REV COUNTER ERRATIC

[DublinChris]

One or two other pointers that might be part of problems I am having .

1. The imobiliser on diesel pump was disconnected at the recent pump service two weeks ago and the old solenoid left connected to pump body.

2. About 2 years ago I replaced the ignition switch with a second hand unit so key/switch for ignition is not original.

3. With the erratic rev counter it all seems to kick off just when key is inserted in ignition and turned to on position - sometimes the key symbol light on dash lights up as well as if suggesting wrong key so I turn key back to off position and turn it back again to start. It only does this an odd time most of the time there is no key symbol lighting up.

Could there be any related issues with imobiliser having been disconnected and a fault recognising key at times. Car always starts and revs settle back to 1K.

Also pump was covered with coolant.

Would there be any connection with the recent eml light and rough running issues that also surfaced last wednesday?

Chris

[evilally]

Hi Chris, I think we need to know the fault code and description read by the diagnostic device. These have comparatively little in the way of electronics, I would still say this is relating to the NLS, it's connector or wiring.

[DublinChris]

Hi Chris, I think we need to know the fault code and description read by the diagnostic device. These have comparatively little in the way of electronics, I would still say this is relating to the NLS, it's connector or wiring.

From my understanding there was no fault code showing up on Citroen diagnostic device except for the aircon which I don't have. All the device showed was engine speed when engine not running.

I did not use car on Sunday or Monday and then today- Tuesday morning when I turned on ignition needle did not move until engine fired up and all was good. I drove car all morning stopping and starting about 10 times and every time it started and ran perfect - until just after lunch! I started on this occasion and needle shot around to max revs and back to zero where it stayed with engine running(first time its done that all other times it flicked around and came back to idle) eventually flicking back and forth from zero to max. The engine sounded rough - diesel rattle - but I drove off and eventually things settled. I had to stop on a job for about an hour and half and when I went to start car it was perfect again. EML was not on at all during day. I completed calls and headed home on M/way - all good but going down steep off ramp and braking hard at bottom EML came on and went off once I revved above 1.5K - 2K. No other issues except for light on that occasion

It just feels like "timing" of something going off from time to time. If I start car and there is no needle flickering then she runs good. If I turn key to start and needle flickers then probs start

[DublinChris]

I have a similar problem. When I start the engine, the rev counter will often flick all the way round the dial and then back to zero. It will stay at zero while the engine runs (with very advanced timing). Stopping the engine and restarting usually returns normal operation. I'll be looking into this tonight hopefully (I'm going to try another crank sensor). Interesting what you say about the coolant leak. I lost about half a litre of coolant when I removed that same hose to get access to glow plugs. I can't remember now if the problem started before or after this.

Did you manage to sort your own rev counter issue?

[evilally]

I'm not familiar with the diagnostic device used, but I would have thought that the fault would be stored for it to be retrieved. I think it might be a good idea to get a Lexia on it. Even if not stored, you might have a chance of capturing it by going for a test drive and having a passenger with a laptop. I don't know if you have a forum member near you with one to lend. You are exactly right about the timing, the NLS supplies data required for the ECU to set the injection advance. If you disconnect the NLS altogether, the pump defaults to a fixed +20 degrees advance and the engine sounds very naily/harsh. It sounds like the ECU is losing communication with the sensor, or the sensor itself is faulty.

[evilally]

I replaced the crank sensor but it hasn't made a difference. It does the rev counter flicky thing maybe once every 10 starts. I was out tonight and cleaned the NLS plug and ECU connector, time will tell!

[DublinChris]

I'm not familiar with the diagnostic device used, but I would have thought that the fault would be stored for it to be retrieved. I think it might be a good idea to get a Lexia on it. Even if not stored, you might have a chance of capturing it by going for a test drive and having a passenger with a laptop. I don't know if you have a forum member near you with one to lend. You are exactly right about the timing, the NLS supplies data required for the ECU to set the injection advance. If you disconnect the NLS altogether, the pump defaults to a fixed +20 degrees advance and the engine sounds very naily/harsh. It sounds like the ECU is losing communication with the sensor, or the sensor itself is faulty.

