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3 fouled plugs, only on one engine side?

slimecity

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Hi - I have an issue with carbonised spark plugs - just inherited an ecotec V6 which hadnt been looked after - I've changed the oil and the previous oil looked like it had been in there for ages.....It has 220K on the clock. Have just changed the spark plaugs after noting that the 3 on the passenger side bank were fouling - the new plugs are also still fouling - quite noticeably. However very little blue smoke (except under heavy acceleration) and the oil level is not noticeably dropping (I'm running high quality 20-40). The carbon on the 3 plugs is light and dusty and is affecting all 3 cylinders on the passenger side. The plugs on the drivers side are spotless. The leads must be low-impedance types, they are all reading at consistent values. Having this problem surely indicates that the coil-pack is OK. I was thinking is this likely to be the valve stem oilseals? I understand there is one of these for each each valve? Why would all 3 go at once only on this side if thats the case? I will have a go at replacing these myself once I buy a Gregorys manual. Could this problem actually be something else? Any advice from you's guys appreciated....!
 

Decicrate

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Could be a case of the 02 sensor on the passenger side is dead or dying and giving a incorrect reading, which will increase or decrease the fuel to that bank depending on how it is reading.

The VS also had a issue with 02 sensor grounding, if you do a search on here you will find a mod to make to the 02 wiring to help fix the issue.
 

slimecity

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Thanks heaps for the replies guys - altho that woud suck if thats the problem as I have fitted new pacemakers and brand new O2 sensors......I will look up the relevant thread to do some mods and some sensor testing, cheers
 

slimecity

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I think I know what the problem is - recently got a new memcal chip off an auction site here - the code must be mucking up the 02 sensor readings to the CPU, or something like that. Will do a diagnostic 2nite to see if any codes come up, and replace the memcal to go back to the standard coded me,cal to see if that sorts the prob....cheers for pointing out thats a fuel, rather than an oil issue.....!
 

Not_An_Abba_Fan

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Fitting new extractors will contaminate the sensors and make them read incorrectly. Do a code check and it will at tell you where to start. I'd say your sensor is stuffed.

The issue with the O2 sensor earth is only on the RHS. The heater circuit interfered with the sensor circuit and made it read incorrectly also. The Holden fix was to cut the heater wire and tape it up, but people have had success earthing the sensor back to the ECU.
 

slimecity

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Hi there Mr (not an) Abba fan - I think you mite be a genius! (Sorry also I didnt end up buying pacemakers from you, just managed to sort out a deal here in NZ). I'm only getting a code 12 from the computer however your point sounds pretty valid. I'll replace both the sensors as a precaution and see if the problem continues, cheers!
 

Brett_jjj

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If you only earth the 02 sensor to the body, the ECU will see a large voltage variation that will completely stuff up the 02 sensor readings. The 02 sensors must be earthed to the engine block as per the factory setup.. The VS 02 sensor modification mentioned above just adds an extra earth to the current earth wire(s). First thing is make sure the factory 02 sensor earths are spotlessly clean and tight where they connect up to the front of the engine block.
I found that with some VSV6's, when I was experimenting with the tune, that if the original factory memcal version was originally BSTK, and you try to fit a newer updated memcal version or a tune that uses a newer VS tune as a base, that the 02 sensor readings will be all over the place and it wont go into closed loop properly. Ive not yet found a fix for this problem, adding extra earths does not make any difference to it, and the weird thing is the 02 sensors will work perfectly again once the BSTK memcal is refitted.
Ive had to use the BSTK version to do my tuning on and it works and runs perfectly. Ive even tried fitting different VS ECU's (later updated ones ) to see if that made a difference, and it doesnt. No one has really been able to explain why this happens with the BSTK version either.. Ive actually ran into a few people now who have the the BSTK memcal factory fitted and theyve had similar problems when fitting a tuned memcal thats based on a different version etc etc....
 

Decicrate

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^^^ The wiring mod worked perfectly for me.
Always had issues with the two banks being a lot different. Changed O2 sensors, no different, did wiring mod both sensors started to read within a couple percent of each other. I also have the engine earthed to the body with 2 extra earth straps.
 

Brett_jjj

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Yeah, the factory earths seem to be problem with these cars. My engine used to crank over so slowly until I added extrta earth straps from engine block to battery and extra body to battery earths. Now it cranks over flat out like it should. I wasnt actually saying that the earth fix doesnt work, I was just saying that the 02 sensors must be kept earthed to the engine block as well as adding the extra 02 earths to the body.. If its just earthed to the body the ECU sees big voltage variations in the 02 sensor readings and the fuel trims go way out..
The only time I havent seen the fix work was with the BSTK memcal problems as I mentioned above. The BSTK tune was apparently replaced by holden because of problems with cold hesitation and pinging, I wouldnt be revving my car when cold anyway to find any hesitation. Ive noticed that the ignition timing tables are set higher in this tune from the factory, so thats probably why it caused some pinging/knocking under load if the vehicle was only running on 91 octane unleaded..(which most would have been).
 
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