XJS V12 Unstable idle run
#21
I also purchased the repair kit on the E bay this morning, so as soon as this arrives I will hit the works, remove the AAV, clean it and repair, if needed, remount it and set the idle….hopefully it will help.
#23
I think all remarks regarding the AAV are appropriate but, considering the invasive nature of your previous work, I would suggest this, from Grant, as your first priority:
Throttle discs not set correctly, and the throttle rods not "balanced" correctly.
Cheers
DD
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#24
This is what Doug and others are talking about.
Ensuring those rods are reset, especially after all the dismantling you have done, is CRITICAL.
Disc gap at 0.002" wont change unless someone messes with the stop screws.
There are things in that attachment you will NOT need to do, or maybe there is, but the rods are covered, as is the disc gap.
Ensuring those rods are reset, especially after all the dismantling you have done, is CRITICAL.
Disc gap at 0.002" wont change unless someone messes with the stop screws.
There are things in that attachment you will NOT need to do, or maybe there is, but the rods are covered, as is the disc gap.
#25
This is what Doug and others are talking about.
Ensuring those rods are reset, especially after all the dismantling you have done, is CRITICAL.
Disc gap at 0.002" wont change unless someone messes with the stop screws.
There are things in that attachment you will NOT need to do, or maybe there is, but the rods are covered, as is the disc gap.
Ensuring those rods are reset, especially after all the dismantling you have done, is CRITICAL.
Disc gap at 0.002" wont change unless someone messes with the stop screws.
There are things in that attachment you will NOT need to do, or maybe there is, but the rods are covered, as is the disc gap.
thanks for the advises
I will check all this.
I post here under the video of the running- this is after start, when cold the engine runs high but regular (AAV open?), once motor heated up it goes like this up and down. Typical symptoms as you describe here above. No reaction on the Idle screw rotation.
This weekend I will take off the AAV out and test it. After that reset all parts carefully again….
to be continued
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Grant Francis (12-09-2022)
#26
As mentioned by many, your engines surges in idle simply due to getting too much air.
AAV is one of many potential sources to this excess air supply, and if you want to fix this in an efficient way you need to be smart.
All air supply should come from air boxes or vacuum lines. My suggestion: Start engine and pull off vacuum lines one by one and block the hole into the plenum with your finger. Next, remove air filters. Using a piece of tubing or hose, listen for suction noise at AAV hole and other holes connecting to the inlet plenums, or just try to block them using something, that will not be sucked into the engine. Hands/fingers will do the job 😉
Idle will drop when you block a significant contributor, and this way you can find the largest contributors to air supply and start out by fixing them.
In my case, with functional AAV, engine breather (PCV) was the sinner…
AAV is one of many potential sources to this excess air supply, and if you want to fix this in an efficient way you need to be smart.
All air supply should come from air boxes or vacuum lines. My suggestion: Start engine and pull off vacuum lines one by one and block the hole into the plenum with your finger. Next, remove air filters. Using a piece of tubing or hose, listen for suction noise at AAV hole and other holes connecting to the inlet plenums, or just try to block them using something, that will not be sucked into the engine. Hands/fingers will do the job 😉
Idle will drop when you block a significant contributor, and this way you can find the largest contributors to air supply and start out by fixing them.
In my case, with functional AAV, engine breather (PCV) was the sinner…
Last edited by leo_denmark; 12-09-2022 at 11:44 PM.
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Greg in France (12-10-2022)
#27
As mentioned by many, your engines surges in idle simply due to getting too much air.
AAV is one of many potential sources to this excess air supply, and if you want to fix this in an efficient way you need to be smart.
All air supply should come from air boxes or vacuum lines. My suggestion: Start engine and pull off vacuum lines one by one and block the hole into the plenum with your finger. Next, remove air filters. Using a piece of tubing or hose, listen for suction noise at AAV hole and other holes connecting to the inlet plenums, or just try to block them using something, that will not be sucked into the engine. Hands/fingers will do the job 😉
Idle will drop when you block a significant contributor, and this way you can find the largest contributors to air supply and start out by fixing them.
In my case, with functional AAV, engine breather (PCV) was the sinner…
AAV is one of many potential sources to this excess air supply, and if you want to fix this in an efficient way you need to be smart.
All air supply should come from air boxes or vacuum lines. My suggestion: Start engine and pull off vacuum lines one by one and block the hole into the plenum with your finger. Next, remove air filters. Using a piece of tubing or hose, listen for suction noise at AAV hole and other holes connecting to the inlet plenums, or just try to block them using something, that will not be sucked into the engine. Hands/fingers will do the job 😉
Idle will drop when you block a significant contributor, and this way you can find the largest contributors to air supply and start out by fixing them.
In my case, with functional AAV, engine breather (PCV) was the sinner…
And what about the Air injection system - you know the air pump, piping collector, funny small steel pipes introduced via the suction pipe to each cylinder head? Is there any leak possible? surely yes, But can it cause the problem?
I am asking because when I dismantled the engine the most of the small pipes was completely plugged, the steel tube air collector corroded with perforating holes, the back side check valve totally dead. I replaced and repaired all this, reinstall with new rubber seals, so now it is fully clean.
#28
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Grant Francis (12-10-2022)
#29
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