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VS V6 intermittent miss/stumble
- Thread starter Immortality
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It keeps stumbling until you give it some gas
ephect
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Hrmm, pointing towards a sticky/faulty iac which would cause issues on idle.. Possible low voltage or coil pack causing **** spark.
Is this a hot engine only fault or can it do it cold?
Is this a hot engine only fault or can it do it cold?
michealh877
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Mine does it after 20 minutes of driving no matter what temp . Any ideas ?
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Quick update,
Problem has occurred once or twice since posting but not in a long time now.
I'm off the opinion that I have a sick lifter. I was in the process of fitting some high ratio rockers a while ago but had to re-fit the standard rockers and it didn't run well for a bit which I can only put down to a sick lifter. I have since fitted the high ratio rockers without issue.
At this stage engine runs fine.
Sometimes has a slightly rough idle but nothing to really worry about as the engine runs fine otherwise, so we soldier on until something else fails........
Problem has occurred once or twice since posting but not in a long time now.
I'm off the opinion that I have a sick lifter. I was in the process of fitting some high ratio rockers a while ago but had to re-fit the standard rockers and it didn't run well for a bit which I can only put down to a sick lifter. I have since fitted the high ratio rockers without issue.
At this stage engine runs fine.
Sometimes has a slightly rough idle but nothing to really worry about as the engine runs fine otherwise, so we soldier on until something else fails........
yxyx64
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do you happen to have a log when it stumbled, send both your xdl and adx.
assume you have done iac/tb clean (and maf) but methinks next time I would gently tap tps when it stumbles (or gently move shaft now and see if it does anything) - maybe one crook spot in tps resistor.
other thoughts - both hot and cold kinda rules out ecu transition glitch (or sensors coming online with time/temp) VSS unlikely. CAS no, MAF no....ECT no .... as idle glitch is too specific (but you mentioned under load - have YOU felt it do this under load? did it feel the same - this would rule out tps resistor but maybe still wiring.....tiny start of regulator diaphragm leak at high vacuum - no as would be bad by now.
lifter hmm.....idle pressure low helping collapse maybe......game enough to pull plug leads to see what cylinder effect next time it stumbles. Not a big fan of pulling valve covers from running motors but it may tell you something about pushrod feed and head you towards a lifter body. Or maybe just get u messy and confirm that oil stinks.....that is all I usually get out of it.
thinking more...do a idle log anyhow and watch for any tps voltage spikes when you slightly touch shaft, bpw spikes or even battery voltage odd movements around idle - give alt a tap anyhow to shock brushes. I am thinking short overfuel for stumble but maybe a momentary ignition change would do same. Anything funny in spark advance..........but still thinking about a dirty spot in tps.
assume you have done iac/tb clean (and maf) but methinks next time I would gently tap tps when it stumbles (or gently move shaft now and see if it does anything) - maybe one crook spot in tps resistor.
other thoughts - both hot and cold kinda rules out ecu transition glitch (or sensors coming online with time/temp) VSS unlikely. CAS no, MAF no....ECT no .... as idle glitch is too specific (but you mentioned under load - have YOU felt it do this under load? did it feel the same - this would rule out tps resistor but maybe still wiring.....tiny start of regulator diaphragm leak at high vacuum - no as would be bad by now.
lifter hmm.....idle pressure low helping collapse maybe......game enough to pull plug leads to see what cylinder effect next time it stumbles. Not a big fan of pulling valve covers from running motors but it may tell you something about pushrod feed and head you towards a lifter body. Or maybe just get u messy and confirm that oil stinks.....that is all I usually get out of it.
thinking more...do a idle log anyhow and watch for any tps voltage spikes when you slightly touch shaft, bpw spikes or even battery voltage odd movements around idle - give alt a tap anyhow to shock brushes. I am thinking short overfuel for stumble but maybe a momentary ignition change would do same. Anything funny in spark advance..........but still thinking about a dirty spot in tps.
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I did try to log but I wouldn't never do it when I had the laptop connected. It hasn't done it in months.
It first started doing it when I fitted a high flow oil filter which would show an increase in oil pressure. When the issue occurred with the lifters it was run with the rocker covers off, didn't show anything as everything was moving as it should, got messy when I brought the revs up to see what would happen when the oil pressure increased.
It has had a different TPS on it but no different that I can remember.
I have since altered the tune to many times to count, if it did influence the issue then it probably won't happen again.
It first started doing it when I fitted a high flow oil filter which would show an increase in oil pressure. When the issue occurred with the lifters it was run with the rocker covers off, didn't show anything as everything was moving as it should, got messy when I brought the revs up to see what would happen when the oil pressure increased.
It has had a different TPS on it but no different that I can remember.
I have since altered the tune to many times to count, if it did influence the issue then it probably won't happen again.
Demmo
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Has there been any updates on this problem over the years?
As my vs has developed a on an off miss under load yet it seems ok when load comes off so anyone had similar probs and have solved it by???? Any suggestions. I know the car is old and I am to but I prefer the vs over the wife's late model stato
As my vs has developed a on an off miss under load yet it seems ok when load comes off so anyone had similar probs and have solved it by???? Any suggestions. I know the car is old and I am to but I prefer the vs over the wife's late model stato
commodore665
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after six years , I'm betting that immortality fixed it , wait and see if he replies to this post
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Sorry, missed this.
