Broke down, now will not start.

[citroenxm]

Unless your Engine Management Light is on, or been on to Record a Fault, then a Lexia wont show much, just previously recorded faults..

My sisters non starter shows NO issues or faults, the only issue I can see is the lack of the Fuel Pressure building up to allow the injectors to trigger.. other then that nothing..

Im following this very closly, and shall try your procedure.. Where exactley was the "EGR" Plug, on the front or back of the engine..?

Cheers

[Stickyfinger]

Hi...

Rear of engine , under the EGR Valve. Check the wires are all ok (if they are broken = No Start....dirty contacts= intermittent.

You need to take off the air trunks and air filter box to get to it. Its a push in fitting with the lift clip so you have to work blind without gloves. I am sure others here know the name of it.

Pollution engine management fault light goes out after this. ( But I think this is a false light caused by the miss-fires)

I will report back the results. Still not happy with it as last night I had about 5-10 "single miss-fires" on a 30 mile run out last night.
These happen at any time, not just when accelerating for example

[oscar]

Hi try removing EGR valve and give it a good squirting of cleaner as looked at one few years ago that wouldn't run/start as get gummed up with crap from engine etc got a 2nd hand one in end it was ok then. Did some weird things but these are the PSA/Fraud engines? theres a post from someone with a C5 1.6 getting rid of as failed MOT for problems

[Stickyfinger]

Hi

I had thought that I may have to remove the EGR system totally but was trying to avoid it as its a little sod to get at.

Trying to make up my mind about FAP filter replacement /or/ removal with re-map before the next MoT as I have the "Risk of P-F-Blockage" light coming on ......an Italian Tune-Up has not worked.

[Stickyfinger]

OK...been to Phil Hunt's at Marnhill

Its about 25 miles away....and this is what happens

Car does fine with full power for about 12 miles, it then starts with the "single miss-fire" every mile or so for about 5 / 6 miles then the miss-fires increase.
The car does this every trip longer than 10 odd miles.
The miss-fire then gets worse until ----All-Stop. (Normally wait 15-20 mins to re-start---- then all Normal again)
NO FAIL CODES Show via Lexia

It did the Above on the trip over this morning.

The drive back....Zip--bugger all...naught....No problems.... no miss-fires at all ! aggggggggggggggggg

[RustyUK]

My feeling's always been if the ECU logs nothing then the problem is likely mechanical in nature and not something under computer control. Eg, if it were a cam or crank sensor, the discrepancy should be logged. If it were low fuel pressure, it should be logged. I'm not sure that there's much else that really happens in within a modern diesel, other than engine speed measurement (crank sensor), air flow measurements (MAF sensor). There may also be a manifold pressure sensor. Fuel is squirted at the correct time calculated by the ECU, the mechanics of the engine (compression, timing) take care of the rest. None of the other fluff has any real bearing on it.

So, could your timing be slipping out? (Not sure how it could 'slip in' again when cold, mind). Might it be loosing compression when warm?

That said, could it perhaps be something like the MAF sensor? It may not be faulty enough to be out of spec, but if it's not recording the correct air flow, perhaps the ECU's injecting too little fuel, causing progressively worse lumpy running? (then again, maybe it should throw an error if the engine's turning fast but it thinks there's too little air flowing).

It's always possible the ECU itself is faulty, perhaps not generating enough power to open the injectors properly.

Then again maybe the clue is in your risk of DPF blockage warning. Could the exhaust not be exiting the cylinders quickly enough, gradually choking it?

[citroenxm]

Injectors wont open if the Fuel Rail pressure is not high enough... On MY CAR issues, the only thing I could see was the fuel pressure wouldnt rise enough.. The Cam and crank were Syncronising..

I have a slight advantage, my Mother has the same engine in a C5, so I connected the lexia up to that and watched the parameters... The Fuel pressure in the rail rose continually when cranking.. to around 240psi then it fired.. I also noticed after stopping the engine the pressure dropped SLOWLY too...

My sisters, stopped rising at 103psi.. and dropped immidieatly.. so firstly Im going to atempt the rail pressure sensor. Otherwise it could be a pump issue. The pressure regulator.. I beleve its on top of the pump and a bit easyer to get at.

[RustyUK]

On my HDI the pressure regulator is on the back of the pump (round thing, probably just a small stepper motor, I let the injection specialist replace it but it looks trivial). The plug sticking up on top is to control the third piston.

When I had low pressure issues for even just a moment, the ECU did notice. In that case I only experienced problems when dropping to idle, which the injection guy diagnosed as a sticky regulator (pump was tested on a rig).

[citroenxm]

Rusty.. was that a 1600 16v hdi you had issues with?

[RustyUK]

2.2 - don't know if there's any difference in pump. I'd imagine the principles and required pressures are the same.

[citroenxm]

Ah the 2.2 pumps are very different to the 1.6 16v pumps..

2.2 pumps are same as 2.0 8v pumps. I know the 2.0 8v engines inside out..

[Stickyfinger]

Thanks guys

Rusty....the misfire is that....a sudden loss then away again, the type that throws you forward and back if accelerating hard
It is not a gradual power loss
It runs real smooth (for a 16tdi ) when not missing.

Its as if the ignition was turned of for one fire, but no warnings, no blips on the rev counter

[RustyUK]

Most odd. Coincidently my other half's 307 has started doing exactly the same thing. Intermittent running-misfire-running again for months then quite quickly turned almost permanent, typically on the morning we were going to drive to London from Doncaster with a horrible lumpy idle. That's a petrol though (1.4 8v) so probably a different cause. No recorded errors either.

I'm half way through doing the head gasket and a quick valve job. While I'm not certain yet what that cause is, we did find the head gasket looked shot to ribbons (it had been suspected to be iffy for months anyway, with a small mount of oil seeping into the coolant). Compression tests always held 13 bar in every cylinder, but it looked like rotten blistered cardboard when we got it off. It needed doing even if it wasn't the cause.

Whether it'll run like new again or still have its misfire remains to be seen (valve seals won't be here this weekend I've just discovered, damn it). Not sure if a wonky HG can cause an intermittent loss of compression, you'd have thought it'd be permanent if it's failed enough to do anything. But given diesels rely on much greater compression to ignite I do wonder if you might be sometimes loosing some somewhere?

[Stickyfinger]

OK the saga continues...

Just swapped the seats......well when doing this I found chafed wires (which will be air bag bells every 3 miles or so )....anyway....ever since

The seats have been out there has been Zero misfires !.....

Just come back from a 300 mile round trip....Zero Misfires....Zero warnings ?? HOW can this be connected ...or is it ......

or is it just "French"

[citroenxm]

Ooooooo how strange.... Earthing prehaps on the same earth point... ???

Least yours goes.. Ours has turned out to be a dicky Fuel Pump... Now Re-Con, or 2nd hand....