Technical 1.3 Diesel - P0089 and the fuel filter of doom...

[bugsymike]

I always found Darwen Diesels very helpful.
Have you seen this online re diesel injection? http://vu67.ucoz.ru/toplivnaja_sistema_dvigatelja_evro-3.pdf

 

[jackwhoo]

You are being redirected...

Link to genuine Bosch item from decent supplier I have used several times.

 

[Matt Quinn]

You are being redirected...

...Thanks Jack; yes, a Bosch 0928400825 is currently wending it's way here as we speak; ordered it this morning after I got the car started.

 

[jackwhoo]

At one end of the fuel rail is the rail pressure sensor , on the other end is either a blanking plug or dumb pressure relief valve with no electrical connector or an ecu controlled valve a 2nd part of the rail pressure control system.

Which type does yours have?

 

[Matt Quinn]

I always found Darwen Diesels very helpful.
Have you seen this online re diesel injection? http://vu67.ucoz.ru/toplivnaja_sistema_dvigatelja_evro-3.pdf

Thanks for that Mike.... I hadn't seen that; and I'll be sure to save and digest it; actually that is really really useful.

It's interesting that page 11 says:

"Transfer pump supplies fuel from the fuel tank to the
pumping chambers of the high pressure pump.

Fuel metering valve regulates the fuel intake volume
to the pumping chambers of the high pressure pump."

and 15/16

"When solenoid de energized, valve is open
= LOW fuel volume intake to pump.
When solenoid energized, valve is closed
= HIGH fuel volume intake to pump."

Interestingly - this suggests that the 'new' valve I obtained (which didn't work) is operating in the correct phase... whereas the old one (which does 'work') is faulty; i.e. closed when de-energised.

"Energized by ECM via negatively triggered PWM."

PWM being Pulse width Modulation; a common technique for controlling things like motor speed, dimming incandescent lights etc. - Inductive loads. So this is modulated from the fully energised (+12v nominally) down towards 0V or 'earth' as we might usually think of it in the automotive context.

...Again; this does seem to be suggesting (as you say) that the valve is operating on the high-pressure side; curiouser and curiouser!

 

[Matt Quinn]

One one end of the fuel rail is the rail pressure sensor , on the other end is either a dumb pressure relief valve with no electrical connector or an ecu controlled valve a 2nd part of the rail pressure control system.

Which type does yours have?

I have a note here of the rail being Bosch 0445214217 - As far as I recall (the plastics are back in place) it only has the rail pressure sensor; though I will double-check tomorrow when I get a chance.

 

[Bantamsteve]

Hi there ,sounds like a frustrating few days for you. To bring you up to date my end ,I've had a new fuel filter fitted today , it's made no difference to my symptoms (same as yours I'm thinking) so now I need a new plan .

 

[Matt Quinn]

Have you seen this online re diesel injection? http://vu67.ucoz.ru/toplivnaja_sistema_dvigatelja_evro-3.pdf

Just a quick note to the above for the record... Page 21 seems to suggest that high pressure regulation is a "System Variant"... Which in turn implies two possible scenarios as previously discussed. It would be useful to track down the speaker's notes.

 

[Matt Quinn]

Hi there ,sounds like a frustrating few days for you. To bring you up to date my end ,I've had a new fuel filter fitted today , it's made no difference to my symptoms (same as yours I'm thinking) so now I need a new plan .

Hi Steve... If I were you I think I'd be a bit frustrated at the garage mechanics! You wrote previously;

I've changed the rail sensor and regulator but it still the same

- You did this yourself as I recall. Did you use new parts? Is your pump the same model as mine (see pics above for type etc)... I assume from what you wrote it is the type with the 'regulator' on the pump. - The mystery at this stage being whether that regulator sucks or blows!

