Heavy vibration under load between 1500-2000rpm Diesel

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RMdiagnostics
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Posts: 1
Joined: Thu Dec 10, 2020 1:34 pm

Heavy vibration under load between 1500-2000rpm Diesel

Post by RMdiagnostics »

Goodmorning fellow Pico users and staff,

I was hoping to get some insight on these captures. First i like to start by introducing myself. My name is Roy. I'm a mobile diagnostician which is quite rare here in holland. I decided about a year ago i would like to add NVH diagnostics as a part of my services and purchased the starterkit. Used it about 4 to 5 times now. This time i was hoping to also finish with a vibration free result with the help of you all. Now back to the case i'm currently working on:

2017 Ford Transit 330 2.0 Diesel with a manual 6-speed transmission FWD LHD
History, all from the shop owner:
Van came in with a problem on 1 of the injectors. Couldn't get it out of the cylinderhead and because these engine are known for failing they decided to fit a new engine in it. What i've been told that new is a barely used engine. it looked new and it came with all the accessory's mounted on it. After replacing the engine the customer came back after a little while with a complaint about heavy vibration when accelerating between 1500-2000rpm. Really heavy and the higher the gear the more heavy it gets. The steering wheel shakes and sometimes the tachometer drop's out due to vibrations.(lost communications with ecm codes are set only in the cluster after this happens.)
I'm not sure of this is the right order of events but this has been replaced in an attempt to fix it:
All engine mounts with aftermarket ones
The right(long) driveshaft also aftermarket
with no avail.
the customer really needed the van since it is a rental vehicle but after about 15.000km the car broke down. there was no acceleration possible. The dual mass flywheel spins freely.
The dual mass flywheel got replaced with a good brand aftermarket one which also greatly improved the vibration. There was still a little vibration going on but it was acceptable according to the shop. Until the history repeated. The vibration got worse over time and eventually the flywheel broke down again in the same way. it got replaced, same story, Vibration improved, untill now again the vibration is really heavy. At this point i got a call if i was willing to have a look at it. Sounded like a great opportunity to use the NVH kit.

Where i'm at now: Took it for a test drive with the magnet mounted to the driver seat rail (which is left side of vehicle here). I noticed a lot of T3 vibrations and E1. When cornering the driveshaft was noticable shaking and since i could find no other explanation for the T3 than the left drive shaft with a tripod joint we decided to replace it. It greatly improved the symptom but it's kind of hard to tell because the van also started to give some warning lights about the DPF needed a clean. Not sure yet if it's was in reduced torque mode all of a sudden because of this or that the drive shaft really fixed something. The shop is gonna do a forced regeneration and try again to be sure. What i've noticed is that there are mainly some E1's left. The flywheel again? My theory right now is as follows: "Maybe the tripod joint got damaged during the engine replacement and started this vibration which damaged the dual mass flywheel(not sure if it's possible). The vibration greatly improved everytime the flywheel got replaced and improved now that left driveshaft is replaced. The van is still left now with a damaged flywheel due to the miles driven with the driveshaft. This flywheel needs to be replaced(E1's) and then it will be all good." Not completly convinced yet and that's when i decided to start a topic here.

What are you're opinions? is this enough information?

I added 3 files: 'T3 vibration' is one of the first drives. 'Heavy Vibrations' is when the tachometer drops out. And the last one speaks for itself.

So to be clear about the complaint:

it shakes in 4,5,6 gear between 1500-2000rpm only on heavy acceleration. when you drive through this range on light throttle you feel barely anything.

Kind Regards,

Roy
Attachments
T3 vibration.pddata
(4.15 MiB) Downloaded 25 times
Heavy Vibration.pddata
(3.65 MiB) Downloaded 42 times
After replacing left driveshaft.pddata
(4 MiB) Downloaded 26 times

ben.martins
Pico Staff Member
Pico Staff Member
Posts: 550
Joined: Tue May 16, 2017 1:02 pm

Re: Heavy vibration under load between 1500-2000rpm Diesel

Post by ben.martins »

Hi Roy,

Thanks for sharing this and it seems that this case has got very involved!

That being said, it is a perfect opportunity for the Pico NVH kit as you say. Looking back through the history it has had a lot going on. Thank you for capturing this as I know it can take time.

Looking through the captures we have to be careful due to the close proximity with E1 and T3. I would agree that replacing the driveshaft has reduced the vibration but it is clear that this frequency is still dominant. One way to try and prevent the confusion is keeping the vehicle in a gear where the engine speed can still be maintained to capture the vibration but the wheel speed is very different.

For an E1 order we are seeing a vibration/shock occur once for every one rotation of the crankshaft. We need to mindful here that this can also include pulleys of the same size which will rotate at the same speed as the crankshaft. One area that I would be looking at is the harmonic balancer or crankshaft pulley. A failed harmonic balancer would cause excessive first order engine speed related vibration.

Now, whether this can cause the other issues with the flywheel I'm not sure. I'm less likely to place the E1 vibration and the DMF at the cause of the driveshaft failure as well suspecting some issue during the engine replacement the more likely cause. Nothing is impossible though. With regards to the DMF, do you feel any vibration if you lightly rest your foot on the clutch pedal?

I think it is important to also understand what is happening during the high engine load. Maybe capturing some serial data at the same time focusing on injectors, engine speed and fuelling. You could even switch out the NVH to the scope and pick up the crank sensor with an injector sync to cyl 1 (or camshaft) and just make sure the engine is behaving, no misfires, over fuelling etc. To be clear, a misfire would create a E0.5 vibration (combustion only occurs every 2 times the crank rotates for one cylinder so a single cylinder misfire would create a E0.5 vibration in a 4 stroke engine).

I think it's key to also understand why the tacho drops out. Just wondering if it's an idea to check the harness, make sure it's not pinched anywhere and routed correctly.

Lots to think about but I'm not sure at this stage that a new DMF will resolve the issue.

I'm sure others will have some insight and advice on this subject but I hope this helps for the time being.

Kind regards

Ben

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