Citroen Picasso 2.0 HDI W reg Tapping in engine

little.tubs · Post by **little.tubs** » 23 Mar 2010, 13:11

Hi,
Can anyone help please, my Picasso has developed a tapping in the engine, on tick over there is no noise, if you drive very gently there is no noise, but if you drive the car under load there is a tapping from the engine untill you get to approx 3500 revs and then it is as though someone flicks a switch and the noise goes when driving over 3500 revs.
Please can anyone help me.
Regards

Post by **RichardW** » 23 Mar 2010, 14:46

This is a well known 'fault' with the 90BHP HDi engine - the fault is worn injectors, which leads them to not giving exactly the right spray pattern on the pre-injection phase, leading to an audible knock. The reason it cuts off suddenly (at 3200 rpm IIRC) is that this is the point that the ECU switches off the pre-injection. AFAIK it doesn't really cause any problems other than the noise, so if you can live with the noise, I'd just ignore it (unless it gets much worse

). New set of injectors is ££££ which may colour your thinking

little.tubs · Post by **little.tubs** » 23 Mar 2010, 16:18

Thanks for the info Richard W, would an ijnector cleaner help in any way IE Redex or so.
Regards
Rich

little.tubs · Post by **little.tubs** » 28 Mar 2010, 21:13

Hi,
Me again, does anybody know if injector cleaner will help with my tapping problem.
Regards
Rich

Old-Guy · Post by **Old-Guy** » 28 Mar 2010, 22:14

As RichardW diagnoses "worn injectors", the problem can't be cured by injector cleaner. That said, injector cleaner won't hurt - do make sure you use a reputable brand and follow the instructions. Too high a concentration may damage the fuel system, too dilute and it won't work properly.

You may find that changing to a quality fuel like Shell will improve matters. Unlike cheap 'supermarket' diesel, a quality brand diesel will keep the fuel system cleaner, burn better with less knock and repay the slightly higher cost with improved consumption.

dieselnutjob · Post by **dieselnutjob** » 29 Mar 2010, 12:03

there is a pin that runs through the injector from the solenoid on the top to the nozzle at the bottom. once high pressure diesel from the nozzle starts to leak past the pin into the solenoid it upsets the balance of the injector so that once the injector has opened, it doesn't close again quickly enough
the consequence is too much diesel during the preinjection phase causing a pinking noise (it basically is pinking but on diesel)
as previously said the ECU stop preinjection at 3200rpm and so the problem goes away
at low power and revs the ECU keeps fuel rail pressure low and so you also don't get the problem
the solution is new injectors. however you probably only actually need one injector
the trick is figuring out which one
some injection specialists can do a spill test which might tell them which one
I did it once by trial and error
I bought one new injector
tried it in cylinder one
no change
so now I put the old injector from 1 into 2
no change
now I put the old injector from 2 into 3
noise goes away
conclusion: the injector in my hand from 3 is the bad one
Also you can sometimes get new injectors much cheaper from injection specialists in France
Don't buy reconditioned ones. I did once and had a bad experience.
The reconditioners can only get replacement nozzles but the problem is the pin and not the nozzle, so half of the recon ones are rubbish in my experience
another option is used ones from crashed cars
there is a Bosch part number on the top of the injector and that's the one that has to match

Post by **DHallworth** » 29 Mar 2010, 12:28

Could this also cause a Xantia HDi to smoke badly?

David.

dieselnutjob · Post by **dieselnutjob** » 29 Mar 2010, 13:10

no

normally smoke is due to lack of air supply which typically points to a boost or EGR problem

little.tubs · Post by **little.tubs** » 30 Mar 2010, 22:00

Thanks everyone for all your help.
Regards
Rich

little.tubs · Post by **little.tubs** » 08 Apr 2010, 20:23

Hi everyone,
Sorry to be a pest again, but i am thinking of getting some new injectors for my picasso, is there anyway i can tell if they are a Bosch or Siemens without taking them out, also is there any difference between 90bhp and 110bhp injectors.
Regards
Rich

wheeler · Post by **wheeler** » 08 Apr 2010, 21:26

It should be on the top of the injector. Besides i've never seen a 2.0HDi picasso with the siemens injection system. They are all bosch.

little.tubs · Post by **little.tubs** » 08 Apr 2010, 23:44

Thank you for the info Wheeler, i have chance of a set of injectors off a 110bhp picassothat has done 40,000 miles but mine is a 90bhp, do you know if they are all the same, or do i need a specific one for mine.
Regards
Rich