Holden VR v6 - vacumm testing for unsmooth idle

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Pete30nz
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Holden VR v6 - vacumm testing for unsmooth idle

Post by Pete30nz »

Hi there

Testing for vacumm leak with gauge. Havn't done the spray around manifold yet.
Chasing a rough idle, some times smooth on startup, other times rough.
When the vac line is unplugged from fuel reg, idles higher / smoother. When hooked back on fuel reg, it's a rougher idle.

I do have a vacumm guide picture of all the needle variants, but am new to this vacumm stuff to fully understand it.

Video attached. https://youtube.com/shorts/ua6LjF883yY?feature=share

Any help appreciated,

Cheers
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by yoda69 »

Common for fuel regulator to fail and leak fuel into the vacuum line.
If there is fuel in the vacuum line replace the regulator.
Pete30nz
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by Pete30nz »

Hi, I have been checking the fuel reg vac line, and I don't see any wetness. I do have an after market reg that could be fitted with attachments.
Pete30nz
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1996 VS v6 executive
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by Pete30nz »

Evening,
i'm still trying to track down a leak im guess, when i get around to it.

Aftermarket fuel reg was fitted after last message. how to know if its any good?

Tonight i replaced 2 o-rings from 2 injectors that were bad. which i found by spraying some carby cleaner around carefully.

Last night i replaced the 3 coils, the dfi module, and all spark plugs.
I have a new oxygen sensor to go in at some point.

Here is my data from this evening:


edit: also a screen shot
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antus
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by antus »

Just from that it looks ok, other than the o2 sensor not responding and probably causing that raw rich/lean to be lean (though not closely familiar with factory $11, so not sure what normal is). Under the Message 0 is there anything else there which you can use to see if there are any DTCs (errors) set?
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In-Tech
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by In-Tech »

Swap sides and if it follows, it's the sensor. Diagnose accordingly :)
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by vlad01 »

VR only has one sensor.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Pete30nz
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by Pete30nz »

antus wrote:Just from that it looks ok, other than the o2 sensor not responding and probably causing that raw rich/lean to be lean (though not closely familiar with factory $11, so not sure what normal is). Under the Message 0 is there anything else there which you can use to see if there are any DTCs (errors) set?
Yes to error code listing, no errors showing up yet. But when driving car to work, engine light had lit up, so not storing.?

INT was in the red, I think it was around 20.

Cheers
Pete30nz
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by Pete30nz »

Today I had another look under the bonnet, tracing vac lines. Blanced off the hose that went to the vacumm tank to eliminate the possibility of a bad tank. During this time also spraying some carby cleaner.
Listening to the revs pick up some, then drop again.
Still unsure exactly from where.

Car starts fine, 1500rpm then would settle to about 800rpm and sound semi smooth.
I noticed when revs are coming down from 1500 I can feel vibration/roughness.

Mostly it will settle at 700rpm and feel rough

Photos attached
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Pete30nz
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Re: Holden VR v6 - vacumm testing for unsmooth idle

Post by Pete30nz »

In-Tech wrote:Swap sides and if it follows, it's the sensor. Diagnose accordingly :)
That sounds ideal, but only the one oxygen sensor on here
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