Changing the fuel filter turns out to be quite an easy job; easier than changing the regulator in my view, and not worth paying a garage to do. But during that initial three weeks in the garage, I'd have expected them to clean out the lift pump; possibly blow through the lines and replace the filter, at an earlier stage. - I'd now be expecting the garage to turn to the sort of leak-back test Mike has suggested.

At the end of the day, you expect a garage to have trained/qualified people and the right equipment. - Random gadgies taking stabs in the dark (as I'm doing here) is what we can do for free ourselves.

Maybe get a more informed opinion from elsewhere and possibly re-check the lines etc... but I suspect the next step is Mike's leak-back suggestion. Out of curiosity... you're getting a code; but does your scanner give you the rail pressures and the 'freeze frame' when the MIL comes on?

 

[Bantamsteve]

Hi matt, I concur with all that you say, frustrating but hay ho it's only a car,worse things happen.yep the leak back test is probably my next avenue, at least I know the tank pump is OK, as is pressure regulator, and pressure sensor,I consider it maintenence on a pre emptive basis that way it doesn't seem as bad as it could be ,after all there probably original parts ,gonna go sometime ,it's a fiat ! The thing is I like the car very much it suits my lifestyle and job ,I just want it to work like you do ,. Keep the faith we will get through this ,together , good luck tomorrow

 

[Matt Quinn]

Pressures seem roughly acceptable, more to the point what were the Error codes you read.

One of the figures you were responding to Mike (way back in mid-December) being...

Name:Engine Coolant Temperature
Value:15°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:2056/min
--------------------------------------------------------------------------------
Name:Air Flow Rate from Mass Air Flow Sensor
Value:24.39g/s
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:45600kPa
--------------------------------------------------------------------------------
Name:Fuel Level Input
Value:40.0%
--------------------------------------------------------------------------------

45600kPa... at 2056rpm?

The new FPR was been fitted last week; unfortunately, I've been ill again and not had a chance to go out and gather data or test anything. However, after the new FPR was fitted and the car started I recorded these figures:

*********************************STREAM Page:3*****************************

Name:Engine Coolant Temperature
Value:23°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:2500/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:54800kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:6*****************************

Name:Engine Coolant Temperature
Value:26°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:2740/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:57800kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:15****************************

Name:Engine Coolant Temperature
Value:48°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:3081/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:59400kPa
--------------------------------------------------------------------------------

...Bear in mind these figures are kPa; that figure at 3000 RPM is just under 600Bar - and back in December the figure at 2000rpm was roughly 450bar. (AFAIK you divide kPa by 100 to give you bar)

Something I haven't been able to find is any kind of chart or spec sheet that gives a list of what I should be expecting. But an awful lot of what I'm reading (which, as I've found out can be 'all over the place in terms of being misleading) seem to be suggesting that these pressures should be much much higher.

...What am I missing here? And can anyone direct me to a definitive chart or list of expected pressures? The scanner in use is a Creader/Launch 529; which was cheap etc. - Is there perhaps an issue with the reader? It seems to be very badly designed and documented; and it wouldn't surprise me if it couldn't resolve/display higher pressures and somehow 'fluffs' them. - But (even bearing in mind the car is simply being revved and isn't under any sort of load) are these pressure figures really acceptable?

 

[bugsymike]

I realise not a linear reading against engine revs, but a quick search for operating pressure for Bosch CP3 injector pump and got this.

"All three pumping chambers are tied together in one circuit internal to the pump and provide high pressure fuel between 300bar (4351psi) and 1600bar (23,206psi) through a steel line to the fuel rail. The pump is driven at 1:1 engine speed and is not responsible for injection timing."

On my Scudo a quick flooring of the throttle got as much as 2000 Bar, this on an old pump.
I have used several different Launch code readers over the years and no particular doubts re accuracy of your Creader/Launch 529.

 

[Matt Quinn]

I realise not a linear reading against engine revs, but a quick search for operating pressure for Bosch CP3 injector pump and got this.

