Pauls HDI Xantia Exclusive.

[citroenxm]

Ive got more vids etc to post up, but photobucket is pissing around and is sooooo slow..

[KP]

YouTube them then Paul so much easier

[taffy]

you tube is much better

[citroenxm]

Take just as long to upload!

[Eddie Nuff]

yea id say 200k ones could well be at the end of theyre life as i read they should be reconned at 100k.

My HDi is the same as Pauls bar a few months, she has 197k on her and the original injectors are like new and have not been re-conned.

Maybe you could use mine as a base for the Lexia info you need?

[KP]

How big are they Paul as mine upload pretty quick via the mobile app

[citroenxm]

So, here Goes... This is what happens to me...

[citroenxm]

yea id say 200k ones could well be at the end of theyre life as i read they should be reconned at 100k.

My HDi is the same as Pauls bar a few months, she has 197k on her and the original injectors are like new and have not been re-conned.

Maybe you could use mine as a base for the Lexia info you need?

Id like to STRESS: THIS PROBLEM IS NOT AN INJECTOR OR SET OF INJECTOR PROBLEM. THERE IS NO WAY IN HELL THAT THREE SETS OF INJECTORS CAN ALL BE SHAGGED AND CAUSE THE SAME PROBLEM...

What ever is going on .. its ON THE CAR, people with HDis approching 200k all original you have NO WORRIES!!!

Taxi man's Xantia did 283k without this problem...

My problem lies else where... Look at the vids and see what I endure! NOTE: If I drive like a old giffer, then she is perfectly fine!

[KP]

What happens if you crawl past 3k revs upto the red line? Is it fine then if you do it gently, ie little boost?

Does that hdi90 you have run if you put all the bits back on it as that would be perfect to compare side by side up and down the lane

[citroenxm]

Course not threw the car away months ago.. but it did before I broke it up...

I'm not convinced .. three sets no.. four Including my original set knackered?? No. I don't think so..


as for crawling.. look at the vid first gear is fine. It's when I goto second and increase the demand.

I can hold the throttle on full blast 4k revs and it will rev all day. . It's the heavy demand that does it.

[KP]

Exactly what I'm trying to get at. Boost in 1st won't be as high as second as it just doesn't have the time to build and this the fuel delivery rate required isn't as high either.

Yet if you struggle in 2nd+ gears the lack of fuel pressure is causing a safety shutdown to save the engine.

[taffy]

that was horrible to watch!
its odd this cause when i had over boost it would die but not stop it would pick up again( slip road to m4 it would still let me build up speed gently but if i gave it some it would die but then come back to life) but just for the sake of it paul you can do a quick install off a boost gauge easy just to eliminate it...its rather odd i think it could even be related to the throttle potentioner readings perhaps giving wrong values maybe...this is a tricky one but keep guessing and we will get there:) when it stops have u got ur foot to the floor?

[Eddie Nuff]

The point I was trying to make was that the injectors on these are like the engines - they just go on and on . . .

I don't see it as an injector fault, I don't really see it as a fuel fault tbh. The way the engine dies immediately in the video says it's more electronic than fuel. Whether it's a faulty sensor or such giving duff info or a poorly ecu wrongly interpreting good info is beyond my knowledge.

In order to eliminate it from investigations have you thought of having the ecu checked to see if it's faultless?

[citroenxm]

I've got other écus I could chuck in with matching body computers yes I probably could.

I will end up doing so. Trying to do the easier things first.

[RichardW]

Paul

Here's my understanding of what's going on.

The regulator gets a modulated signal from the ECU so it opens to the correct amount. I think a permanent signal = closed, no signal = open. ie it is open when the engine is stopped. There is no return from the fuel rail, so the pump must supply the correct amount of fuel to the rail to match what is being injected , and keep the pressure steady. The ECU monitors the rail pressure, and then sends a modulation signal to the regulator to set the fuel pressure (and hence flow) accordingly. Now, when you make a demand on the fuel system, the ECU reacts by changing the position of the regulator so that the rail pressure matches the reference value. If the pressure is still lower than reference, then it keeps trying to close the regulator until it does come right. However, if the regulator goes essentially closed (ie signal > 97%), or the pressure remains more than 250 bar below the reference, then ECU assumes that there is a leak somewhere and shuts the engine down. I believe this is what is happening to yours. So causes, some of which we can rule out:

Leaking injectors – rule out, you’ve had more than one set in, and leak off is OK, the fuel is not escaping that way
Rail pressure sensor – probably rule out, again you’ve changed it, and the measured pressure is a match for the reference pressure.
Rail pressure sensor supply cable – a possibility, it seems to have supply and earth from ECU – should be 5V on supply, minimal on earth and 0-5V on signal pin. Could be a fault that is giving a high earth resistance and therefore a false reading (although see above….!)
Regulator – still a possibility. You’ve changed the pump (and the reg) but could be a bit of swarf on the end of the reg causing a problem.
Fuel filter – not sure if you have changed? Could be a problem if restricting flow at higher rates. Easy and cheap(ish) to change if not done recently!
Pump – unlikely, as you have replaced, and you have enough pressure to start, which would likely show up a poor pump.
Blockage in regulator return pipe – no idea how you would check this!!
ECU – the dark horse perhaps. Maybe it thinks it is giving out the correct modulated signal to the regulator, but in fact it isn’t. You would need an oscilloscope to check this.

So, how to proceed? Hmm, change the fuel filter if at all suspect. Not sure where the regulator return flow goes but if via the filter, perhaps a new filter housing too. Check the voltages at the rail sensor. Check the regulator is not dirty / O ring failed. Check the waveform to the regulator. Swap the ECU for a known good one.