Technical It started with a big ol' clonk...
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Technical It started with a big ol' clonk...
Thanks for the clarification!
(The last digit (the 6) on the Current P/N might be a typo.)
Ooops typo by me, should read:
Current Part No: 71736025 - 07/07/2003
Previous P/N: 5896137 - 07/06/1995
Previous P/N: 60811321
Indeed, apologies - 71736026 is a rear seat headrest for a Palio
Update...:
I (finally) got MES connected and it in turn had the solenoid relay happily clicking away.
Next I checked the solenoid resistance, I got 15 ohms. I wonder how that compares to a healthy one... If the resistance checks out I'll pull out the solenoid+valve to look for actual valve movement while activating the s. relay.
I (finally) got MES connected and it in turn had the solenoid relay happily clicking away.
Next I checked the solenoid resistance, I got 15 ohms. I wonder how that compares to a healthy one... If the resistance checks out I'll pull out the solenoid+valve to look for actual valve movement while activating the s. relay.
It seems MES won't activate the different functions when the engine is running. So my point 2 above using MES won't work.
Searching around a bit I found that 12/13 Ohm is a reported solenoid value, so my 15 Ohm is at least ballpark. I'll do some more electrical testing before tearing the solenoid+valve out, there is no oil leak from it currently, and it is apparently quite common, so I'd prefer leaving it be (if possible).
New 2:
2.1 test for current from the relay when over 1700rpm.
2.2 test for continuity between pins in socket and solenoid top soldering points
2.3 activate the solenoid with the engine off, through connecting one of the soldering points to earth, and listen for faint click
2.4 activate the solenoid when idling, which should result in rough idling and maybe the rattle
If all checks out (including 2.4 with rattle) then order some Wynn's and on to Point 3.
New 4, a Volvo YouTuber has claimed some success cleaning a VVT valve from oil deposits by sticking it in some cleaner, I might try that if 3 fails.
Update2
Did Number 3; filled a can of Wynn's Hydraulic Valve Lifter Treatment (into the old sump), attached the Variator Solenoid cable, and... the Variator rattles consistently when activated between 1700-4700rpm. To be fair the Wynn's fluid has not been sloshing around for very long, but took the b on a 20 min drive, much of the time in the Variator activated rpm-range and the rattle is painful to hear. Will probably be declaring No. 3 a failure soon and getting ready for No. 4.
Did Number 3; filled a can of Wynn's Hydraulic Valve Lifter Treatment (into the old sump), attached the Variator Solenoid cable, and... the Variator rattles consistently when activated between 1700-4700rpm. To be fair the Wynn's fluid has not been sloshing around for very long, but took the b on a 20 min drive, much of the time in the Variator activated rpm-range and the rattle is painful to hear. Will probably be declaring No. 3 a failure soon and getting ready for No. 4.
Looks like you will have to get the variator repair kit and try that.
https://www.partsworld-uk.com/products/cam-variator-spring-kit
Thanks, I don't know diddly-squat about variators, but isn't this spring kit useful for the rpm-range where the variator is not activated (by oil pressure), ie idle-1700rpm and 4700-and above? In my case the variator is "silent" in this range. The range where I get the clatter 1700-4700rpm is where/when the solenoid should have the oil pressure pressing against the variator spring and thus causing the phase variance. To me a failing solenoid, solenoid valve, and/or clogged oil channel causing weak oil pressure is the culprit. What am I missing?
Sort of understand what you are saying.
Have you downloaded the Barchetta Service Manual for this website? I has a reasonably detailed technical explanation of the whole variator operation etc.
It could be that you variator is just mechanically worn out? Or are you hearing excessive tappet noise at higher RPMs? By this I mean that as the variator operates it puts the cam timing and this "lift" by angle into a different range that is creating more valve noise?
All the above is just my thoughts based on no specific personal experience with diagnosing variator faults/noise/etc.
Duh, thanks, excellent point. I feel a bit silly, I have the manual, but have not gone through the variator section carefully lately. It all started out with me thinking the problem was something completely different....Sort of understand what you are saying.
Have you downloaded the Barchetta Service Manual for this website? I has a reasonably detailed technical explanation of the whole variator operation etc.
It could be that you variator is just mechanically worn out? Or are you hearing excessive tappet noise at higher RPMs? By this I mean that as the variator operates it puts the cam timing and this "lift" by angle into a different range that is creating more valve noise?