"All three pumping chambers are tied together in one circuit internal to the pump and provide high pressure fuel between 300bar (4351psi) and 1600bar (23,206psi) through a steel line to the fuel rail. The pump is driven at 1:1 engine speed and is not responsible for injection timing."

On my Scudo a quick flooring of the throttle got as much as 2000 Bar, this on an old pump.
I have used several different Launch code readers over the years and no particular doubts re accuracy of your Creader/Launch 529.

Thanks Mike... yeah; I'm seeing a lot of that all over the place, which is what is causing me to question the figures I'm seeing. I do think I need to test more and do more research though before reaching (or jumping to) any more conclusions. What is out there (by way of information) seems to be pretty inconsistent and incoherent...

For example - it emerges that the correct FPR for that pump is indeed 'normally closed' - i.e. only opens when energised; which is the opposite of what Tony Kitchen's 'Powerpoint presentation' says; to be fair to Tony; the 'slides' are out of context without the supporting notes - and while the slides can be found on many internet sites; the supporting notes can't!

The 51900kPa (519 bar) figure at 3192rpm is offload, not floored, and held there for a few seconds.

On my Scudo a quick flooring of the throttle got as much as 2000 Bar, this on an old pump.

I don't have a recording of it (so may be kidding myself on) but I think a very brief accidental 'blip' of the throttle produced a very brief 1200 bar (120000 kPa)... but this was something seen in my peripheral vision. Some figures pulled from a truncated recording - which I was unable to print - seem to hint that part of the control algorithm adjusts pressure according to load as well as demand; i.e. blip the throttle and the pressure blips as the revs rise; being reigned back in if there is no corresponding load. - That is entirely speculation though.

Just for the record; my gripes with the Launch Creader... in case anyone else is tempted.

For clarity; I used to actually teach User Interface (UI) design as part of a multimedia course at HNC/D level back in the days when I lectured part time at Stow College in Glasgow. I also had to learn programming as part of my own studies. It's not particularly unusual for us to have to actually have to build and program certain types of controllers - for motion control rigs etc. - So I'm not someone who routinely struggles to find their way around a computer-based device.

My concerns about the device arise because what I'm seeing here are literally 'schoolboy errors' in design and implementation; that and a fundamental lack of care, attention and competence on the part of those who wrote the firmware/software. And it's that, in turn, that causes me to question its accuracy.

...The UI on this device is a shambles; to the extent that if a kid turned this into me at the end of first year for their HN project; they'd be getting it back for remediation. A simple example; you shouldn't have to back in and out of related pages to change a simple function. - 'Record' shouldn't be buried as a page in the set-up menu; and there should be a clear way (with user-feedback) of stopping and starting recordings/test sessions.

When you select specific items from the datastream to monitor; it should be possible to come out of that page, review your data and re-enter the datastream monitoring page with your pre-selected items still intact. - It isn't; and it's a timewasting/frustrating faff to have to re-select them.

- Why limit the items you're viewing/recording at all? - The device, not unexpectedly, has (very) limited memory; which you'll be using up. Besides which, it's necessary to get the items you're interested in on the same page in order to monitor them simultaneously. Even the order in which items are presented isn't particularly logical; nobody has thought this thing through.

From the instruction book:

"Q: How to record the live data?
A: While viewing the live data, press [OK] to record the diagnostic record for
later printing. The saved records are stored in “Print” in the Job menu.

Q: What to do if I want to print the saved record?
A: The saved records are stored in “Print” in the Job menu. To print the record,
user needs to visit www.x431.com/CR529 to download and install the
update tool on the computer since the print manager is integrated in the
update tool. Refer to Chapter 5.5 Print for details."

