WHY DOES MY ROUGH IDLE NOT CHANGE IF I DISCONNECT OR EVEN SWAP TWO OF MY LEADS

  • Tiny
  • kalickabie
  • 1998 Holden Commodore
  • 140,000 miles

I was silly and loaned my VS V6 Holden Commodore to someone. They decided to put 2 stroke fuel into it. It started running really rough almost straight away. When it was returned I was not told about the 2 stroke, as it was rough when I started it I straight away put injector cleaner and premium fuel in it thinking that it may have got some gunk in the lines. After a couple of days of it running roughly it decided not to run at all. I have replaced the fuel pump and filter, cleaned the tank out filled it up with more premium fuel and injector cleaner. I have changed the leads, spark plugs air filter, coil pack and TPS. After adjusting the throttle cable tension The car finally started again but idle really rough, and had to be started over and let idle for around 10 mins before the engine could be revved. When check again the spark plugs were completely black again, The have been change 3 times now. The car will drive but has no compression what so ever and when slowing down it will stall. It will go around 90kph tops and that is only in third gear sometimes if going down hill you can change into forth, never fifth gear. Even though there is plenty of spark going through the leads you can disconnect 2 leads leads, even swap them around and there is not even the slightest change in the idle. It seems no matter what I do The car just wants to run on 4 cylinders. Please help, what do I do?

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Monday, July 23rd, 2012 AT 9:01 AM

8 Replies

  • Tiny
  • Wrenchtech
  • Expert
  • 20,051 posts

Two stroke fuel is the same as regular fuel. It just has some oil mixed in with it and that will not harm anything. It may foul the spark plugs but no permanent damage. Get fresh fuel and a new set of spark plugs and you should be fine.

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Monday, July 23rd, 2012 AT 9:58 AM
  • Tiny
  • kalickabie
  • Member

The fuel is not really the problem it's just when the problems began. I did get new fuel injector cleaner, spark plugs leads coil pack throttle pressure sensor no matter what I do I can't get it to idle properly and run on more than 4 cylinders.

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Monday, July 23rd, 2012 AT 10:49 AM
  • Tiny
  • rivermikerat
  • Member

Your original post said that there was no compression. Was this tested with a gauge? Does squirting a little in the affected cylinders make any difference?

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Friday, September 7th, 2012 AT 2:31 AM
  • Tiny
  • georgebenson
  • Member

MAKE SURE U PROPERLY CHECKED COMPRESSION! BUT IM PRETTY SURE UVE GOT SOME PROB AS I DID 96 VS UR FLAT ELECTRONIC MODULE DIRECTLY UNDERNEATH UR 3 COIL PACKS TOP OF ENGINE IS SHOT OR TERMINALS HAVE CORROSION WHERE THEY HOOK INTO COIL PACKS I WAS DRIVING ON 4 CYLINDERS 4 A WEEK B4 I FOUND THAT OUT P.S. CHECK SPARK ON THOSE 2 LEADS FIRST.

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Sunday, September 16th, 2012 AT 9:15 AM
  • Tiny
  • rivermikerat
  • Member

I'm still waiting to hear about the compression test.

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Thursday, October 4th, 2012 AT 5:21 PM
  • Tiny
  • mhpautos
  • Expert
  • 30,561 posts

Do the comp test, these engines are also known for taking the top of cam lobes as well.

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Thursday, October 11th, 2012 AT 8:39 AM
  • Tiny
  • Wrenchtech
  • Expert
  • 20,051 posts

This poster hasn't responded to this question since July.

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Thursday, October 11th, 2012 AT 9:44 AM
  • Tiny
  • rivermikerat
  • Member

Maybe he fixed it and just doesn't want to tell anyone Wrench.

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Thursday, October 11th, 2012 AT 5:17 PM

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