Have run out of ideas.
07-16-2015, 01:01 PM
#21
Staging Lane
Join Date: Aug 2014
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I would bet my tires it's an o2 sensor. I had the same thing happen to me after it developed a miss and an exhaust leak last october.
Car showed a massive amount of misfires on Cylinder 6. Cylinders 2, 4, and 8 showed a bit but not nearly as many. Did compression, plugs, injectors, coil pack. Everything was fine.
Swapped the o2, ran like a champ.
The reason why the car runs fine in open loop is it's running on pre-set ignition tables. But as soon as closed loop hits your o2 sensor is saying either it's super lean or rich, and the car is trying to adjust. (In my case it was saying lean so I was dumping fuel down the exhaust pipe. Fouled up my cats ><). if you want to test before buying the sensor, try swapping it to the other side (make sure to use plenty of anti-seize) and see what happens.
Car showed a massive amount of misfires on Cylinder 6. Cylinders 2, 4, and 8 showed a bit but not nearly as many. Did compression, plugs, injectors, coil pack. Everything was fine.
Swapped the o2, ran like a champ.
The reason why the car runs fine in open loop is it's running on pre-set ignition tables. But as soon as closed loop hits your o2 sensor is saying either it's super lean or rich, and the car is trying to adjust. (In my case it was saying lean so I was dumping fuel down the exhaust pipe. Fouled up my cats ><). if you want to test before buying the sensor, try swapping it to the other side (make sure to use plenty of anti-seize) and see what happens.
09-18-2016, 06:59 AM
#22
Teching In
Join Date: Nov 2015
Location: Yeppoon Qld Australia
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Here is another idea.
I was getting a very similar problem with my LS1 /94 Suburban until I opened up the coil pack harness and found what look like a pinched/ broken earth wire (black).
I carefully unpicked the harness and resolderd a new piece back in , covered with heat shrink and refitted. I tested for resistance and took it for a spin.
I test drove in the rain today and it feels like I have fixed it.
I think the reason it happened is the engine covers are usually forced gently into position , without any thought of the long term effects of the harness underneath.
I was getting random missfire codes too ....partially separated earht wire would allow this to happen...(hit and miss), potholes etc.
Just my 2 cents.
Ozzie Bob
I was getting a very similar problem with my LS1 /94 Suburban until I opened up the coil pack harness and found what look like a pinched/ broken earth wire (black).
I carefully unpicked the harness and resolderd a new piece back in , covered with heat shrink and refitted. I tested for resistance and took it for a spin.
I test drove in the rain today and it feels like I have fixed it.
I think the reason it happened is the engine covers are usually forced gently into position , without any thought of the long term effects of the harness underneath.
I was getting random missfire codes too ....partially separated earht wire would allow this to happen...(hit and miss), potholes etc.
Just my 2 cents.
Ozzie Bob
09-18-2016, 07:46 AM
#23
Whats the condition of the gas? old? water in fuel? Drain some out off the fuel rail into a clear bottle, and see what it looks like.
Random miss fire that's not spark related, could need the fuel injectors cleaned.
With something like this, not a can of cleaner you put in the fuel tank. This goes straight in the fuel rail and cleans the injectors. Fantastic tool
http://www.etoolcart.com/images/prod.../OTC7448.1.jpg
Kyle
Random miss fire that's not spark related, could need the fuel injectors cleaned.
With something like this, not a can of cleaner you put in the fuel tank. This goes straight in the fuel rail and cleans the injectors. Fantastic tool
http://www.etoolcart.com/images/prod.../OTC7448.1.jpg
Kyle
Last edited by Lup; 09-18-2016 at 07:52 AM.
09-21-2016, 04:53 PM
#24
On The Tree
Join Date: Apr 2012
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Hey, just out of curiosity, have you checked your battery and your alternator? It may be worth a shot.
Also, have you considered draining your fuel tank and trying fresh gas? It sounds like you do a great job of maintaining your fuel, but, again, this may be worth a shot.
Lastly, have you checked your fuel filter?
Best of luck!
Also, have you considered draining your fuel tank and trying fresh gas? It sounds like you do a great job of maintaining your fuel, but, again, this may be worth a shot.
Lastly, have you checked your fuel filter?
Best of luck!