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Discussion Starter #1
Hello all, I am having a problem with my lag 2. I was away for 3 months and when I got back she started with 3 seconds cranking as normal. I left it idling for a while and when I came back it had stalled. First time that has happened in the 4 years I've owned it. Started back up as normal and had no more problems driving around. Each day since it has stalled more and more and started taking much cranking to get going. I suspected air in the fuel lines but I will jump ahead in the story. I replaced the battery because it was on it's last leg. It became impossible to start except sometimes when I had given up I would give it one last try and it would fire up with 2 seconds of cranking and run fine. Next day dead again. I checked the voltage at the injectors. There was 6.5V with the card in. When I would crank the engine it would drop to 1V. I checked the resistance of the loom between injectors and ECU - it was 0.1 ohm. Good enough for me. I cleaned the earth points behind the left side headlight. When I checked the resistance of the loom there was no corrosion on the pins of the ECU. When the car is running I see the voltage at the injectors is 19V. I have connected my multimeter to an injector to try and see what the voltage is if and when it does start. I have not had it start yet but when I have been trying the voltage jumps around a lot. I believe the ECU is bad. I have located one on Ebay but I want to be sure it can be installed in my car. The part number is identical. I understand that I will have to take the car to the Renault dealer to have them program it but I have been looking at threads on the forum and they say it is necessary to replace the UCH and other components at the same time. I suspect that is the case if you don't want to go to the dealer - you need to get a full set of items from the same car for it all to work. So - my question is will a good used ECU be able to be reprogramed at the Renault dealer to work in my car without replacing other components? Thanks in advance for your answers.
Papy
 

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Super fantastic Mod Technical Supremo Nice Guy
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Short answer no.. LOOK for a virginized ECU.. immo code is inside the ecu , renault will not help,,
No use doing a voltage test across an injector, wont work , honest..
(And not as easy for me to explain, WHY it wont work and sure my interpretors ,the minute they see this will send my emails to spam for another few months)
Have you checked the tip of the crank sensor, ..
Before you condemn an ECU on a laguna, check this first..

Megane's and Clio's yes, terrible Earth systems on them, Laguna's only bad Earths are in the boot area.. But wont cause a non starter ..
So check the tip of crank sensor, for rust.. Check the Cam sensor back of the engine, timing cover side, clean this tip..
If you can get the car to run, then ECU is good, might not be the best, but its working.
 

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Discussion Starter #3
Thanks for the quick response ours. I had thought of checking the position sensors but I thought if they were not giving a good signal it would have set an error code but there is nothing. I will try cleaning the sensors today.
 

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Discussion Starter #4
Latest update - I cleaned both the crank and cam sensors. The cam sensor had very little dirt on it and the crank sensor had a layer of clutch dust on it. No rust, no oil deposits. I tried to start it with no luck. As I said before there are no error codes and I would think a bad sensor would trigger a code.

I tend to doubt that the ECU is bad because in the over 40 years working as a mechanic I have only come across one bad ECU and that was destroyed because the car had a water leak at the passenger door - it had rained heavily and the ECU was mounted under the passenger seat beneath 6 inches of water when the owner tried to start it.
Having said that - even though "ours" says voltage readings at the injectors are not a reliable indicator the fact that when I first instal the card and I have a reading of 6.5V but as soon as I begin cranking it drops to 1V is an indicator that there is high resistance in the circuit. It would be on the supply side. I suspect the output circuit from the ECU is failing and as soon as it is put under load the voltage drops. I will continue to try to start it and monitor the voltage at the injectors. I will also start searching for a "virgin" ECU. If anyone has any other ideas please let me know. As I say, in my experience a bad ECU is very rare but maybe I have hit the jackpot.
 

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Car laid up three months the first thing on my mind would be fuel, particularly condensation, separation and filter clogging.
 

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Super fantastic Mod Technical Supremo Nice Guy
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Can you get it start with Easystart/brake cleaner..
 

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Discussion Starter #7
It has been a very humid winter but the fuel filter has less than 10,000 km and I bled the filter with no indication of water. When it does start it runs fine. Thanks for the response.
 

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Discussion Starter #8
I have not tried. I will give it a go tomorrow. I suspect it will fire because the compression and timing are good but maybe it will actually start running again and I can do some more diagnostics. Thanks
 

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Discussion Starter #9
Can you get it start with Easystart/brake cleaner..
I don't have any easystart or brake cleaner but I figured a little petrol should do the job. Well - I guess I am getting old - I admit that I have had only had a small amount of experience with diesels before moving to Europe from the States several years ago but I would think that if there is compression, fuel and air a diesel should at least make a pop. It just cranks. I put my hand over the inlet to the manifold and there is good suction. What am I missing here?
Papy
 

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Super fantastic Mod Technical Supremo Nice Guy
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Cannot see your thread still via normal means ,,
Found it this way by going Advanced ( Old school forum member pointed it out )

Would try Easystart, or clutch cleaner, petrol will need a spark to ignite, where as diesel needs compression/heat to work ( combustion), as Easystart, or brake and clutch cleaner react the same way as diesel would still go on this method,
Just to get it back up and running...
 

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Discussion Starter #11
Can you get it start with Easystart/brake cleaner..
There is no Easystart for sale in the village where I live so it took a while to get a ride and buy some. I got the Lag to start with the easystart - it died after about 30 seconds but I was able to restart it immediately without the easystart. I let it run for about 10 minutes and shut it off to try and restart it. It would not start. Before, when I would get it to start it would restart afterwards with no problem. I am beginning to think the injector pump is failing. If so - this is the first common rail injector pump failure I have experienced. Is it common for them to intermittently start fine and other times not at all? I have ordered an iCarsoft RT II to help me diagnose the problem. I will get back when I have new info.
Thanks for all the assistance.:x
 

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Super fantastic Mod Technical Supremo Nice Guy
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Think you need to start a new thread, we cannot see this, :frown2:
On the forum :crying2::crying2:
Only reason I have seen this as got a reply in my email box..

We are not ignoring you, but If we dont see it pop up, then we dont think any new posts/replies have been posted..
Not sure if this will show in the main forum.
But it should show in your In box ( your email in box )
 

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hi

maybe im just lucky or has the prob been sorted, as i can get to pg 3, thought i would mention in case prob is now solved and may be working for others
 

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Thread Closed to prevent fragmented replies.
 
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