Dual Mass Flywheel Test can anyone help

Ask for and share advice on using the PicoScope kit to fix vehicles here.

Dual Mass Flywheel Test can anyone help

Postby RYM6746 » Fri Jul 07, 2017 12:42 am

Hi All, I have a Nissan X trail 2.2D denso system with 144000 miles, which has an engine wobble at idle ONLY. It's not a misfire. Car has no fault codes. EGR is ok. Rail pressure at idle is ok. Can't do injector leak off easily as leak of pipes are under cam cover and come out as a single pipe. No starting issues. Wouldn't even really call it a rough idle. It just wobbles the whole car (most noticeable when bonnet is up as it wobbles that about) so my suspicions are maybe a DMF issue but I am certainly not going to whip the gearbox out on a hunch. So my million dollar question is does anyone know how to test for a faulty DMF using the pico on maybe the crank sensor. Or any sensor in fact. I need a reliable test to eliminate or condem the fly wheel with out gearbox removal? ???? If there is such a test.??
User avatar
RYM6746
TwoWaves
TwoWaves
 
Posts: 99
Joined: Tue Nov 01, 2016 10:58 am

Re: Dual Mass Flywheel Test can anyone help

Postby STC » Fri Jul 07, 2017 10:49 am

Can't do injector leak off easily as leak of pipes are under cam cover and come out as a single pipe

You can with WPS on single pipe and amp clamp on Injector 1. Steve Smith has done a video on this

Smooth Running Values ??

Scope on Crank Sensor, RPM Math Channel and bring the clutch to biting point slowly.

Would the NVH kit help with this ??
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Dual Mass Flywheel Test can anyone help

Postby Dcunning35 » Fri Jul 07, 2017 8:38 pm

I agree with stc if this is more a vibration ,boom the nvh kit would probably be best suited but I have never used it and couldn't really advise on its use.
The old favourites clutch depressed , maybe look for ckp erraticsms or ive seen torque and boost reduction on the fords when dmf is out of balance .
Good luck buddy.
Dcunning35
TwoWaves
TwoWaves
 
Posts: 190
Joined: Thu Jan 28, 2016 2:33 pm

Re: Dual Mass Flywheel Test can anyone help

Postby STC » Sun Jul 09, 2017 12:52 am

It's not a misfire. Car has no fault codes

I have in my possession an Astra J 1.7CDTi 2011. The block and cylinder head between cylinders 3 & 4 have been destroyed. I needs a new engine ... Period !

Prior to taking the head off it had near zero compression on 2 cylinders yet no fault codes using genuine GM MDi diagnostic tooling.
Smooth running values ?
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Dual Mass Flywheel Test can anyone help

Postby RYM6746 » Sun Jul 09, 2017 3:22 pm

The only scan tool I have that will communicate with the X trail is the Bosch KTS and it has no smooth running value data parameter for that specific ECU. I have AC coupled the rail pressure sensor and all the humps and dips are relatively even (nothing stands out ) It has NO lack of power and as soon as you take it 100rpm off of idle the wobble has gone. You can however see a classic sticking fuel pressure regulator in the overall WOT rail pressure profile. Which will need attention but at idle the pressure is good and even yet the wobble is present. With the scan tool you can command the regulator to different positions and the note of the engine changes along with the pressure but it has zero effect on the wobble. I will put a new regulator in and see if it has any effect but I doubt it will. But it does need changing as you get the classic dips in pressure as the pressure rises and the pressure actually goes slightly below what it was originally when coming back to idle. I will try to upload waveform when I back at work
User avatar
RYM6746
TwoWaves
TwoWaves
 
Posts: 99
Joined: Tue Nov 01, 2016 10:58 am

Re: Dual Mass Flywheel Test can anyone help

Postby STC » Sun Jul 09, 2017 8:29 pm

Do you have or can you capture CKP with a good few engine rotations across the screen with the vibration present.
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Dual Mass Flywheel Test can anyone help

Postby RYM6746 » Mon Jul 10, 2017 3:32 pm

Unfortunately car has gone at the moment due to the owner being abroad and the father who brought it to us not being able to contact him. As soon as I see it again I will try to get the CKP capture for you.
User avatar
RYM6746
TwoWaves
TwoWaves
 
Posts: 99
Joined: Tue Nov 01, 2016 10:58 am

Re: Dual Mass Flywheel Test can anyone help

Postby RYM6746 » Mon Jul 10, 2017 3:41 pm

Here is the rail pressure WOT profile. What are your thoughts on the surges at high pressure and the different pressures at idle? There is only one WOT and starting event. The rest of the time it was idling and it looks to me like it was struggling to maintain pressure
Attachments
Nissan_X-Trail_2004_Diesel_Fuel pressure WOT BAD.psdata
(1.08 MiB) Downloaded 26 times
User avatar
RYM6746
TwoWaves
TwoWaves
 
Posts: 99
Joined: Tue Nov 01, 2016 10:58 am

Re: Dual Mass Flywheel Test can anyone help

Postby STC » Thu Jul 13, 2017 1:00 am

The same capture with APP on channel 2 would be nice.

I don't see that it is struggling to maintain pressure ?

It gets from zero to start pressure in 500 ms of cranking which is not bad, then it settles. WOT it peaks at 3.6v then maintains 2.4v down to steady 1.6v. What is not to like about that ?

However I can see the difference before and after the WOT event. Perhaps double the amount of time across the screen and allow the engine to idle for longer before WOT. Just to see that it has settled at its idle speed.

Does KTS have Actual & Desired Pids for this, if yes then graph them zoomed in at 60 seconds, that should paint you a pretty picture.
User avatar
STC
TwoWaves
TwoWaves
 
Posts: 790
Joined: Sun Sep 13, 2015 4:10 am

Re: Dual Mass Flywheel Test can anyone help

Postby RYM6746 » Thu Jul 13, 2017 10:56 pm

I am basing my faulty regulator on the pressure decreases in the rising event and the fact that it should not allow pressure to go below what it was before you opened the throttle and every other system I have seen doesn't take 3 whole seconds to reach a comfortable idle pressure. Here is a transit that I fixed by replacing the regulator look at the before and after of the WOT profile nice clean cut pressures with new regulator fitted. Maybe I am just over analysing an un familiar system but the transit is also a denso with one regulator
Attachments
Ford_Transit_2008_Diesel_Rail pressure WOT good.psdata
(603.49 KiB) Downloaded 12 times
Ford_Transit_2011_Diesel_Rail press from idle to WOT faulty press reg BAD.psdata
(5.22 MiB) Downloaded 10 times
User avatar
RYM6746
TwoWaves
TwoWaves
 
Posts: 99
Joined: Tue Nov 01, 2016 10:58 am


Return to Diagnostic discussion

Who is online

Users browsing this forum: No registered users and 0 guests