C5 X7 Changed crank sensor now wont start. Help!

[Peter.N.]

Had a flat spot on the throttle and intermittent stalling, I was assured it was the HP diesel pump which I changed, still did it. I was again led to believe it was the crankshaft sensor, changed that and it wouldn't start, refitted the original and it still wont start. Could anyone help. I have tried two Lexias and neither will work.

Thanks

Peter

[wheeler]

Just to confirm it was running before you replaced the crank sensor?
Any chance that the magnetic pickup has been damaged?
Have you re checked for damaged wiring connections?

Failing that you will really need to se some live data from the sensor

[Peter.N.]

Thanks, this is the problem I can't get either of my Diagboxes to work on the car or the two other C5 X7s we have. I have tried two new sensors neither will allow it to start, I have now refitted the original and it still wont start, turns over fine, fires up on easy start but won't keep running.

After 40 years of hydropnumatic ownership I am seriously thinking of jumping ship.

Peter

[mickthemaverick]

If it fires up on easystart then that suggests a fuelling issue and you have replaced the HP pump. Which engine are we talking about on this one Peter?

[Peter.N.]

2.0. Hdi.. I am pretty sure its an electrical fault mick. When I changed the first sensor it wouldn't start at first but after several attempts it did fire up, got to about 2000 rpm and stopped. The fuel is getting into the pump OK but I don't think its reaching the injectors.

When we were going to Scotland it occurred to me that it might possibly be something to do with the MAF sensor, so I unplugged it and it ran perfectly for about 1200 miles, it the started stalling every time I stopped, I plugged the MAF back in again and it improved the stalling a bit but started flat spotting again. I think there is a signal reaching the ECU or missing that is preventing the injectors from opening. It was 'flat spotting' before I changed the pump.

I am just pleased I didn't change the sensor before we went away. It seems to have been changing the sensor that precipitated the non starting, it was perfectly OK when I drove it on the ramp but after changing the sensor it wouldn't start.

Peter

[mickthemaverick]

Have you tried swapping a MAF sensor from another car?

[Kees]

Maybe you just have to clean the MAF sensor, there is a YouTube how to do this.

[mickthemaverick]

Basically you disconnect the sensor, take it out of the car with housing and then give it a good dousing from both sides with MAF cleaner. It did make a significant difference to the C5 I had. https://www.ebay.co.uk/itm/393048529165 ... R87-sqn_ZQ

[CitroJim]

Sorry to hear your car is causing a bit of grief Peter... First thing I think is to try and get your Diagbox working.

Happy to help with that if I can. What does Diagbox say when you try to run diagnostics and what version of Daigbox are you running?

[Kees]

Be careful with cleaning, there's a tiny filament inside.

[Peter.N.]

Hi Jim, nice to hear from you. I have 2 Diagboxes and three cars and no combination will work. You get as far as the menu but when you try to select a section it just comes up with all these numbers that are supposedly missing and you can't go any further.

These two Daigboxes were they both yours Mick or did I put a different one in the box as well? I know I had at least one that used to work.

Yes I know about MAF sensors and very often if they do go faulty, disconnecting them usually fixes the problem although I have successfully cleaned a few with carburettor cleaner. I have never known one stop the car from starting though. I think the ECU has a default setting that it reverts to if it goes faulty.

Peter

[mickthemaverick]

As I remember Peter you had one system which had failed and I had sold my C5 so I gave you my laptop and interface lead which were working when I last used them. I believe it was diagbox V7.62 but I wouldn't swear to that!!

Jim and I are hatching a plan to possibly come down on Thursday next week with Jim's fully functional system and see if between the 3 of us we can get it sorted. However we cannot confirm it yet due to other possible demands that may arise on Monday. Would that be helpful if we can do it?

[Peter.N.]

That would be brilliant Mick, if you can make it let us know about when to make sure we are here. Look forward to seeing you both if you can make it.

That other Lexia must be mine then but they are both displaying the same symptoms, it has the same numbers on it as mine.

Peter

[CitroJim]

That would be brilliant Mick, if you can make it let us know about when to make sure we are here. Look forward to seeing you both if you can make it.

It'll be great to see you again Peter and if we can get both your car and Lexias running then that'll be a lovely result

Meantime, have you left the battery disconnected for an extended time to see if that will allow everything to reset back to scratch?

[Peter.N.]

Hi Jim

No, its on charge at the moment but I will. It needs a BSI reset I can't close the windows, not the first time! Shan't do much today as we shall be out for most of the time.

Peter