2008 1.6hdi grand c4 picasso

[Theogster]

Hi all, first post, hoping someone might have some French car specific knowledge on this...

Last November my C4GP threw a wobbly, started throwing up multiple and seemingly random dashboard warning, ranging from parking brake to anti pollution system, and gearbox faults, managed to limp it home and the next day it wouldn't even start,

I'd had a couple of those warning previously along with starting issues, but that was just the battery failing, it had a new battery and those issues completely went away, so my first thought was the new battery had failed in some way, but it tested out OK, and even trying a different battery made no difference...

Symptoms...

Car will crank, and run for 2 or 3 "beats" as tho there's nothing wrong, then it just dies, feels like it's either only getting the fuel that's primed & in the pipes and dies once that's used, or it's starting, then it a case of "computer says no"....

Car sat like that for around 5 months, I'm on a very strict set budget so I'd been tinkering with it myself rather than getting someone to look at it... took the battery out, checked the fuses and tried to inspect the main ecu & fuse compartment for corrosion etc, but never found anything that looked obviously "bad"..

But, bare in mind, I'm an idiot using Google.... I can be fairly handy, but I know nothing and have zero experience....

I had wanted to try and get under the car to check around the exhaust, and maybe get some of the sensors off to test for throughput and give them a clean, but unfortunately poor health and being fat makes that difficult......

About 2 months ago I got a couple of hundred £ together and tried a few auto electricians on Facebook marketplace, out of the 5 I contacted 4 just said they wouldn't look at at it, because they assume it'll be the usual French car unsolvable rabbit hole...

One came out, and started stripping stuff back and testing it, and his first comment was that it wasn't getting fuel pressure... then before he did anything else we tried starting it again, and it fired up, running sweet as a nut for the first time in 6 months...

He had no idea why, and was completely honest about that, but the car was 100%

I ran the car all that day trying make sure whatever had been the cause was worked through, even putting it in manual gear mode & running it up & down a local bypass at 3k revs to help clear the dpf in case that was the issue,

The car had no problems re starting and was running g perfectly...

Until I went to it the next morning, and it was dead again.... that was 2 months ago....

I've been in & out of hospital for the last 6 weeks so haven't been able really do anything with it, but yesterday at the hottest part of the day, (30c ambient temp, 39c in the car) I tried it randomly, & the damn thing fired up again, like nothing had happened...

I'd bought some redex dpf cleaner, and whilst I couldn't take it on the road due it currently being sorn & uninsured, I put the cleaner in the tank and ran it at 3k revs for 15 mins, let it idle for 5 mins, then did another 15 mins at 3k revs, it kicked out a good bit of smoke & soot, & I drove it up & down the back street (unadopted Road with a barrier on the inly entrance) and again, it seemed to run 100%

Went out to it again this morning, and no joy, turns over, starts and runs for a couple of beats, then just cuts out :/

I would genuinly hate to scrap it, best car I've ever had for mpg and comfort, but I'm properly at my wits end with it, anybone got any ideas ?

[mickthemaverick]

Hi and welcome to the FCF

There is a thread with a similar problem which may be worth you reading. Mainly it seems a possible leak in the fuel system allowing air in which stops the fuel getting through. If that is the case then your engine should at least fire up on Easystart and then die due to fuel starvation:

viewtopic.php?t=73126

[RichardW]

Unfortunately, without a scan tool you will get no where on a modern car - but it needs to be a decent one that can read live data. At least it has the ability to run, so there is nothing seriously wrong. Where are you, there might be someone within striking distance that has a Diagbox clone that could interrogate it.

[Theogster]

Thanks for the replies, it's been on a couple of "proper" scanners, one by my regular mechanic who I have used for years & does the MOT & servicing, and the auto electrician, it did give a few codes, but none related to the issue..

I can't explain further because I don't know enough about it.. so I kinda have to take their word for it...

We did a quick check for leaks etc, and everything seems fine and it's had half a tank for about 8 months, doesn't seem to be losing anything, and when it does decide to run, it's perfect, which is the thing that's really boggling my noggin...




I'm hoping someone will see this and just be...

Oh, that's such an such, a specific sensor or selanoid or something daft....

It really does seem to be a French car specific thing, the auto electrician's that wouldn't even entertain looking at it all said basically the same thing, it needs someone very familiar with this age of citroen/pug that already knows what it's gonna be....

If that makes sense lol.....


EDIT= regarding the fuel thread, mine starts, runs for 2 or 3 beats then cuts out, but where as in that thread it would only crank but not fire after the first try, mine repeats exactly the same no matter how many times I try, crank, start, runs for 2 or 3 beats then cuts, like somethings cutting in and telling it to shut down....

Then I'll go to it and it'll randomly start and run perfect for a bit..... then back to square one the next day

[mickthemaverick]

The fact that it starts for a few revs every time suggests to me that the problem is going to be down to the immobiliser cutting in. However that is very much a dark art and hopefully someone with better knowledge than me will be along soon. Good luck.

[RichardW]

Needs more than codes - live data will be king here. But also the ability to interpret what it is telling you!