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We have a VS V6 commodore which has a Miss. All sensors have been cleaned and tested, the car will accelerate if i do it extremely slowly but if i do it normally it will miss and backfire out the inlet. So i am thinking fuel supply or timing issue which is computer controlled. I've reset the computer but it is still doing it.
The car initially started to hesitate under acceleration but would eventually run well. Then it started to miss under acceleration and now its at its worse and we cant drive it.
The injectors have been cleaned and new o rings fitted, the fuel filter is clean, ignition leads, coil & dfi have all been swapped to known working ones so they are ruled out.
Which leaves fuel pump, regulator or computer.
Any other bright ideas?
I've posted this on afew forums to get a greater knowledge base.
Cheers Josh
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Cheers
Josh |
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Yep coils are all good, i should mention no logged codes either Edited by user Wednesday, 23 February 2011 12:10:47 AM(UTC)
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Cheers
Josh |
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Always a good idea to start at the start. Carry out a compression and cylinder leakage test. Possible valve problems.
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Hmmmm could be the sensor on the crank, from memory this can be a common problem. There is a simple test to rule it out but for the life of me i can't remember what it was :( Go over to the Just Commodores website and you'll probably find it there.
Hope that helps
Bill
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crank angle sensor plays up when the motor is warm, if you drive then turn it off it wont start until its cooled down, or put some cold water on it.
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in an older carby car sounds to me a bit like a vacuum leak somewhere, the mixture is a bit lean and hesitates when accelerating. whether that works with injection I don't know..does it idle a bit fast? is there wear in the throttle shaft?
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Idle is fine, no vac leaks that i can see or hear, i have sprayed water and some carb cleaner around in different spots on the engine where there may be a leak and the revs dont change. Thought we would bite the bullet and replace the Cas, went to undo the harmonic balancer bolt and it came undone by hand! Thats half the job done lol
On the other hand it is only pumping out 750ml of fuel in 30 seconds, it is meant to pump out 1.25Litres in 30 seconds. I have not been able to check the fuel pressure though as no one will lend me a tester.
Expensive bloody cars! Give me my old VC Commodore anyday! |
Cheers
Josh |
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It was the fuel pump, put a new one in it and it fired straight up into life. Thanks for the help fellas. We bought a Fuelmiser fuel pump, comes with a 2 year 40 000km warranty, i cleaned the tank out and the lines too. |
Cheers
Josh |
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You might have a broken outer valve spring.
Claude |
HG Monaros for ever!
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