None of those things work reliably... You can never be sure the unit is actually recording a session (there is no indicator); and if it runs out of memory (which it does quite easily) it simply truncates the recording - leaving it unavailable for printing. You 'might' be able to review it manually on the screen of the device. The software/app (bearing in mind it's from 2019) for the device 'Creader Series Updater' is among the worst I've seen. It often (60% of the time) fails or refuses to connect to the reader at all; and even when it does, will frequently tell you that the serial number doesn't exist! - You cannot even chose where to save downloaded .txt files from the unit.

It is, quite literally, something I'd have expected from a kid straight out of school in the early 2000s. Having said all that... it's a very cheap scanner; and will be useful enough to keep in the boot of a car for emergencies. In that sense 'OK' - but I don't entirely trust it.

 

[Matt Quinn]

So... Snow/cold having stopped play again last week; an update.

I deliberately avoided any attempt to start the car during the last cold snap... given the circumstances which kicked off this chain of events. So; on Tuesday just past the car was started again with the intention of gathering some more pressure figures; bearing in mind what Mike has said;

On my Scudo a quick flooring of the throttle got as much as 2000 Bar, this on an old pump.

...and everything I've read about the pressures involved with this system; once the car was warm I decided to 'floor the throttle briefly'. This caused the check engine light to come back on, and the usual P0089. The car would not then rev past 3,000rpm. Reviewing the codes showed a P0087 (Fuel Rail/System Pressure - Too Low) waiting in the wings as 'pending'.

Wednesday, (having reviewed this data, and noted it as best I could) I decided to try starting the car again. It was clearly restricted (limp mode of some sort?) to 2800rpm. Clearing the codes didn't immediately clear this restriction on the first start (car turned fully of and back on again); but on the second it was gone and the car revved normally. - it was too wet outside to do the leak back test; a suitable kit having been acquired.

However, it was then possible to very briefly rev to about 5000rpm with no more than about 800kPa appearing on the diagnostic tool. - Nowhere close to 2000bar or even the 1200-1600 that I've seen suggested might be expected. Unfortunately this was one of those occasions where the tool failed/refused record!

And so to today; the earliest window of opportunity I've had due to the weather...

The leak-back test, previously suggested was run... and the raw results are shown in the picture below:

For clarity... the problem as I see it is rail pressure collapsing; the theory under investigation being excessive leak-back from the injectors. Disregarding the imbalance for a moment, one or two things are, I think, of note.

1) The kit in use is one of the cheap £20 types obtained off eBay. The numbers on the 'graduates' are entirely arbitrary and basically meaningless; i.e you might expect 10ml per division from looking at it, but that's really not what's indicated! Each 'division' - is actually about 5.6ml! So - if you use one of these kits you will also need a proper measuring device, a notepad and a pen!

2) The general consensus I've been able to glean suggests a figure of 25ml/minute (for each injector) is 'acceptable' as a limit; therefore I'm working on the basis that for leak-back to be responsible for low pressure on the rail (i.e. pressure collapse) it would need to be far in excess of 100ml/min (collectively, for all four injectors) to be at the heart of this problem.

...I happen to have in my lock-up, an old photographic (i.e. proper chemical) measure. So; I've been able to measure the volumes fairly accurately. From left to right (nominally 1-4) these are:

(1) 30ml
(2) 35ml
(3) 50ml
(4) 45ml

Over the 279 seconds of the test... this equates to leak-back rates of;

(1) 5.4ml/min
(2) 7.8ml/min
(3) 10.8ml/min
(4) 9.6ml/min

Collectively (between all four injectors) that's 34.4ml/min - surely this should be well within what the system can cope with; without the pressure collapsing?

Bear in mind the chain of events here... It seems that waxed fuel 'killed' a previously serviceable lift pump. On reflection it's possible to form the opinion that, during the attempts to start the car, the high pressure pump was also (resultantly) partially 'starved' of fuel/lubricant; and that whatever did reach it done no good! After being partially refuelled with 'winter' mix and a cleaning agent... the car 'ran' again; but not well or reliably.

Fuel pressure figures...

