C5 2.2 HDI Low Power and Sluggish

KevMayer · Post by **KevMayer** » 07 Mar 2010, 15:03

Does anyone know how the 3rd piston works on a Hdi pump ?

cachaciero · Post by **cachaciero** » 07 Mar 2010, 18:52

KevMayer wrote:Does anyone know how the 3rd piston works on a Hdi pump ?

Solenoid operated deactivated when fuel temp exceeds 106 deg C according to Bosch Training notes, so I guess if the connector is out that means less than ideal pressure / flow BUT I would have thought that would give you lower performance at the higher end but overall better fuel economy ( but I could be wrong

Cachaciero

KevMayer · Post by **KevMayer** » 08 Mar 2010, 10:53

Today I drove to work with the connector pulled off the '3rd piston disable' connection. This would leave the 3rd piston in service all the time.

I didn't notice any change to the performance. This means that either the 3rd piston is faulty and always out of service, or, the fault is elsewhere.

I think I'll remove the 3rd piston solenoid to see if there's anything obviously wrong. I'll also take the pressure regulator off the pump to see if that looks ok.

Is it possible to strip down these pumps any further?

EDIT:

A friend of mine has a 2.2 Hdi estate on a 52 plate. He tells me that his C5 has so much torque that it would 'pull you up the side of a house!'

My C5 with the same engine is no where near that kind of performance (although it's hard to quantify the difference, my friend is just so pleased with his car's performance and that's without a tuning box or remap).

There hasto be something fundamentally wrong with my engine.

cachaciero · Post by **cachaciero** » 08 Mar 2010, 11:14

KevMayer wrote:Today I drove to work with the connector pulled off the '3rd piston disable' connection. This would leave the 3rd piston in service all the time.

.

Kev

Don't think that that's right, read what I said, my understanding is that the solenoid is deactivated to disable third pump that equates to connector out.

Your friends comments about the 2.2 agree with mine, yes there does appear to be something fundamentaly wrong with yours I suspect the air side rather than fuel side although having said that how's your throttle? early C5's have a long throttle cable in my case mine was badly stretched and a long way from max even when the pedal was on the floor, made a big difference adjusting it.

cachaciero

KevMayer · Post by **KevMayer** » 08 Mar 2010, 18:54

Do you have any figures for the boost pressures of the 2.2 HDi?

I can connect a boost gauge and check out the high pressure air system.

cachaciero · Post by **cachaciero** » 08 Mar 2010, 19:48

KevMayer wrote:Do you have any figures for the boost pressures of the 2.2 HDi?

I can connect a boost gauge and check out the high pressure air system.

Not at the mo, will need to plug the Lexia in and get some values from that.

However if you disconnect the vac pipe from the Turbo electrovalve and then go and drive you should soon get the dreaded polution warning followed by the engine going into limp mode that will at least prove that you are getting enough pressure of the turbo under some situations to trigger a turbo overboost. (Electrically Disconnecting the EV isn't the same the ECU will detect that it is not there and likely do something that could confuse the result).

Really as I said at the beginning you would be well advised to get the ECU read on a Lexia that will tell you all that is wrong.

cachaciero

KevMayer · Post by **KevMayer** » 08 Mar 2010, 20:55

Thanks once again cachaciero.

I'll do as you suggest and disconnect the vacuum pipe to the turbo actuator and see if I get the overboost (Anti pollution ESP/ASR faulty alarm).

Found this data for the 2.2 Hdi in my C5 (mk1 02 plate) in the 'Citroen Service Documentation Backup'

Engine code DW12 TED4
Engine legislation type 4HX
Component number Specific to the vehicle
Number of cylinders 4
Bore x stroke (mm) 85 x 96
Capacity (cc) 2179
Compression ratio 18/1
Max. power (E.E.C) 98 kW
Max. power (HP DIN) 136 hp
Max. power speed 4000 rpm
Max. torque (E.E.C.) 31,7 m.daN
Max. torque speed 2000 rpm
Turbocharger Variable geometry
Air/air heat exchanger Yes
Boost pressure (2000 rpm) 1,1 bar
Boost pressure (3000 rpm) 1,2 bar
Injection system HDI (*)
Make BOSCH
Type EDC 15C2
Smoke opacity (m - 1) Specific to the vehicle

So, 1.2 bar at 2000 rpm and 1.3 bar at 3000 rpm. I assume this is the no load pressure.

cachaciero · Post by **cachaciero** » 08 Mar 2010, 22:29

1.2 bar at 2000 sounds about what I vaguely remember last time I looked.