There is a lot of sense in what you are saying and will go down this avenue. It will be Monday before I can get mech to work on it.Still cant help but think that the coolant which soaked the NLS is at the root of the problem

the mech tells me that is diagnostic tool is similar to a Lexia but obviously it is not.

[evilally]

Yes, you might be right, and I find it odd that I lost a bit of coolant in the same area. I had a recurrence of the rev counter issue today, so I'll need to have a further think about this.

[DublinChris]

Yes, you might be right, and I find it odd that I lost a bit of coolant in the same area. I had a recurrence of the rev counter issue today, so I'll need to have a further think about this.

Well evilally! hard to know what to say at this stage. I had arranged to leave car in to garage on Wed but because of needing transport I decided not to leave it in and take my chances. As per usual first thing Wed morning she started perfectly from cold. I drove across city in traffic and then did some motorway work and finally to destination on country roads. A total of 35 miles without fault. So parked up for couple of hours but when I started her again things went haywire rev counter like yours swinging between zero and 6k with engine noise from advancing pump. I drove off and the rev counter stayed at zero and did not reset as previous. Stopped and started a few more times in afternoon and problem remained. In trying to turn engine on and off it did not clear anything, and there were flashes of key symbol as if ignition did not recognise key, this all by not taking key out and just turning on off while in ignition switch. So by chance I removed key completely from ignition and reinserted it and tried to start again and things appeared to reset. So continued home with no more problems. Well Thursday morning and this morning started her up from cold and both days I drove the full day stopping and starting without any issues what so ever No eml light - no jumping rev counter - no engine noise! Now I am due to leave her to garage on Monday morning but think I will see how it goes Sat and Sun and if all good might pass on garage.
I am wondering if in some way coolant has eventually dried out if that was a cause and things have settled down again? Like I have said before it all kicked off with the coolant leak up high above NLS and everything else including Diesel pump and solenoid etc down to alt belts. NLS might well have been affected by the coolant and also the disabled imobiliser.

I have probably tempted fate at this stage but fingers crosed anyway

[DublinChris]

Well all was going well - All through Thursday/Friday and on to Monday no issues apart from one small one on Sat when on one occasion when I put key in ignition the key symbol stayed on and there was a beeping soud as if key was not recognised. I removed key reinserted and all was good started with no rev counter or other issues. Monday morning again started fine and on up to about 1.30pm. Put key in to start and rev counter jumper around with pump advacing and "diesel" noise. So took key out and put in and out couple of times and everything settled so for rest of day all was good including so far today Tuesday. Strange thing that it always seems to be around midday that things go haywire!!?

Really hard to get head around this - but for now engine is generally running well just this intermittent madness around the middle of the day!

[Xantidote]

generally running well just this intermittent madness around the middle of the day!

Well,

You know what they say - "Only mad dogs and englishmen go out in the mid-day sun"

[DublinChris]

generally running well just this intermittent madness around the middle of the day!

Well,

You know what they say - "Only mad dogs and englishmen go out in the mid-day sun"

In this case its a mad French car and an Irishman

[evilally]

I had come on here tonight to ask if this was still going ok. There's a 406 in my local breakers, I'm going to nick the injector with the NLS on it and swap it out when I get time. It should be possible to change the sensor only by cracking off the top part of the injector.

[DublinChris]

Well I am almost afraid to tempt fate again but it has been a week and a half with no problems whatsoever. Starting ok everytime

Can only think that it was down to the coolant spraying around and now things have properly dried out so fingers crossed that's the end of it. Treated car to oil & filter change and new front tyres for being a good girl and she seems well happy now - pulling like a train 190500 miles up now

[DublinChris]

Well that's over 2 weeks now and the old girl hasn't missed a beat
Starting well every-time with no needle jumping or eml issues so the longer it goes like this I can only conclude that it was down to the coolant that has now well dried out