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Cylinder Deactivation
113571

L12_048
Figure 231 Cylinder Deactivation
The image shows the right bank cylinder heads from above and the collapsible hydraulic tappets controlled by each OCV solenoid valve . Below shows the entry oil channels and in delivery to the booster pump .
1 Cylinder Deactivation Oil Supply 3 Cylinder Deactivation Oil Channel
113572


Cylinder Deactivation Oil Flow
The white cylinders are Booster Oil Supply (OCV 1-4) - this intrigues me.


Collapsible Tappets
113577
113578
113579


Figure 233 Collapsible Tappets
The collapsible tappets get their normal oil flow for lubrication and their correct operation from the oil channel in red (6) . The lower part of the tappet contains the collapse mechanism . When the channel in blue (5) fills with oil, the collapse mechanism becomes active and the tappet (upper part) collapses .
There are grooves and 3 openings (two on one side and one on the other side) along the external side surface of the tappets that can be disabled. Oil fills groove 2, inserting itself in opening 1 to lubricate the upper part of the tappet, guaranteeing its proper operation . When ECM1 decides to deactivate the cylinders, it sends oil through the OCV solenoid valves into the blue channel (5) . The oil fills groove 4 and from there it goes into openings 3 to activate the mechanism that will make the tappets collapse .

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113583



Tappet Internal

The real tappet is in the upper part (light edge) . It sits on a base that is the deactivation mechanism (green edge) . The mechanism consists of two small pistons (1) that fall onto a lateral housing made along the internal surface of the tappet’s exterior shell . The two pistons support the entire upper tappet .
When ECM1 activates the cylinder deactivation strategy, the chamber between the pistons and the external shell body fills with oil. Oil pressure pushes the pistons, compressing the spring located in the space in between them . When the pistons pull back, they leave the support housing and consequently cannot offer support to the tappet . The result is the tappet collapses downwards; the pistons start moving when the relative pressure is about 0 .8 bar and they are completely at the bottom of their track when the pressure is 1 .2 bar .


113585


The picture above shows the oil flow that the pump sends to the oil channels, making the intake valve tappets collapse. The OCV1 and OCV4 solenoid valves open up the “path” towards the channels feeding the intake valves . OCV2 and OCV3 feed the exhaust valves .
 

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113586


Oil Control Valve Oil Flow to Exhaust Valve Tappets


113588



Oil Control Valve Operation

The OCV solenoid valves have openings along the stalk’s lateral surface . The P openings receive supply channel oil from the booster pump . When the OCVs are not order to, the oil enters from the P openings and goes back out the T openings to return via the head and engine block channels in the sump . When the OCVs are ordered to by ECM1, the cylinder inside the OCV moves to the right, so the oil entering from the hydraulic tappet’s A openings to enter into C openings, where the deactivation cycle will be enabled .
 

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There are two reasons why I do not think the problem is a design flaw.

1) it does not happen to 100% of the 2017 - 2019 QV engines in the US. Yesterday, we were discussing about 1%, others said that it could be higher but, we are talking issues with 1% - 3% of the engines. It does not happen with 2017-2019 QV engines in Europe, or specifically, in the UK. 2) The issue has happened in engines that have been just walnut blasted. It is not possible to see carbon build issues in engines with just few miles.

I may be wrong but, it is not a design problem.

I agree on the quality of the oils and gasolines in the US as well as the ECUs maps not being either updated or working correctly as potential root causes. That may explain why the problem is in the US only, perhaps why the problem is in some parts of the US, or only 97% of the engines or whatever.

Interesting and educative all that stuff presented about the cylinders deactivation technology. But here, I am with @Emozine in regards to what Ing. Pivetti and his Team state. I think this approach is now practically an industrial standard approach so, more probably, not a root cause.
 

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There are two reasons why I do not think the problem is a design flaw.

1) it does not happen to 100% of the 2017 - 2019 QV engines in the US. Yesterday, we were discussing about 1%, others said that it could be higher but, we are talking issues with 1% - 3% of the engines. It does not happen with 2017-2019 QV engines in Europe, or specifically, in the UK. 2) The issue has happened in engines that have been just walnut blasted. It is not possible to see carbon build issues in engines with just few miles.

I may be wrong but, it is not a design problem.

I agree on the quality of the oils and gasolines in the US as well as the ECUs maps not being either updated or working correctly as potential root causes. That may explain why the problem is in the US only, perhaps why the problem is in some parts of the US, or only 97% of the engines or whatever.

