Technical It started with a big ol' clonk...

[tjr]

Background:
barchetta -95 w 100kkm on the odometer, it's fairly new to me (my daughters).

Concerning the drive train I've only done some minor stuff; straightened out a kink on the fuel vapour hose (between the charcoal canister and the manifold), changed the thermostat, (and installed a new heat shield). Before changing the thermostat the warm idle was hunting and the engine would be close to stalling, so I was checking spark plugs, coils, icv, and all looked decent. Since then I have found a couple of places where a previous owner and/or mechanic has missed torquing down bolts/nuts (power steering fluid container and lid over fuel pump ass.) and a number of missing bolts and nuts (eg power steering fluid container, driver door handle, fuse compartment). The cam belt and water pump was recently changed by a small shop for a previous owner (according to the service booklet).

Yesterday, it started with a clonk:
My daughter started driving after a stop and there was a large clonk at around 50kph, they could not see anything having fallen off and the car performed ok (and there were no warning lights). After driving through a roundabout they were speeding up to enter the freeway, but when revving up over 2krpm there was a new rattling noise. When letting the rpm drop the rattle quit.

Today:
I tested the b today; it started beautifully, but I also got the rattle at 2krpm when driving. At first I only thought it was a vibration sound so I tore out the newly installed heat shield (did nothing). When only revving the engine (without gear and without driving) the rattle tends to start at higher rpm and sometimes there is no rattle. In one instance I heard the engine being affected by the rattle (not every time), it would not fire as "cleanly". The rattle will quit with rpm dropping and may quit when revving more. Without pressing the gas pedal any further the rpm will fairly slowly continue to rise from 3,2krpm to 4krpm. The rattle will appears "every" time when driving in gear and at just above 2krpm.

A previous owner/mechanic has installed some Alfa Romeo/Lancia parts on the b, including the oil stick(!), I hope it is showing the correct interval (at least no warning light).... Wondering if the variator might not have enough of a oil pressure and the dip stick showing half way, I topped off the oil. This did nothing.

Clueless and pleading for ideas:
Do you have any experience with this type of issue on a b? Any ideas where to start looking? At the moment I believe it is a mechanical problem and not a rusted through heat shield type of deal.

Thanks,
T

 

[tjr]

Without pressing the gas pedal any further the rpm will fairly slowly continue to rise from 3,2krpm to 4krpm.

Just learnt that this describes the effect of the variator(!), thanks to @s130

Thanks to @Nodnolmick and his variator thread I was able to zone in on the variator. By copying his disconnecting the electrical lead, it seems the >2krpm rattle is gone (only one short test drive so far). If it stays this way, it is a huge relief!

Still unanswered:
What caused the big clonk (and what damage did it do)?
Is it the solenoid itself, the lead(s), sensor(s), and/or the ECU, that is at fault?

 

[tjr]

Update:
After a longer drive the hack seems to work to work also for my daughters b

If understanding the Service Manual, 10 - Engine, pages 13, 30 and 31, correctly; the variator is INTENDED to be in ON-position at 1700-4700rpm, this corresponds roughly to when the chatter can be heard in the b.

The ECU activates the variator based on values from the air flow meter and rpm sensor. The ECU activates the Solenoid relay (8), which activates the Phase transformer electro-magnet (1) which pushes down on the Valve opposing spring (3) and lets oil through to the variator moving and forcing the Piston (4) to rotate, the rotation is transmitted to the Pinion (5) and finally the crankshaft.

Supposedly it is possible to activate the timing variator solenoid page 19 with a F / L Tester. Need to look if MultiEcuScan has this option.

Just now I'm leaning towards clogged oil channel(s) and/or a faulty Solenoid relay. I wonder if the latter would light up the dash and/or throw a code? Also wondering where the Solenoid relay (8) can be found (and part number)?

 

[tjr]

Need to look if MultiEcuScan has this option.

Answered yes by @s130, thanks!

 

[tjr]

Just now I'm leaning towards clogged oil channel(s) and/or a faulty Solenoid relay. I wonder if the latter would light up the dash and/or throw a code? Also wondering where the Solenoid relay (8) can be found (and part number)?

Still don't know the Solenoid relay (Sr) part number, but I think I found it in the Service Manual 55 - Electrical system p. 28, under a different name "Relay for phase transformer" (2).

Can anyone translate the Solenoid relay information 30-86-85-87 (from Service Manual 10 - Engine Fuel System p 31)?
30 and 86 both connect to + 30, 85 to 11/B and 87 to the "Phase transformer" (Pt).



