Injector leak-off rates, P0191 code, clutch bearing, oh my!

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RustyUK
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Injector leak-off rates, P0191 code, clutch bearing, oh my!

Post by RustyUK »

Does anyone know what the nominal leak off rate should be for injectors fitted to a 2.2HDi?

My MK1 C5 (156k miles) has started giving intermittent P0191 codes, registering low fuel pressure and throwing it into limp home mode - very annoying! It's only ever done this at idling speeds.

Done a leak off test today (using a £3 glass bottle spice rack, very neat and tidy!) and determined after exactly five minutes at idle, injectors 1 - 4 leaked 38, 30, 34 and 35ml respectively. Injector 1 seems a candidate, I fear 3 and 4 too, but I don't know what the expected rates should be. Also an oddity: I wasn't expecting the fuel return pipe to be under any sort of positive pressure, so I didn't clamp it off at first. Imagine my surprise when it starts gushing diesel everywhere upon starting! Is this normal? I had expected it to simply run back to the tank. Anyway...

Of more show-stopping importance, it seems I've also now lost my clutch release bearing which appears to be a pull type. Slave cylinder operates, but can't disengage clutch! The bearing sounds somewhat 'crunchy' operating it manually having removed the cylinder. So now I'm at that point, wondering whether it's worth spending the time and money restoring a working car, or just saying goodbye to it (fortunately my crazy back-up plan is keeping me on the road meanwhile, I also run a Matiz for just this sort of occasion!)

If I really have to change more than one injector (assuming I can even get it out...) then it's game over. Which would be an enormous shame, given the love I've shown this car. If I press on and fix the clutch (cheapest kit inc. solid flywheel I've seen is at GSF for £366), can anyone share any advice re: removing the gearbox? It doesn't look too complex, assuming the engine can remain firmly in situ, but I've only ever removed a Sierra gearbox so really no idea what to expect from a large FWD engine like this! Some accounts suggest the engine needs moving around to free it, which is not really something I'm equipped to do.
Peter.N.
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by Peter.N. »

Your leak offs are not wildely different, I don't think you necessaraly have a problem there - but you do with the clutch.

Peter
RustyUK
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by RustyUK »

Perhaps they're ok,I was expecting to see a more dramatic difference I have to say. But that leaves an unanswered question then, if leaky injectors aren't causing the occasional idle fuel pressure drop, what is? The pressure sensor was replaced 5 years ago, I suppose it's possible the regulator is a candidate (which I think just bolts on to the back of the HP pump?) Not sure what else I can do to diagnose the P0191 fault, which would be useful before committing to replacing the clutch.
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by KevMayer »

Do you know why the fuel rail pressure sensor was changed 5 years ago?
Was the new sensor a genuine Citroen unit? If not, it may have failed again.
Your leak off test doesn't suggest a big problem with your injectors. If the problem is at tickover then do you have a tuning box fitted. This backs off the voltage from your fuel sensor to the ECU. It may be sending a low voltage at tickover.
Other than that, If the injectors are ok a low fuel rail pressure could be due to a leak, a faulty pressure sensor or a faulty regulator on the HP pump.
I'm interested in this problem because I have the same engine.
Good luck.
Cheers, Kev

02 plate C5 2.2 Hdi Exclusive SE (now 170k miles 03/21).

Used to have:- Xantia 1.9 TurboD SX. 1996 Blue & 1998 Silver Activa. + 1992 BX TZD Turbo.
RustyUK
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by RustyUK »

Not sure what the original code was, I had that diagnosed and replaced at a Citroen independent in Bradford. No idea of the brand sensor fitted. To be honest I was sort of hoping one injector would be the obvious culprit, as then I could make a firm decision about whether to press ahead and fix the clutch, or just scrap it! As it stands, I'm not sure how much work in involved yet getting the gearbox off (working on a driveway outdoors in winter, ugh) so not sure whether to risk it and hope the fuel pressure issue is 'cheap' future fix, or give in now.

At the moment I can't find anything else in the locality to replace it with (2.0 C5 or smaller C4, for example) - virtually no private sellers at all, only rip-off dealers :(
flying clutchman
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by flying clutchman »

Can't help you with injector info but I can tell you the clutch is a difficult job. If on a scale of difficulty 1-20 I would rate a sierra as a 3, The diesel C5 would be a 15
Peter.N.
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by Peter.N. »

Ah but the Sierra has the engine the right way round.
flying clutchman
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by flying clutchman »

Interesting response peter,but the 5 vehicles you list all have the engine the 'wrong' way round! Personally I prefer fwd cars and they don't NEED to be more awkward. In the last 10 years PSA group have decided to make their previously straightforward clutch changes really difficult. The 1.6Hdi models are ridiculously bad to do---and don't need to be.
Peter.N.
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Posts: 11563
Joined: 02 Apr 2005, 16:11
Location: Charmouth,Dorset
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C5 X7 VTR + Satnav Hdi estate Silver
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In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars.
x 1199

Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by Peter.N. »

Fortunately I haven't had to do one yet, I did one on an XM though and that was hard work. I would like to run RWD vehicles but I need a large estate and the only option is I think a Merc E class, its almost impossible to get a manual box, they are not very good on fuel and they go rusty. The C5 does a better job at a fraction of the price.

Peter
flying clutchman
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by flying clutchman »

Xm is about the only citroen I've not done. Should imagine it's a pig. The old CX with the 2.4 or 2.2 engine used to take me best part of 2 days!
Peter.N.
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Posts: 11563
Joined: 02 Apr 2005, 16:11
Location: Charmouth,Dorset
My Cars: Currently:

C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red

In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars.
x 1199

Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by Peter.N. »

I had one of those out too, a 2.5 turbo CX Safari, I did over 150,000 miles in it and had to replace the head gasket about every 15k due to a pourous block, that was an easy job though. I eventually took the engine out and had the block machined - that wasn't, and it didn't make any difference either.

Peter
RustyUK
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by RustyUK »

So other than the obvious extra work involved removing drive shafts and wheel liners, what makes removing a C5 gearbox a 15 on the 1-20 scale, or harder than other similar FWD cars?
flying clutchman
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Re: Injector leak-off rates, P0191 code, clutch bearing, oh

Post by flying clutchman »

depends what you're comparing it with, I supose, but the biggest problem is that the (heavy) gearbox is a very tight fit . The drive shafts are not any particular difficulty.
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