Interesting and educative all that stuff presented about the cylinders deactivation technology. But here, I am with @Emozine in regards to what Ing. Pivetti and his Team state. I think this approach is now practically an industrial standard approach so, more probably, not a root cause.
Just for the record, I am not saying it is or is not. I am presenting this info for discussion which is working. ;) I find the theory interesting and I also find it interesting that Squadra Tuning has eliminated this function in the tune.

I also think it is fuel and oil quality. 91 Octane I feel is not enough and the quality varies like crazy. I would not touch Mopar oil whether it is penzzoil/Shell product.

My thinking is low quality Fuel and Oil combo.

Here is a run I logged with my 2.0L on Chevron 91 from a busy station. Fairly optimal conditions but the car still retarded

In the graph below I drew the red line of how it should have been. But because of bad fuel the ignition is retarded.



113590



Outside temp was about 62˚F. 430 Ft above sea level, 60% humidity

See bottom line. This was roughly what time I did the run.

I will add 100 octane today. Do some more runs.

Date

(PST)
Temp

(F)
Dew
Point
(F)
Relative
Humidity
(%)
Wind
Direction
Wind
Speed
(MPH)
Visibility

(miles)
Weather
Clouds
Station
Pressure
(inches)
Sea Level
Pressure
(mb)
Altimeter
Setting
(inches)
1 Hour
Precip
(inches)
3 Hour
Precip
(inches)
6 Hour
Precip
(inches)
24 Hour
Precip
(inches)
6 Hr
Max
(F)
6 Hr
Min
(F)
24 Hr
Max
(F)
24 Hr
Min
(F)
18 Feb 8:53 am​
60​
22​
23​
3​
10.00​
CLR​
29.94​
1025.9​
30.30​
18 Feb 7:53 am​
54​
23​
30​
N​
3​
10.00​
CLR​
29.92​
1025.3​
30.28​
18 Feb 6:53 am​
49​
24​
37​
NE​
6​
10.00​
CLR​
29.88​
1023.9​
30.24​
18 Feb 5:53 am​
47​
29​
49​
N​
CALM​
10.00​
CLR​
29.86​
1023.1​
30.22​
18 Feb 4:53 am​
47​
36​
65​
N​
CALM​
10.00​
CLR​
29.83​
1022.1​
30.19​
18 Feb 3:53 am​
49​
40​
71​
ENE​
3​
10.00​
CLR​
29.81​
1021.5​
30.17​
52​
46​
18 Feb 2:53 am​
48​
40​
73​
N​
CALM​
10.00​
CLR​
29.80​
1021.3​
30.16​
18 Feb 1:53 am​
51​
41​
68​
ENE​
3​
10.00​
CLR​
29.79​
1020.8​
30.15​
18 Feb 12:53 am​
50​
43​
77​
ENE​
7​
10.00​
CLR​
29.77​
1020.2​
30.13​
17 Feb 11:53 pm​
50​
43​
77​
NE​
5​
9.00​
CLR​
29.75​
1019.7​
30.11​
63​
48​
17 Feb 10:53 pm​
51​
42​
71​
N​
CALM​
10.00​
CLR​
29.74​
1019.3​
30.10​
17 Feb 9:53 pm​
52​
42​
69​
N​
CALM​
10.00​
CLR​
29.74​
1018.8​
30.09​
59​
52​
17 Feb 8:53 pm​
53​
41​
63​
ESE​
3​
10.00​
CLR​
29.72​
1018.3​
30.07​
17 Feb 7:53 pm​
54​
42​
64​
SSE​
5​
10.00​
CLR​
29.71​
1017.8​
30.06​
17 Feb 6:53 pm​
56​
40​
55​
N​
CALM​
10.00​
CLR​
29.67​
1016.6​
30.02​
17 Feb 5:53 pm​
57​
41​
55​
3​
10.00​
CLR​
29.66​
1016.3​
30.01​
17 Feb 4:53 pm​
58​
45​
62​
5​
10.00​
CLR​
29.64​
1015.5​
29.99​
17 Feb 3:53 pm​
59​
48​
67​
6​
9.00​
CLR​
29.63​
1015.1​
29.98​
63​
58​
17 Feb 2:53 pm​
59​
47​
64​
W​
8​
10.00​
CLR​
29.62​
1014.9​
29.97​
17 Feb 1:53 pm​
60​
46​
60​
W​
9​
10.00​
CLR​
29.61​
1014.5​
29.96​
 

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Just for the record, I am not saying it is or is not. I am presenting this info for discussion which is working. ;) I find the theory interesting and I also find it interesting that Squadra Tuning has eliminated this function in the tune.