It's been so long I can't say for sure but I did eventually find that the car did not like the Eagle ignition leads I was using. I ended up changing to OEM type Bosch LPG leads which got rid of a ignition stumble which was more apparent with all the engine mods I'd done as well as the lean cruise function (cruising on the motorway above 80km/h with light to moderate throttle application). Another issue we encountered but not sure if it was related to the original issue was the main starter wiring loom came loose and would occasionally rub on the PS pump pulley when going over bumps etc. It eventually got to the point when it had worn through all the insulation that the engine would cut out momentarily when hitting a bump.
Another issue that I have encountered on a couple of high mileage ecotecs are worn push rods but I'm not sure on the exact cause. When I fitted the high ratio rockers I may have taken out some of that wear in the rockers push rod seats.
Because of all the various mods I had done over the years of ownership I had spent considerable time playing with the tune looking for various ways to adjust for different mods to maintain stock car behaviour like the enlarged TB and high ratio rockers. I know that at one stage I went the wrong way with an adjustment which causes some weird issues but that wasn't until after this problem had disappeared I believe.
We also ran into a problem with a replacement coil, the coil which was only just replaced failed and took out the output on the dfi module so the car only ran on 4 cylinders. Eventually I fitted a complete set of genuine Delphi coils and DFI module (along with the Bosch LPG leads and new plugs). Take a close look at the ignition coils around the spark plug terminals, I found all the original coils had cracks in the insulation by the output posts.
The VS V6 Commodore also has a known issue with the O2 sensors wiring causing one bank to run lean. Cleaning all the earth points on the engine and chassis is a good start and replacement of the O2 sensors doesn't hurt either. I ended up re-wiring the O2 sensor heater earths to eliminate the problem but the poor mans option is to cut the heater circuit of the offending O2 sensor to stop it sending a false signal to the PCM and upsetting the tune. After that I also replaced the injectors as I'm sure one was sick as one banks fuel trims was a fair bit off from the other which did not change with the new O2 sensors fitted.
I really don't know if all these rambling are of any help to you. If maybe you can be a bit more specific on your exact issue maybe we can suggest a course of action but for anything like this my first suggests start like this.
1. Clean the throttle body
2. clean the MAF
3. New fuel/intake filter
4. replace the plugs and leads if they are getting on in age/mileage.
5. Run some injector cleaner
I do concur though, I liked the VS too. So much so I ended up getting a HSV VSII Senator some time after the missus VS was replaced with a VX Calais.
It's been so long I can't say for sure but I did eventually find that the car did not like the Eagle ignition leads I was using. I ended up changing to OEM type Bosch LPG leads which got rid of a ignition stumble which was more apparent with all the engine mods I'd done as well as the lean cruise function (cruising on the motorway above 80km/h with light to moderate throttle application). Another issue we encountered but not sure if it was related to the original issue was the main starter wiring loom came loose and would occasionally rub on the PS pump pulley when going over bumps etc. It eventually got to the point when it had worn through all the insulation that the engine would cut out momentarily when hitting a bump.
Another issue that I have encountered on a couple of high mileage ecotecs are worn push rods but I'm not sure on the exact cause. When I fitted the high ratio rockers I may have taken out some of that wear in the rockers push rod seats.
Because of all the various mods I had done over the years of ownership I had spent considerable time playing with the tune looking for various ways to adjust for different mods to maintain stock car behaviour like the enlarged TB and high ratio rockers. I know that at one stage I went the wrong way with an adjustment which causes some weird issues but that wasn't until after this problem had disappeared I believe.
We also ran into a problem with a replacement coil, the coil which was only just replaced failed and took out the output on the dfi module so the car only ran on 4 cylinders. Eventually I fitted a complete set of genuine Delphi coils and DFI module (along with the Bosch LPG leads and new plugs). Take a close look at the ignition coils around the spark plug terminals, I found all the original coils had cracks in the insulation by the output posts.
The VS V6 Commodore also has a known issue with the O2 sensors wiring causing one bank to run lean. Cleaning all the earth points on the engine and chassis is a good start and replacement of the O2 sensors doesn't hurt either. I ended up re-wiring the O2 sensor heater earths to eliminate the problem but the poor mans option is to cut the heater circuit of the offending O2 sensor to stop it sending a false signal to the PCM and upsetting the tune. After that I also replaced the injectors as I'm sure one was sick as one banks fuel trims was a fair bit off from the other which did not change with the new O2 sensors fitted.
I really don't know if all these rambling are of any help to you. If maybe you can be a bit more specific on your exact issue maybe we can suggest a course of action but for anything like this my first suggests start like this.
1. Clean the throttle body
2. clean the MAF
3. New fuel/intake filter
4. replace the plugs and leads if they are getting on in age/mileage.
5. Run some injector cleaner
I do concur though, I liked the VS too. So much so I ended up getting a HSV VSII Senator some time after the missus VS was replaced with a VX Calais.