Topic: Ruddy shaky idle - tracing it (Read 3608 times)

Diamond Black Geezer · « **on:** 20 June 2016, 09:41:22 »

So it's been months now, and dribs and drabs of searching lead me to nothing on the shaky idle front. However, the other day we find that after a run, parked waiting for a mate, find the idle is absolutely sewing-machine-style. As a rule it's better when warm.... and possibly gets worse when very hot, after the fans have cut in for a while. This suggests that it's linked to temperature, something expanding etc..

Vac tubes, elbows all fine. Still unsure about the scuttle vac tank, seems to be duff/dickey, (though this shouldn't affect the idle, just power delivery, yes?) Front vac tank works fine. Possibly worse in wet weather, too.

Really getting on my nerves now, because it's not helping economy, and sort of ruins what is an otherwise excellent drive. What the hell is it?

minifreek · « **Reply #1 on:** 20 June 2016, 11:09:30 »

Could be CTS faulty, thus making the ECU overfuel....?

Diamond Black Geezer · « **Reply #2 on:** 20 June 2016, 12:01:34 »

CTS? sorry, thats a new one on me, mate?

Nick W · « **Reply #3 on:** 20 June 2016, 12:39:53 »

Quote from: Diamond Black Geezer on 20 June 2016, 12:01:34

CTS? sorry, thats a new one on me, mate?

Coolant Temperature Sensor. That could cause poor economy, but won't affect the idle.
You're looking at an air leak or ignition fault. Ignition problems are always the place to start misfire diagnosis.

Diamond Black Geezer · « **Reply #4 on:** 20 June 2016, 13:23:44 »

Thanks minifreek, knowing how long you've spent on the V6s that's a sound bit of advice.

Igniiton should be ok. Plugs not too old, brand new leads, low mileage dis pack. Appreciate that it could be ignition. Have been thinking about the test the dis pack method actually. Though my spidey-senses tell me it's vac leak related, I won't dismiss it.

Take out a plug, then test with 35-40mm gap if memory serves, then continue unplugging and plugging in each respective 'socket' on the DIS pack with the same lead, yes? What's the 'best' point to hold the spark plug over, is there a convenient earth point?

Hoping it's not the CTS, I've just seen where that little sod is located!

Doctor Gollum · « **Reply #5 on:** 20 June 2016, 13:29:40 »

Discounted pack

Diamond Black Geezer · « **Reply #6 on:** 20 June 2016, 13:38:27 »

Sorry, I seem to not be understanding English today!

'Discounted pack'

Entwood · « **Reply #7 on:** 20 June 2016, 13:41:06 »

Quote from: Diamond Black Geezer on 20 June 2016, 13:38:27

Sorry, I seem to not be understanding English today!

'Discounted pack'

I think he means "I have discounted the pack as the cause of the problem" ... but I could be wrong !!

tigers_gonads · « **Reply #8 on:** 20 June 2016, 13:49:35 »

Give us a shout when your free and i'll plug the laptop in and check both temp sensors are reading about the same and look at other things for you

Doctor Gollum · « **Reply #9 on:** 20 June 2016, 13:54:59 »

Quote from: Doctor Gollum on 20 June 2016, 13:29:40

Discounted pack

Dis pack stupid poxy aurocorrect

Diamond Black Geezer · « **Reply #10 on:** 20 June 2016, 14:19:53 »

Ahhh, all understood, now!

Cheers Steve, I'll let you know, though I am under instructions from Bekki you're not to try and reprogram anything, she's concerned about the ECU being wiped by your well-meaning man hands. I have told her men aren't all like me, breaking everything I intend to mend!

So Mr Smeegle reckons DIS pack?

Entwood · « **Reply #11 on:** 20 June 2016, 14:26:53 »

Quote from: Doctor Gollum on 20 June 2016, 13:54:59

Quote from: Doctor Gollum on 20 June 2016, 13:29:40
Discounted pack
Dis pack stupid poxy aurocorrect

OK .. I was wrong ..

tigers_gonads · « **Reply #12 on:** 20 June 2016, 14:33:37 »

Quote from: Diamond Black Geezer on 20 June 2016, 14:19:53

Ahhh, all understood, now!