Current plan:
1 via MultiEcuScan (MES) test the function of the Pt (ignition on and engine off). I wonder if I'm to listen after a double click. Both the Sr and phase transformer/timing variator solenoid (tvs) should produce them or if MES somehow confirms the function(?)
1.1 if click both Sr and Pt should be ok - go to step 2
1.2 if no click - test Sr and Pt resistance and then look upstream (ECU - air flow meter - rpm sensor), find part(!), replace, and test for function in 2 without noise/rattle

2 try tvs activation with MES when idling
2.1 if ok - the idle should become rough (perhaps the MES will show the camshaft angle change?) and noise/rattle should be induced - go to step 3
2.2 if ok, but no noise/rattle repeat 2 until noise/rattle appears
2.3 if no rough idle go to 1.2

3 run some Wynn's Hydraulic Valve Lifter Treatment (or similar) and see if it can clean out a possible clogging oil channel.
3.1 if ok - case closed!
3.2 if not ok - leave Pt cable off (and pretend the variator does not exist or possibly somewhere in the faaaar future open up the engine and check for clogging or turn over to competent mechanic)

What did I miss?

 

[Wiltshire Chris]

Page 6 of wiring diagrams calls it part 18

The wiring diagram on the next page of the PDF (labelled as page 5) then shows the relay

Sadly, the scan isn't great quality but I think those terminal numbers match. Don't know if that helps at all?

 

[tjr]

Page 6 of wiring diagrams calls it part 18
View attachment 407036
The wiring diagram on the next page of the PDF (labelled as page 5) then shows the relay
View attachment 407037
Sadly, the scan isn't great quality but I think those terminal numbers match. Don't know if that helps at all?

Thanks @Wiltshire Chris, good to have confirmation from another source. I’ll check out the wiring diagrams section.
I hope to get to testing on Sunday.

 

[s130]

Well FYI I can NOT find the variator solenoid on the last ePER. I can't find a part number. It is not shown for the Barchetta, Punto HGT or even the Coupe.

If anyone has purchased or know the part number then I can try a reverse search.

 

[tjr]

Page 6 of wiring diagrams calls it part 18
View attachment 407036
The wiring diagram on the next page of the PDF (labelled as page 5) then shows the relay
View attachment 407037
Sadly, the scan isn't great quality but I think those terminal numbers match. Don't know if that helps at all?

@Wiltshire Chris Oddly when I looked up the same wiring diagram (downloaded from here), it would zoom in with crisp quality (well legible)...! Thanks to your find lead 85 (color Z) goes to A Injection system failure warning light and thus should light up the dash if something goes/went wrong?

@s130 It is strange isn't it? Could it be a generic relay?

 

[s130]

@Wiltshire Chris Oddly when I looked up the same wiring diagram (downloaded from here), it would zoom in with crisp quality (well legible)...! Thanks to your find lead 85 (color Z) goes to A Injection system failure warning light and thus should light up the dash if something goes/went wrong?

View attachment 407057
@s130 It is strange isn't it? Could it be a generic relay?

Probably a generic relay as it only has to turn the solenoid on and off. Have not pulled the cover off on our "B" to look but the circuit diagram show just a typical normally / normally close relay.

The big mystery is no listing for the solenoid itself.

 

[Wiltshire Chris]

This is guesswork and I'm unfamiliar with the engine bits but based on your pictures but could it be this:

which takes me to this as an option

FIAT ALFA ROMEO COUPE GT GTV 146 147 156 COLD START VARIATOR VALVE A370 71736025 | eBay

PART: EFEL A370 /71736025. The item may not fit every and all vehicles listed. Our sales team aim to respond as quickly as possible. Most Performance parts are not sold with a warranty. We will always help you to have a 100% positive happy buying experience.

www.ebay.co.uk

and this

https://www.alfaowner.com/threads/variator-solenoid-dissected.475697/

and this might be useful

https://www.alfaowner.com/threads/variator-solenoid-fiy-repair-guide.476153/

 

[Wiltshire Chris]

Caveat. That is for the M2 engine so may not apply
*EDIT* Ignore that caveat, looking at the book for the M1 engine and it's the same part number

 

[s130]

This is guesswork and I'm unfamiliar with the engine bits but based on your pictures but could it be this:
View attachment 407070
which takes me to this as an option

FIAT ALFA ROMEO COUPE GT GTV 146 147 156 COLD START VARIATOR VALVE A370 71736025 | eBay

PART: EFEL A370 /71736025. The item may not fit every and all vehicles listed. Our sales team aim to respond as quickly as possible. Most Performance parts are not sold with a warranty. We will always help you to have a 100% positive happy buying experience.

www.ebay.co.uk

and this

https://www.alfaowner.com/threads/variator-solenoid-dissected.475697/

and this might be useful

https://www.alfaowner.com/threads/variator-solenoid-fiy-repair-guide.476153/

Well it might be?

Probably is.

On the Barchetta/Punto/Coupe this come up under Intake Manifold
On the Lancia Gamma this comes up under Cam Shaft Drive

On the Internet everywhere seems to list is as a Cold Start Valve.

Price is a shocker - from Fiat in 2014 then £432.85 thank you very much!