All the above is just my thoughts based on no specific personal experience with diagnosing variator faults/noise/etc.
Appreciate your thoughts!
Concerning wear, maybe but it is not obvious to me, as the (impossible to miss) clatter, is silent below and above 1700-4700rpm. The clatter will not appear (at all) in the 1700-4700rpm range when the electric lead to the solenoid is disconnected.
I didn't get to hear it myself, but there was some type of clonk in connection with when the clatter started showing its ugly face (in the 1700-4700rpm range). Assuming it is correct this would point towards some type of failure (as compared to an oil channel getting clogged).
Went through the BSM concerning the variator, it unfortunately left me not all that much wiser... From the sound of it the relay is working, so it "should" be down to four possible issues:Sort of understand what you are saying.
Have you downloaded the Barchetta Service Manual for this website? I has a reasonably detailed technical explanation of the whole variator operation etc.
It could be that you variator is just mechanically worn out? Or are you hearing excessive tappet noise at higher RPMs? By this I mean that as the variator operates it puts the cam timing and this "lift" by angle into a different range that is creating more valve noise?
All the above is just my thoughts based on no specific personal experience with diagnosing variator faults/noise/etc.
1- The electro-magnet/solenoid
2- Oil channels
3- (Counter springs)
4- Mechanical fault
1- The clatter does happen with would indicate solenoid full or partial movement
2- The variator has plenty of oil channels that can get clogged and cause havoc, but not the claimed starting clonk.
3- It seems the two springs (solenoid valve and variator) are ok, as the engine is clatter free over and under 1700-4700rpm.
4- a Mechanical fault eg piston and/or pinion would perhaps cause the first claimed clonk, but a hindered movement should cause issues over and under 1700-4700rpm.
Still voting for clogged oil channels and/or the solenoid valve issue and/or a partially moving solenoid...
What say ye?
Thanks,
T
Update:
Gah, I was barking up the wrong tree...
The fault turned out to be a loose cam belt due to an incorrectly adjusted tensioner (and the timing perhaps being off).
Still I decided to follow through and went on to disassemble the variator and run air through the oil ducts to the variator actuator. I found no apparent damage or clogging.
I redid the timing using after market cam locks and using the upper fly-wheel mark (removing the battery and battery tray makes line of sight easier). I released both the inlet and exhaust cogs, the latter is not mentioned in the service manual for the barchetta, but a Portugese gentleman describes it very well for the Alfa/Pratola-Serra B engine here:
Following his instructions made it easy to re-mount the cam belt and get the timing pretty much correct (I did not have/use the crankshaft lock/adjustment tool).
(The driving pulley was incorrectly mounted, the pulley hole and the crankshaft bump were not mated)
After three test drives w engine temp >40°C and rpm >3000 WITHOUT engine rattle I happily declare the problem SOLVED (until further notice)!
Thanks to all who have partaken!
(The hunting idle threatening to stall at the traffic light is also gone.)
Gah, I was barking up the wrong tree...
The fault turned out to be a loose cam belt due to an incorrectly adjusted tensioner (and the timing perhaps being off).
Still I decided to follow through and went on to disassemble the variator and run air through the oil ducts to the variator actuator. I found no apparent damage or clogging.
I redid the timing using after market cam locks and using the upper fly-wheel mark (removing the battery and battery tray makes line of sight easier). I released both the inlet and exhaust cogs, the latter is not mentioned in the service manual for the barchetta, but a Portugese gentleman describes it very well for the Alfa/Pratola-Serra B engine here:
Following his instructions made it easy to re-mount the cam belt and get the timing pretty much correct (I did not have/use the crankshaft lock/adjustment tool).
(The driving pulley was incorrectly mounted, the pulley hole and the crankshaft bump were not mated)
After three test drives w engine temp >40°C and rpm >3000 WITHOUT engine rattle I happily declare the problem SOLVED (until further notice)!
Thanks to all who have partaken!
(The hunting idle threatening to stall at the traffic light is also gone.)
This should be the simplest way to make a comparison by disconnecting the electrical lead to the variator actuator/solenoid.
Disconnecting it will not throw a code.
The variator is claimed to engage in the range 1.700-4.700rpm.
A 0-60mph(100kph) test?