I also think it is fuel and oil quality. 91 Octane I feel is not enough and the quality varies like crazy. I would not touch Mopar oil whether it is penzzoil/Shell product.

My thinking is low quality Fuel and Oil combo.

Here is a run I logged with my 2.0L on Chevron 91 from a busy station. Fairly optimal conditions but the car still retarded

In the graph below I drew the red line of how it should have been. But because of bad fuel the ignition is retarded.



View attachment 113590


Outside temp was about 62˚F. 430 Ft above sea level, 60% humidity

See bottom line. This was roughly what time I did the run.

I will add 100 octane today. Do some more runs.

Date

(PST)
Temp

(F)
Dew
Point
(F)
Relative
Humidity
(%)
Wind
Direction
Wind
Speed
(MPH)
Visibility

(miles)
WeatherCloudsStation
Pressure
(inches)
Sea Level
Pressure
(mb)
Altimeter
Setting
(inches)
1 Hour
Precip
(inches)
3 Hour
Precip
(inches)
6 Hour
Precip
(inches)
24 Hour
Precip
(inches)
6 Hr
Max
(F)
6 Hr
Min
(F)
24 Hr
Max
(F)
24 Hr
Min
(F)
18 Feb 8:53 am​
60​
22​
23​
3​
10.00​
CLR​
29.94​
1025.9​
30.30​
18 Feb 7:53 am​
54​
23​
30​
N​
3​
10.00​
CLR​
29.92​
1025.3​
30.28​
18 Feb 6:53 am​
49​
24​
37​
NE​
6​
10.00​
CLR​
29.88​
1023.9​
30.24​
18 Feb 5:53 am​
47​
29​
49​
N​
CALM​
10.00​
CLR​
29.86​
1023.1​
30.22​
18 Feb 4:53 am​
47​
36​
65​
N​
CALM​
10.00​
CLR​
29.83​
1022.1​
30.19​
18 Feb 3:53 am​
49​
40​
71​
ENE​
3​
10.00​
CLR​
29.81​
1021.5​
30.17​
52​
46​
18 Feb 2:53 am​
48​
40​
73​
N​
CALM​
10.00​
CLR​
29.80​
1021.3​
30.16​
18 Feb 1:53 am​
51​
41​
68​
ENE​
3​
10.00​
CLR​
29.79​
1020.8​
30.15​
18 Feb 12:53 am​
50​
43​
77​
ENE​
7​
10.00​
CLR​
29.77​
1020.2​
30.13​
17 Feb 11:53 pm​
50​
43​
77​
NE​
5​
9.00​
CLR​
29.75​
1019.7​
30.11​
63​
48​
17 Feb 10:53 pm​
51​
42​
71​
N​
CALM​
10.00​
CLR​
29.74​
1019.3​
30.10​
17 Feb 9:53 pm​
52​
42​
69​
N​
CALM​
10.00​
CLR​
29.74​
1018.8​
30.09​
59​
52​
17 Feb 8:53 pm​
53​
41​
63​
ESE​
3​
10.00​
CLR​
29.72​
1018.3​
30.07​
17 Feb 7:53 pm​
54​
42​
64​
SSE​
5​
10.00​
CLR​
29.71​
1017.8​
30.06​
17 Feb 6:53 pm​
56​
40​
55​
N​
CALM​
10.00​
CLR​
29.67​
1016.6​
30.02​
17 Feb 5:53 pm​
57​
41​
55​
3​
10.00​
CLR​
29.66​
1016.3​
30.01​
17 Feb 4:53 pm​
58​
45​
62​
5​
10.00​
CLR​
29.64​
1015.5​
29.99​
17 Feb 3:53 pm​
59​
48​
67​
6​
9.00​
CLR​
29.63​
1015.1​
29.98​
63​
58​
17 Feb 2:53 pm​
59​
47​
64​
W​
8​
10.00​
CLR​
29.62​
1014.9​
29.97​
17 Feb 1:53 pm​
60​
46​
60​
W​
9​
10.00​
CLR​
29.61​
1014.5​
29.96​
Understood. I use Shell 93 octanes and I still have random CELs in rough cold start (misfiring cyl 1, 2 and 3 is the OBD2 error read). It would be very interesting to know if there is any QV engine in the US running the Squadra Tuning with eliminated cylinder deactivation presenting any issue with carbon build or supposed misfiring error codes.
 

