Low fuel pressure and gearbox

[John C Green]

Hi,
So, took my C5 Aircross (2019) to be serviced before vacation, they changed the gearbox oil, engine oil and filters, including fuel filter, and in the process they bled the fuel line because, apparently, it had air in it.
The car was delivered, everything OK. Some 15km later, a cascade of errors dumped on my dashboard, drove to shop (I was nearby) and noticed that shifting to/from reverse was clunky.
Among the several errors, two were related to low fuel pressure and gearbox malfunction.
As we started to smell diesel, opening the bonnet revealed fuel all over the compartment, spraying from one of the injector lines. Apparently, after having bled the line, it wasn't well fastened back, but even after being tightened still leaked. So, the problem seems to have been identified, but this long introduction is to ask you why would that result in such a cascade of seemingly unrelated errors (including low tire pressure) and why would the gearbox become clunky as a result of low fuel pressure on one of the injectors?
Could the diesel spray all over the engine compartment create problems with the cabling/sockets, that being the reason for so many errors?

I am not a mechanic nor is English my primary language, so please bare with me. Many thanks.

[GiveMeABreak]

I can only suggest that diesel has gotten into sensitive electronic areas (ECU's Harness plugs / connectors) that have affected other systems.

[John C Green]

I can only suggest that diesel has gotten into sensitive electronic areas (ECU's Harness plugs / connectors) that have affected other systems.

Yeah, everything's going to be cleaned up and hopefully will solve it.
Came from the garage, one of the tubes connecting to the injector (might be a name for these, I don't know what else to call it) is cracked and leaks when temperature rises. The crack can barely be seen on the naked eye. Seems rather weak material compared to some older engines. Matter of fact, I'm left with the feeling this 1.5 bhdi engine is poorly built (and designed, considering the timing chain problem they have).

[GiveMeABreak]

I doubt this is the injector supply pipe as those are under high pressure, so you'd be getting diesel spraying everywhere - but may be the diesel return fuel pipes.

[John C Green]

I doubt this is the injector supply pipe as those are under high pressure, so you'd be getting diesel spraying everywhere - but may be the diesel return fuel pipes.

Not my engine, just for illustration:


It actually is, GiveMeABreak, I've seen it spraying. It cracked near the end where the cone tip is held in place by the nut. The pipe marked by the red arrow on this example, I didn't snap a photo of mine this morning when the mechanic called me to go and have a look at the culprit.

When this happened, the engine cover was soaked in diesel, there was diesel everywhere in the engine compartment, quite like you said: diesel spraying everywhere. It even dripped to the ground!

Now, why the cascade of errors... maybe like you said, fuel messing up connectors. I hope so, because I can't afford more expensive repairs...
Never had problems with Citroens (or any other french car I've owned) but this C5.... sweet fancy moses, can't wait to get rid of it!

[GiveMeABreak]

Crikey! Serious stuff then - makes me wonder whether they removed the fuel supply pipes when doing whatever it was last time and never tightened them back up correctly....

[John C Green]

Crikey! Serious stuff then - makes me wonder whether they removed the fuel supply pipes when doing whatever it was last time and never tightened them back up correctly....

They did remove them. After swapping the diesel filter, they bled the system because it had air in it. Then they tightened them back. Hard to say if the one pipe broke when they fastened it. Possibly.

[GiveMeABreak]

Well I can tell you that if the fuel supply pipes are removed they are officially to be replaced and not re-used! This is according to their own documentation. The reason being is that when the pipes are tightened and torqued they 'form' for a good seal in that they're slightly malleable. When you later remove them they will have been distorted when last tightened and therefore will never seal properly again. Was this a dealer? If so, I'd be complaining, or ask them for the evidence that they were replaced last time.....

[RichardW]

Engine faults interrupt the data to other ECUs and cause a blizzard of faults. Once the low fuel pressure is fixed the other faults should clear.

