Technical 2.4 Noisy Engine, opinions?

[danhans115]

About a week ago my engine was running whilst I was parked, next thing I know the car stalled and wouldnt start. To cut a long story short the variator had completely failed, as in you could actually turn it with your hand, and in doing so shredded the cambelt and it jumped one tooth on the inlet side.

Anyway, luckily the garage is just literally 50 metres from where I was parked so we rolled the car down there.

They have compression tested the engine, all fine. Everything seems to be okay apart from there is a loud 'diesel on a cold morning' sort of noise when the the engine revs drop off. Revving up is fine.

Anyone any ideas, they are doing it for me around other jobs, as mates rates as well but Ive been carless for a week now and wondered if anyone here had any ideas?

Thanks

Dan

 

[Greggers]

About a week ago my engine was running whilst I was parked, next thing I know the car stalled and wouldnt start. To cut a long story short the variator had completely failed, as in you could actually turn it with your hand, and in doing so shredded the cambelt and it jumped one tooth on the inlet side.

Anyway, luckily the garage is just literally 50 metres from where I was parked so we rolled the car down there.

They have compression tested the engine, all fine. Everything seems to be okay apart from there is a loud 'diesel on a cold morning' sort of noise when the the engine revs drop off. Revving up is fine.

Anyone any ideas, they are doing it for me around other jobs, as mates rates as well but Ive been carless for a week now and wondered if anyone here had any ideas?

Thanks

Dan

Hmmmm... don't want to be negative and I hope I'm wrong but it could be the conrod bearings on the way out. Usually the big end bearings rumble under load and the little end bearings rattle when the load is released. Hopefully it's just your variator though!

 

[Yellow Peril]

That sounds like classic failed Variator noise. I'd assumed from your story that the first thing the garage would have done was to replace the variator (and cam belt obviously). Did they?

 

[danhans115]

Thanks for the replies guys. The mechanic is saying the noise is definately coming from the variator,not the bottom end.

Yeah hes changed the variator for a brand new one, along with a brand new cambelt kit. The belt/pump/tensioner were changed at 63k 2 years ago, the car now has 74k on it.

I have the old variator at home, the internals gearing is stripped bare almost and its a bit of a mess so it was definately the variator that failed, but leading up to this it never showed any of the normal signs of failure.

Im thinking now I wonder if it could be the solenoid thats dodgy?

 

[Yellow Peril]

There's some tips here:

https://www.fiatforum.com/stilo/160084-variator-info-all-you-vari-haters.html

on how to check if it's the solenoid at fault.

 

[danhans115]

I came onto that from google and passed that onto the garage along with some diagrams from EPER. I think im really getting on the mechanics nerves now lol.

Ill have to see what they come back with later.

 

[Greggers]

Im thinking now I wonder if it could be the solenoid thats dodgy?

The solenoid only kicks in at about 3500rpm and activates the variator until about 4750rpm (or something like that...) There's a couple of tests you can do to prove the correct operation of your variator.

1) To test the solenoid: What you're trying to do is to test the variator solenoid, and it's easy to diagnose, just put your multimeter across the 2 terminals of the solenoid (the blobs on the top, not the plug connectors) and check for continuity, if there's none (eg. you've got some resistance there) then undo the 2 philips screws on the top of it and remove the cap (pull it off, don't twist), connect the multimeter to the 2 spikes on the solenoid and check for continuity again, I bet you get it this time. if you do then it's the cap at fault, what you need to do is drop little balls of solder into the 2 holes for the spikes in the cap and then fit it back on, then you should have your continuity back accross the plug terminals. If you didn't have continuity across the cap and the actuator pins, then the actuator is probably at fault and you'll need to get it replaced.

2) To test the ECU: Take the plug off the solenoid and connect a multimeter to the socket of the plug. There's three there and I can't remember which ones you need to test but essentially, what your trying to do is is see if the ECU changes the voltage across the two of the pins when the engine goes through the rev range. At idle until about 3500rpm, there should be 0volts. At 3500-4750rpm, there should be 12v and from 4750 to redline, there should be 0v. If you see that happen, then the ECu is okay

3) To test the Variator: The solenoid has a permanent 12v on one of the pins it but the other pin is only grounded by the ECU when the variator is to be actuated. This means that you can test the solenoid by grounding one of the terminals (the bottom terminal I think, test this yourself by using the multimeter and testing the voltage between the chassis and each solder blob on the top of the solenoid cap. Whichever doesn't give you a voltage reading, is the one you want to ground). So... with the engine running, briefly touch a wire between the chassis and the solder on the cap that is supposed to be grounded by the ECU.

If everything is working as it should in the solenoid and the variator then the engine should almost stall straight away. This is because the variator has altered the inlet valve timing at idle meaning that the inlet valve is open at the wrong time messing with the compression and ignition.

 

[danhans115]

Thanks for the replies.

Hes going to check the solenoid today - so fingers crossed its that.