citroen c3 problems.....injectors etc

[adamyates]

hi i've had a few problems with the citroen for a while now,a thread i posted before is here http://www.frenchcarforum.co.uk/forum/v ... highlight= to which jamesQB was very helpfull but i shal recap

it started off with problems starting and losing a bit of power on the parkways when accelerating but would then suddenly kick in again but then it quickly changed into it wouldnt start full stop,i got it to a local diagnostic garage and they read the codes and told me it was the fuel pump so i got it home and ordered one off an online scrappy to which they sent a bosch pump when i requested a delphi one. so i sent it back and ordered one from somewhere else which they fobbed me off by not sending it within a month,so i dememded my money back and after 6 weeks and a solicitors letter i finally got my money back off those which ment i had to get it from somewhere else,in the end i rang all the delphi service centers and got a recon one at a good price

i fitted the new pump (and changed the belts etc while i was at it) and i started the car up and it started pretty much first time(as a novice/amatuer machanic i was sooooo happy) so my wife drove the car 100 odd miles to her parents for a visit but when she came home she went to start the car and lo and behold same problem the rac got her home by using quick start,it drove fine once running so she used it for a week or so using quick start every time,very peeved off with the garage that said it was the fuel pump

i then did some more reaserch on here and saw about a leak of test so i made up a kit and tested the injectors and found 3 to be quite bad(1 very bad)so got to work on changing those,2 came out very easily and 1 was an absolute nightmare but i got there in the end,i took them to a local delphi center and got 3 exchange ones,got home and fitted them-i re used the old high pressure pipes because after all the expense i've had so far i dont wanna pay another £150

then this weekend my lexia 3 arrived so i set about programming them in which i managed to do quite easily-checked and doulble checked that the codes stayed in,i read somewhere on here that cylinder 1 is near the gear box and 4 at the timing belt end...is this correct?

so now i have a new pump and 3 new injecters fitted and all progrmmed in but it's still not good,it still doesnt start straight away-takes about 5-10 seconds of cranking when cold but starts ok in mid afternoon and theres still a lot of white smoke under revs

any idea what the problem is cos im all out of plans now and im due to sell the car to my sister as soon as its fixed so i dont wanna sell her a bag of bolts????????

thanks in advance
adam yates

[JamesQB]

Hi again Adam. I can help a bit. Cylinder 1 being at gearbox end is my understanding and how I found my injectors were coded. When I fitted a 2nd-hand injector, I carried out a leak-off test straight away, which showed the 'new' injector to have very low leak-off. It was only a month or so later that it, and 2 others, developed high leak-off for some reason, which exhibited itself as hard to start again (sometimes half a minute of cranking), sounding rough and being low on power output. White smoke at certain revs was also apparent, but mainly when car was sat in neutral idling after first starting, and moreso when revving to about 2K and holding.

I wouldn't have suspected the HP pump myself as I've read it's not known to fail, whereas these injectors are plagued by failure. I would now carry out a leak-off test, to ensure the recon injectors are good. Should have a 12-month warranty.

Re: injector pipes, I've re-used them 3 or 4 times now, and they're fine. No perceptible leaks whatsoever. I do them up to 20Nm on re-fit using a crow's foot adapter.

Someone on here (was it you, or in one of the topics you started?) found the plastic turbo outlet pipe was leaking at the o-ring seal joint to the turbo body and used silicon between the mating faces to stop loss of power and turbo kicking in late in the rev range. Might be worth a bash.

Since you have a Lexia, get the live data up and start the car when it's cold. See what pressure it's showing on the HP side during cranking. A minimum pressure is required before it'll fire, and high leak off is one thing that reduces the pressure causing it to be hard to start. I suppose if the recon HP pump was itself slow to build pressure, it might be the trouble also? I'll have to see if I can find what pressure is required during cranking, it was 260 or something like that. Maybe someone else knows?

Turbo's spinning freely by hand is it? Other than that, I can't think of anything else to check. Would a leak in the turbo outlet pipes or intercooler cause hard starting in an HDi does anyone know? Incidentally, any fault codes reported in Lexia?

[boristhespie]

I know ot sounds obvious but can you explain leakoff.

Also how do you get live injector data in lexia.

[JamesQB]

I haven't used the Lexia in ages, and didn't use it much to begin with, so I'm afraid I personally can't help with that as I can't remember, but no doubt someone else knows.

With leak-off, it's diesel returning to the tank from the injectors. Basically, the injector nozzle opens via indirect means: a control chamber at the top of the needle assembly which fills with diesel under HP rail pressure, while more HP diesel sits around the needle lower portion, creating an equal pressure above and below, so the needle is neither pushed up or down. Slight downward force is maintained to keep the needle fully closed by a weak spring.

When the solenoid in the top of the body actuates, it pulls a valve up in the control chamber allowing the diesel in the control chamber to move to the leak-off outlet where the leak-off, or return, pipes are connected to the body of the injector. This loss of pressure at the top of needle assembly allows the higher pressure diesel acting on the lower portion of the needle to push the needle up, thereby opening the injector.

It is this control chamber valve wearing and allowing too much diesel to flow past that's the trouble. So you have excessive amounts of diesel flowing to the leak-off pipe at the times when it should be sealed.

This diesel travelling from control chamber to leak-off pipe also acts as a lubricant on those moving parts. I've got the common rail injector which was replaced here, so I'll take it apart and post pics. Might be interesting for some.