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Understood. I use Shell 93 octanes and I still have random CELs in rough cold start (misfiring cyl 1, 2 and 3 is the OBD2 error read). It would be very interesting to know if there is any QV engine in the US running the Squadra Tuning with eliminated cylinder deactivation presenting any issue with carbon build or supposed misfiring error codes.
About 6-10 off the top of my head. I have 2 I know well. I will get in touch, his is an 18' owned from new. Had squadra tune for about 5 months. I can log his car asap as we planned on it anyway.
 

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Well if they say so, heh.


Fun timing on the carbon buildup haha interesting part, about the PCV.
Believe it or not, in early July when I brought the car in for the 2Yr Service, I told them that I still had some random CELs in rough cold starts (misfires on cyl 1, 2 and 3 were the OBD2 errors reads) happening sometimes. They "communicated" with the Alfa engineers and the Alfa engineers, whatever that means, recommended to spray in 2 cans of Mopar Carbon Chamber Cleaner, one per each intake. They did that, using the small ports in each intake and the 2 cans were passed through. So far, so good. No CELs. It is only 20 days since then so, let's see.
 

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More Info that we know and may not, from a friend in FCA and very in-tune with these cars: "The V6s have a much worse reputation here (US), at least the earlier ones ... it is essentially a non-issue in EMEA in comparison ... but additionally not every V6 that was replaced here in the US needed to be either (it was usually a matter of lack of parts), so it wasn't necessarily catastrophic engine failure in every case." This we basically know but it's good info.

"FCA US LLC and FCA Italy SpA had (still largely have) poor communication between each other ... it could also be a matter of certain software that is acting glitchy as software for various modules can vary by region. Also we must keep in mind EMEA also got the E6D dual injection before we did and those are obviously 'everybody's favorite' of the Quadrifoglio V6s. Otherwise engine failure data would be locked away from the public, something I do not have access to." One thing I have mentioned was software.

Main culprit in theory, is Fuel Quality. Some direct injection engines seem fine, some not so, it points in theory to something like fuel quality. Most port injection do well, a few (very few) have not. Oil quality and maybe spec are very important for carbon build up on direct injection. Software is also a concern.

Nuggets of info...

I will dig deeper when I have time.
 

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Discussion Starter · #110 ·
Thank you so much for diving into this. It really helps to have this feedback!

Sounds like a good news for the DI+PI engines. I’ll just let some time go by, and when I’m ready to go back to the QV, I’ll grab a 2020+ 😅

In the meantime, I guess any car between 2017-2019 just has to accept the consequence of bad internal relationships at FCA and ride the warranty while it’s still there. And hoping that before then, a better understanding of the US-specific issue will allow owners to enjoy their cars on the long term.
 

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Squadra tuning for Europe is written for octane 98. So if you drive Squadra tuning with octane 91-93 i can imagine why you are getting misfires. Don't know if Squadra has done an adjustment to the mapping for USA due to low octane levels.
 

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Squadra tuning for Europe is written for octane 98. So if you drive Squadra tuning with octane 91-93 i can imagine why you are getting misfires. Don't know if Squadra has done an adjustment to the mapping for USA due to low octane levels.
Maybe we should just all switch to E-85.

Sorry if there is no E-85 near you
 

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Squadra tuning for Europe is written for octane 98. So if you drive Squadra tuning with octane 91-93 i can imagine why you are getting misfires. Don't know if Squadra has done an adjustment to the mapping for USA due to low octane levels.
Aren’t the Octane rating systems different?

113654
 

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You are correct and this being a car forum I assumed everyone knew that Euro octane ratings were not the same as US. European gas is not 98 octane by US standards.
I knew they were different, lived in Europe for 7 years. I was just being polite by phrasing it as a question 😉
 

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The few issues in the QV engines in the US are with no Squadra tunning, mainly. I tend to agree that root cause may be: gasoline octane and/or quality, oils specs and/or quality and ECUs updates and/or performance. I am running with Shell V-Power NiTRO+ 93 octanes and am testing different gas stations around the city. I am positive that design flaw is not an issue at all (it happens only in few QVs in the US out of the whole world) and based on what has been reported many times in this and other threads, coils, spark plugs, fuel pumps, injectors are not root causes nor both carbon cleaning walnut blasts and changing engines are solutions.
 

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Squadra tuning for Europe is written for octane 98. So if you drive Squadra tuning with octane 91-93 i can imagine why you are getting misfires. Don't know if Squadra has done an adjustment to the mapping for USA due to low octane levels.
You can run 91 octane on the Squadra tune. Preferred 93+ octane. The ECU will adjust for the lower octane.
 
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