensupporter2005]

I have a 2006 VE SV6 which I had SVI LPG system installed on. During the winter just about every morning it would run rough when the car was started on a cold morning, then when it switched over to the LPG after a few minutes it would display Engine warning light. Have a Garmin GPS with an ECOHD unit which displays error codes on engine. Had several codes of Misfiring Cylinders P0300, P0304, etc... After a few minutes and high revs the engine would do a lot of shuddering and misfiring then all of a sudden it would start running smooth and would run fine for the rest of the day. I have had almost all injectors replaced by the LPG installer and several $100 later still have the problem. It did this almost every day during last winter. Summer it was fine. Just started doing it again this past few weeks since the weather has got cold again. I'm starting to think it is to do with temp sensor or something else. Very annoying and frustrating. I was starting to blame the LPG system, but after several google searches appears to be a common problem with the VZ / VE commodores.

 

[Sharpie]

My Vz 3.6 is at a Holden dealer at the moment for the same kind of issue. It would run on 5 cylinders intermittently cold or hot on both fuels even at 100kph for about 5 seconds. Ive replaced all coils and plugs and cleaned all injectors. They have had it for a week and have had no trouble codes logged in the ecu. Got a call today saying it could be the either the lpg emulator or patch harness, it has a Parnell system fitted. They tried another ecu and that still didnt fix it, hopefully ill get her back next week but a costly exercise.....

 

[boxdog]

My Vz 3.6 is at a Holden dealer at the moment for the same kind of issue.

Me too. I have 2004 VZ 3.6 running on SprintGas duel fuel and does the same thing. Auto elec reckons it's one of the cylinders misfiring because of the ECU. Has anyone had it fixed by replacing the ECU? Just curious before I plunk down $780... Thanks

 

[ryanosim]

Hi guys, was it the ECU in the end that fixed the problem?