Cheers Steve, I'll let you know, though I am under instructions from Bekki you're not to try and reprogram anything, she's concerned about the ECU being wiped by your well-meaning man hands. I have told her men aren't all like me, breaking everything I intend to mend!

So Mr Smeegle reckons DIS pack?

Nah, TuBy filled me full of horror stories about what can happen when you try and reprogram things with "My Naff Code Reader"

I've had nightmares ever since

Oh by the way, tell the lovely Becky i'll be around there to shown her my new manual gearstick fitted to my full fat v6

You can play with the laptop

While I remember, what type of socket is it on the coil pack ?
Check the MAF plug for a clue because i've a couple of oval DIS packs here if needed

Diamond Black Geezer · « **Reply #13 on:** 20 June 2016, 15:34:55 »

Oval. Appreciate the offer. Have a brand new one in the box, arrived a few days ago. I got it as a spare in the long, distant future, not expecting any issue with the DIS pack for a long time!

minifreek · « **Reply #14 on:** 20 June 2016, 16:07:17 »

I think, with the aforementioned bad fuel economy, it'll be the CTS...

Mine had a bad shudder, and hunting at idle, and that turned out to be the CTS....

This was all after changing the dispack, Idle Control Valve and the complete ignition system, including a new set of plugs...

The dispack, if it was starting to break down, would give a misfire and keep misfiring all through the rev-range, not just at idle...

If I'm wrong and it does turn out to be the dispack, then I'll hold my hands up....

Diamond Black Geezer · « **Reply #15 on:** 20 June 2016, 16:28:29 »

Sadly nothhing to compare bad fuel economy with, really, she's always been about this - about 'notch' below what the computer claims I should be doing. I seem to be at 3.0 levels of mpg, while enjoying 2.2 levels of performance!

tigers_gonads · « **Reply #16 on:** 20 June 2016, 18:58:01 »

Quote from: Diamond Black Geezer on 20 June 2016, 15:34:55

Oval. Appreciate the offer. Have a brand new one in the box, arrived a few days ago. I got it as a spare in the long, distant future, not expecting any issue with the DIS pack for a long time!

Might be down your way this Sunday if the weathers okay for the forces weekend.
You have my number

Diamond Black Geezer · « **Reply #17 on:** 21 June 2016, 10:43:25 »

Thanks young fellermelad

We're thinking of doing soem Armed Forces bits on the Friday night, then leaving up-the-drive car jobs for Sat (with all the roads closed off, traffic a nightmare etc) then out and about watch some more Armed Forces Day celebrations on the Sunday.

WIll be looking into all aspects, the ignition but also the CTS, sounds like this could be the winner

Doctor Gollum · « **Reply #18 on:** 21 June 2016, 12:42:11 »

Live data will confirm the CTS function... ecu temp should be broadly similar to what the gauge is saying

Re performance, are the multirams working as advertised $:-\$

Diamond Black Geezer · « **Reply #19 on:** 21 June 2016, 13:41:40 »

Front, yes, just over 3k, rears, after a quick, hefty blip the rear did move some, too. But I do think there's a flat spot - or specifically a slight 'surge' in power over 4k when giving it the Heinz.

One of my thoughts is that if the top hat seal is knackered, this would be weeping air from one side to the other, surely. There does seem to be a fair appreciable 'woosh' when you hold your ear to the plenum. I think it's louder than it was a year ago, but not easy to tell, as you can image.

Marks DTM Calib · « **Reply #20 on:** 21 June 2016, 14:58:25 »

Quote from: Diamond Black Geezer on 21 June 2016, 13:41:40

Front, yes, just over 3k, rears, after a quick, hefty blip the rear did move some, too. But I do think there's a flat spot - or specifically a slight 'surge' in power over 4k when giving it the Heinz.

One of my thoughts is that if the top hat seal is knackered, this would be weeping air from one side to the other, surely. There does seem to be a fair appreciable 'woosh' when you hold your ear to the plenum. I think it's louder than it was a year ago, but not easy to tell, as you can image.

Have you still not fixed that?

Diamond Black Geezer · « **Reply #21 on:** 21 June 2016, 15:43:03 »

I got diverted onto other things, sadly.

Right, I'm off to put a wanted ad up

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Author Topic: Ruddy shaky idle - tracing it (Read 3608 times)