[John C Green]

Well I can tell you that if the fuel supply pipes are removed they are officially to be replaced and not re-used! This is according to their own documentation. The reason being is that when the pipes are tightened and torqued they 'form' for a good seal in that they're slightly malleable. When you later remove them they will have been distorted when last tightened and therefore will never seal properly again. Was this a dealer? If so, I'd be complaining, or ask them for the evidence that they were replaced last time.....

Is that documentation somewhere to be found publicly, that you know of? I'd like to have a copy, because I'd like to show it. They were so clear stating they released them and tightened back, either they don't know it's a one time only use, or are betting I don't know better (which I didn't, until now). The car isn't at a dealer.

[John C Green]

Engine faults interrupt the data to other ECUs and cause a blizzard of faults. Once the low fuel pressure is fixed the other faults should clear.

Thanks RichardW. I'll be finding out probably later today...

[GiveMeABreak]

Well I can tell you that if the fuel supply pipes are removed they are officially to be replaced and not re-used! This is according to their own documentation. The reason being is that when the pipes are tightened and torqued they 'form' for a good seal in that they're slightly malleable. When you later remove them they will have been distorted when last tightened and therefore will never seal properly again. Was this a dealer? If so, I'd be complaining, or ask them for the evidence that they were replaced last time.....

Is that documentation somewhere to be found publicly, that you know of? I'd like to have a copy, because I'd like to show it. They were so clear stating they released them and tightened back, either they don't know it's a one time only use, or are betting I don't know better (which I didn't, until now). The car isn't at a dealer.

If it was done at a dealer they would of followed procedure and changed the fuel pipes as that is what is required. With non-dealership / non-franchised garages it's hit and miss as you don't know what training, if any, they have had on the systems. The information is held on dealership systems and via technical training - which is why you pay more because of this , so not publicly available unless your specific garage pays for access. But to be honest it should be common knowledge and proper mechanics should know this. It's well-documented on may forums for the same reason the pipes deform once tightened and may not seal correctly once removed and re-used. With a few thousand PSI going through, you don't want to take any chances there - so if it was me I'd be getting them to cough up and sort out the damage and do it properly. This is negligence in my opinion and you'd have grounds for a claim.

[John C Green]

This is negligence in my opinion and you'd have grounds for a claim.

Well, I guess you're right. These are mechanics in their 60's, having dealt with all sorts of cars but not necessarily up-to-date on modern vehicles and their peculiarities. And certainly not on any internet forums or paying access to proprietary knowledge databases. It's also a mistake on my part. After warranty I left the dealership because maintenance was expensive and this garage is just at the corner, I can leave the car and walk back home, and they're always friendly and available, whereas the dealership doesn't have room for kindness or problem solving outside regular working hours if the client finds himself in a pickle (from my experience, but YMMV).

These fuel pipes are the original ones, which had already been reused after my engine needed repair (that timing belt fault these engines are known for), so this was the second time they were re-fitted. I was sort of lucky for having driven around for a bit more than a year without (detectable) issues. Long story short, the garage owner is a decent person and will not charge me for this repair, and after this I guess I'm going back to the dealership for maintenance, until I get rid of this car, which I will.

Many thanks, GiveMeABreak!

[GiveMeABreak]

No problem. That's the issue I'm afraid, 'old skool' mechs are fine with traditional engines and basic maintenance, but modern HDi engines and complex electronic systems require specific training and I think that's true with all manufacturers.

[John C Green]

No problem. That's the issue I'm afraid, 'old skool' mechs are fine with traditional engines and basic maintenance, but modern HDi engines and complex electronic systems require specific training and I think that's true with all manufacturers.

True. I've owned only Renault and Citroen. Never had any problems. I had two previous HDi cars (both were C4 Grand Picassos) and never a problem. This one, the 1.5, was a big disappointment and blow on the wallet. If it wasn't for that, I'd probably be happy and confident on the car. Now I'm not. I think PSA cut corners somewhere when designing and building this engine.

And now, to wrap this up, I'm thinking of going back to petrol (or hybrid) because even though I'm a fan of diesel (near 1000km on a tank... bliss), maintenance is hell. Adblue, adblue problems, particle filter problems, sensor problems... by comparison I remember petrol being so simple... though more expensive at the pump.