*********************************STREAM Page:1*****************************

Name:Calculated LOAD Value
Value:38.4%
--------------------------------------------------------------------------------
Name:Engine Coolant Temperature
Value:16°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:891/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:30400kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:2*****************************

Name:Calculated LOAD Value
Value:29.4%
--------------------------------------------------------------------------------
Name:Engine Coolant Temperature
Value:36°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:834/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:27600kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:3*****************************

Name:Engine Coolant Temperature
Value:39°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:835/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:28200kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:4*****************************

Name:Engine Coolant Temperature
Value:43°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:2467/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:51800kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:5*****************************

Name:Engine Coolant Temperature
Value:44°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:1357/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:36400kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:6*****************************

Name:Engine Coolant Temperature
Value:56°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:1691/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:36000kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:7*****************************

Name:Engine Coolant Temperature
Value:60°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:1792/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:38000kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:8*****************************

Name:Engine Coolant Temperature
Value:68°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:1466/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:32800kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:9*****************************

Name:Calculated LOAD Value
Value:21.2%
--------------------------------------------------------------------------------
Name:Engine Coolant Temperature
Value:69°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:802/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:26400kPa
--------------------------------------------------------------------------------

*********************************STREAM Page:10****************************

Name:Calculated LOAD Value
Value:11.4%
--------------------------------------------------------------------------------
Name:Engine Coolant Temperature
Value:78°C
--------------------------------------------------------------------------------
Name:Engine RPM
Value:1439/min
--------------------------------------------------------------------------------
Name:Fuel Rail Pressure
Value:32600kPa
--------------------------------------------------------------------------------

This is remember al with a new - Lift pump, Fuel Filter and Fuel regulator.

...As always; any input would be appreciated. I am beginning to form an opinion; but I'd like to hear the thoughts of others on this.

 

[bugsymike]

Just got back from a day with grandchildren etc. Now going to chill with a pint of very dry rough cider, not an everyday habit I assure you, just fancied a change.
However in an ideal World the leak off tests would show one injector way up high compared with the others, so easy to condemn.
Assuming no other influences, and each return pipe is individual and only connected to that bottle and you are happy with your conversion figures, they do appear high, I got this from another site "I used to work at a diesel specialist, we used to run them at idle for 3 minutes, anything over 30ml is excessive back leakage."
I know you could argue they were selling a service, so maybe compare other sites.
I did try to get figures from Bosch website, but nothing straight away so maybe worth you having a look.
I like things to be black and white before condemning the injectors, but may be looking that way.
I have heard of people making up a blank where the feed from the pump goes to the common rail to get a figure without the injectors connected.
However given the Extreme pressures involved probably not recommended.
Is it possible that at the beginning of your troubles some dirt/contamination got as far as the injectors?
Given the cost of reconditioned injectors, I would possibly be tempted to get a set from a scrapyard from a working "alleged" engine if cost effective, alternatively have yours tested and hopefully with you standing by to watch.

 

[Matt Quinn]

Just got back from a day with grandchildren etc. Now going to chill with a pint of very dry rough cider, not an everyday habit I assure you, just fancied a change.
However in an ideal World the leak off tests would show one injector way up high compared with the others, so easy to condemn.
Assuming no other influences, and each return pipe is individual and only connected to that bottle and you are happy with your conversion figures, they do appear high, I got this from another site "I used to work at a diesel specialist, we used to run them at idle for 3 minutes, anything over 30ml is excessive back leakage."
I know you could argue they were selling a service, so maybe compare other sites.
I did try to get figures from Bosch website, but nothing straight away so maybe worth you having a look.
I like things to be black and white before condemning the injectors, but may be looking that way.
I have heard of people making up a blank where the feed from the pump goes to the common rail to get a figure without the injectors connected.
However given the Extreme pressures involved probably not recommended.
Is it possible that at the beginning of your troubles some dirt/contamination got as far as the injectors?
Given the cost of reconditioned injectors, I would possibly be tempted to get a set from a scrapyard from a working "alleged" engine if cost effective, alternatively have yours tested and hopefully with you standing by to watch.