 

[Wiltshire Chris]

Price is a shocker - from Fiat in 2014 then £432.85 thank you very much!

Yes, I saw that, shocking. Perhaps that's why there's that post on the Alfa Forum about repairing them

 

[tjr]

Probably a generic relay as it only has to turn the solenoid on and off. Have not pulled the cover off on our "B" to look but the circuit diagram show just a typical normally / normally close relay.

The big mystery is no listing for the solenoid itself.

How little I know (https://www.12voltplanet.co.uk/relay-guide.html):
Terminal numbering convention

The terminal numberings found on a relay body are taken from DIN 72552 which is a German automotive industry standard that has been widely adopted and allocates a numeric code to various types of electrical terminals found in vehicles."

If I understand correctly it is also called 4-pin SPST relay or "make & break relay" "The most simple form of relay. The circuit between terminals 30 and 87 is made on energisation of the relay and broken on de-energisation, known as NO (or vice-versa for a NC relay)."

 

[s130]

I've not driven with this disconnected but I gather it makes a small difference at higher RPM moving from better torque low down to more power top end.

At these prices for the both a new variator (yes I know about the cheap repair kit) and the valve it would be tempting to bypass both of them. (weld/fix the variator in the home position and it required knobble the solenoid position)

 

[tjr]

I've not driven with this disconnected but I gather it makes a small difference at higher RPM moving from better torque low down to more power top end.

To be honest, I can't really tell the difference between connected and disconnected...

 

[s130]

To be honest, I can't really tell the difference between connected and disconnected...

Interesting to hear, which sort of supports what I've heard/read elsewhere.

As in life (especially with cars, motors, etc) then there are:

1) Clinical rolling road data etc.

2) Who in real life can really and quantify A vs B (not talking about adding a turbo to a stock engine etc)

3) Even if you could in 2) then does it buy you that much?

Right that said there is the "drivability" profile/satisfaction. This is basically how your car drives and responds to your expectations and experiences with other motors/vehicles of similar "stance".

I suspect (but have no proof) that a lot of this OLD style variable cam timing was probably about getting the power vs emissions balance right, with a little added engine performance flexibility, in balance with a moderate right foot accelerator pedal operation.

So a challenge to those who may wish to personally explore and feedback

Go drive your "B" with VVT enabled and disabled, low throttle, full throttle, low rpm. full rpm, etc. and give us all an honest feedback of with VVT or without VVT (read variator operation)

 

[tjr]

Interesting to hear, which sort of supports what I've heard/read elsewhere.

As in life (especially with cars, motors, etc) then there are:

1) Clinical rolling road data etc.

2) Who in real life can really and quantify A vs B (not talking about adding a turbo to a stock engine etc)

3) Even if you could in 2) then does it buy you that much?

Right that said there is the "drivability" profile/satisfaction. This is basically how your car drives and responds to your expectations and experiences with other motors/vehicles of similar "stance".

I suspect (but have no proof) that a lot of this OLD style variable cam timing was probably about getting the power vs emissions balance right, with a little added engine performance flexibility, in balance with a moderate right foot accelerator pedal operation.

So a challenge to those who may wish to personally explore and feedback

Go drive your "B" with VVT enabled and disabled, low throttle, full throttle, low rpm. full rpm, etc. and give us all an honest feedback of with VVT or without VVT (read variator operation)

In all fairness, I'm not the best person to judge the difference of variator 1 or 0 (not the sharpest tool in the toolbox). This is what https://www.austincc.edu/wkibbe/vvt.htm state concerning VVT:

"Without Variable Valve Timing technology, engineers used to choose the best compromise timing. For example, a van may adopt less overlapping for the benefits of low speed output. A racing engine may adopt considerable overlapping for high speed power. An ordinary sedan may adopt valve timing optimise for mid-rev so that both the low speed drivability and high speed output will not be sacrificed too much. No matter which one, the result is just optimised for a particular speed.

With Variable Valve Timing, power and torque can be optimised across a wide rpm band. The most noticeable results are:

• The engine can rev higher, thus raises peak power. For example, Nissan's 2-litre Neo VVL engine output 25% more peak power than its non-VVT version.
• Low-speed torque increases, thus improves drivability. For example, Fiat Barchetta's 1.8 VVT engine provides 90% peak torque between 2,000 and 6,000 rpm.

Moreover, all these benefits come without any drawback."

The drawback part is open for discussion considering the quality/maintenance issues with the barchetta VVT.

 

[tjr]

Yes, I saw that, shocking. Perhaps that's why there's that post on the Alfa Forum about repairing them

Thanks for finding the part number. With it I did some further searching and supposedly (right or wrong), the solenoid is also sold as part no 5896137. It is available on eBay.it for €126, which is still steep, but more palatable.

Edit, the solenoid also seems to go by A370 and can be had used for €17...