Cachaciero

TopDonkey · Post by **TopDonkey** » 08 Mar 2010, 22:56

the 3rd piston deactivation solenoid comes in and out as and when its needed to save wasting power as the high pressure pump consumes about 3.5kw of power, it deactivates when the engine doesnt need a pressure above 1000 bar in the fuel rail (about 80% certain of that value), once the pressure requested exceeds 1000 bar, the 3rd piston is reactivated by de-energising the solenoid and the pump runs at full power again, so unplugging the connector just wastes power and heats the fuel excessively by keeping the 3rd piston engaged all the time

cachaciero · Post by **cachaciero** » 09 Mar 2010, 16:01

TopDonkey wrote:the 3rd piston deactivation solenoid comes in and out as and when its needed to save wasting power as the high pressure pump consumes about 3.5kw of power, it deactivates when the engine doesnt need a pressure above 1000 bar in the fuel rail (about 80% certain of that value), once the pressure requested exceeds 1000 bar, the 3rd piston is reactivated by de-energising the solenoid and the pump runs at full power again, so unplugging the connector just wastes power and heats the fuel excessively by keeping the 3rd piston engaged all the time

Interesting and sounds quite plausible what's your reference because it aint what the Citroen / Bosh training manual says.
Wonder what the fuel temp gets to once it's compressed to a 1000Bar.

For Kevs problem running with the connector out was just a way of making sure the 3rd piston is activated to see if it makes any difference to his problem, although again from the same reference with the connector out i.e solenoid de-energised the 3rd piston is DEACTIVATED NOT ACTIVATED so I'm not sure that it would prove anything.

Don't get me wrong I'm not saying that your explanation is incorrect, the Citroen / Bosch Training Manual I have is fundamentally incorrect in at least one other key area that I know about but I would like to know the source of your information just so I can come to a conclusion as to which is the correct explanation.

cachaciero

TopDonkey · Post by **TopDonkey** » 09 Mar 2010, 16:07

I did a training course on it with my previous company about 7 or 8 years ago now and seem to remember all the fuel system stuff for some odd reason!, i am relying on my memory though, which is likely to be less reliable than your bosch notes !!, next time i do a drive with planet connected, i will try the third piston plugged and unplugged and watch the fuel rail pressure, as that will tell us which way round it works

Also, i've been watching the 3rd piston deactivation solenoid in peugeot planet and you can watch it switching on and off as you rev/drive, and the fuel temperature goes up loads because another thing that planet monitors in live data is the fuel temperature.

KevMayer · Post by **KevMayer** » 09 Mar 2010, 17:04

I've just been for a run with the turbo actuator vacuum pipe disconnected.

On a straight with a reasonable amount of acceleration I get the Anti Pollution ESP/ASR alarm which must have been caused by a turbo overpressure. This must mean that my turbo and air pipework are working ok.

On the 3rd piston issue, the 'Citroen Service Document Backup' information explains how the 3rd piston is deactivated.

When the solenoid is energised it pushes a plunger down which holds open the suction valve of the 3rd cylinder. This means pressure cannot build up in the 3rd cylinder. So, 'energised' must correspond with 'deactivated'.

My thoughts are that if the suction valve of this 3rd piston were faulty/stuck open then the 3rd cylinder may not be working. I'd not reach max pressure or max performance. The only way to find out is a Lexia session I suppose.

I think I'll try a Bosch specialist rather than a main dealer. The Citroen dealers local to me are only good at selling cars.

cachaciero · Post by **cachaciero** » 12 Mar 2010, 18:38

TopDonkey wrote:I did a training course on it with my previous company about 7 or 8 years ago now and seem to remember all the fuel system stuff for some odd reason!, i am relying on my memory though, which is likely to be less reliable than your bosch notes !!, next time i do a drive with planet connected, i will try the third piston plugged and unplugged and watch the fuel rail pressure, as that will tell us which way round it works

Also, i've been watching the 3rd piston deactivation solenoid in peugeot planet and you can watch it switching on and off as you rev/drive, and the fuel temperature goes up loads because another thing that planet monitors in live data is the fuel temperature.

Well your comments plus Kevs subsequent comments have convinced me.....
the Bosch / Citroen training manual is WRONG AGAIN!!!!!
God help any mechanic that doesn't have any other source of info

cachaciero

cachaciero · Post by **cachaciero** » 19 Mar 2010, 21:25

Hi Kev

And.........?

Cachaciero

KevMayer · Post by **KevMayer** » 21 Mar 2010, 09:31

Hello mate,

I got myself a new airflow meter off ebay for £39.

The element in the old MAF had gone green and furry at the edges so must have been suffering. The only thing I can think of is that I could have sucked up some water during the recent snow/slush while travelling down the M1.

The new MAF isn't a genuine bosch, but, the C5 has come to life. It is a lot better than it has been for some time, although I've not been far in it for a while because I've resorted to using my Activa for everyday and I can't stop smiling.

I'll be back in the C5 soon because my Activa only does 27 mpg, that's acceptable considering how much fun it is to drive.