Yeah; I saw that post the other day... and actually what it's implying is approximately 10ml/minute. On the other hand; I have come across several sites saying 25ml per minute.

Injector leak off test (1.6HDi, M59, 92bhp)

Hi all, I just did an injector leak off test on my car. I am not writing a full description as I made a video of the whole procedure. The link is below. The video is for a Peugeot Partner (a badge dif

www.berlingoforum.com

There is a video available from his post: I couldn't re-post it here.

 

[bugsymike]

Something is giving you low pressure, you tried the sensor/regulator side so presumably pump or injectors.
Just it would be nice to have a visible fault , like one leak off through the roof.
Having said that yours does run and often when one leak off reading is really high the engine doesn't even start, so it may be time to have the injectors tested or replaced if a cheap option.
Do you have an injector specialist nearby who can advise what is acceptable given the issues you are experiencing.

 

[Bantamsteve]

Hi everybody I've not got mine sorted yet but I'm booked in next week at a diesel specialist, I can't wait ,he seemed to think ,on what I told him that it could be the high pressure pump , it's booked in for Wednesday ,I'll let you know the outcome ,

 

[Matt Quinn]

Something is giving you low pressure, you tried the sensor/regulator side so presumably pump or injectors.
Just it would be nice to have a visible fault , like one leak off through the roof.
Having said that yours does run and often when one leak off reading is really high the engine doesn't even start, so it may be time to have the injectors tested or replaced if a cheap option.
Do you have an injector specialist nearby who can advise what is acceptable given the issues you are experiencing.

Injectors on this engine appear to be a terrifyingly expensive option... I'm not aware of a local specialist, no.

As has been the case all through this fiasco; the information that is out there is both incoherent and often contradictory.

Currently, I'm trying to trace some sort of credible data on what the leak-back figure ought to be. ...Figures seem to vary widely; and to be honest a solitary figure like '30ml' is meaningless without (a) the time involved and (b) knowledge of the specific vehicle involved. - I found out earlier this evening that 40ml/min is fine for certain Volvo engines for instance! So it looks as if there is actually no 'one size fits all' figure.

Page 32 of the pdf file to be found here:

Bosch Injector Test Plans 29 Web - PDFCOFFEE.COM

S3000 Common Rail Test SystemInjector Designation:- 0 445 110 002 Type Designation:- CR/IPS19/ZEREK10SLT DTEST DAT...

pdfcoffee.com

...Provides test bench data for the Bosch 0 445 110 083 injector which I believe are fitted to the engine. This seems to lend some credence to the 25ml/min figure being touted around (i.e. you can see where it's come from).

 

[Matt Quinn]

I'll let you know the outcome

Thanks Steve, I'm sure that will be useful for anyone who finds themselves in a similar predicament. It would be interesting to know the mode of failure of these things. i.e. one pumping chamber failing; could that lead to an inability to generate pressure at the higher end. And what ballpark the actual pressures ought to be. - It's interesting that at 1500 rpm the test bench is looking for 1350 Bar - or 135000 kPa and with no firing pulse the same at 2000 rpm. - Also noteworthy is that at 1500rpm/1350Bar the maximum back leak can be up to 55 ml/min!

Obviously - it's reasonable to assume that the behaviour on the car will be different... but if those are the physical characteristics of a good injector; thent the system has to be designed to cope with them; surely?

Something is giving you low pressure, you tried the sensor/regulator side so presumably pump or injectors.
Just it would be nice to have a visible fault , like one leak off through the roof.

In all honesty... an injector that was wildly off is the worst possible case. They're expensive, difficult to remove (require extra tools etc) and in any case: there are four of them! The big difficulty is finding some conclusive information that would help make sense of the data gathered so far.