starting problems when warm/hot

[ahmeth05]

Hi there i'm new to this so forgive me if this has already been asked. the problem i have with my megane 1.9dci is that she doesnt want to start when warm/hot, its got worse this past month, took to renault where they had it for a week said they couldnt find the problem at first then finally they turned round & said it could be the UPC, injection computer, but then they said its not guaranteed that renewing this will solve the problem. Thats a very expensive IF.... especially when they said it would cost £785 to order & fit, as i havent got that amount of money burning a hole in my pocket. Please someone help as i really cant afford to buy another car. Thanks in advance for any advice.

[WebCode]

Ok in this case my first test would be to monitor the fuel pressure when the engine is being cranked.. If it looks low/lowish then an Injector Leak-off (leak back) test should be carried out..

The bosch injectors do fail and will show up as excess leak-off and therefore causing low fuel pressure on the common rail at cranking, so causing poor starting irrespective of whether it is Hot or Cold..

Don't let the dealer fob you off, ask them if they have done the test above if not ask them why!!..

The leak-off check takes 10 mins to complete..

Don't paying out for anything until they have confirmed that the fuel pressure is OK. It sound s like they are clutching at straws.

Ask for the fuel pressure readings at Cranking and when the engine is running.. Post them here..

[ahmeth05]

thanks webcode i'll try and get that done and post the results

[ahmeth05]

Hi webcode just got off the phone with renault regarding starting problem and the technician's reply was that test wasn't done because its an electrical problem and not a fuel problem.
Looking through this forum i've read other peoples problems regarding non starting, would it be an idea to have the throttle body cleaned at all? If possible can you post a picture of it so i can identify it in the engine bay. Thanks.

[AlexB]

Disconnect the temperature sensor to make the glow plugs glow when hot. If the engine starts, then the problem is related to low fuel pressure. Don't forget to connect the sensor back!

[ahmeth05]

Hi all, just an update re: starting problems, took the meggy to an auto electricians hoping & praying that it'd be a loose wire somewhere but nooo........They re-confirmed what renault have told me that its the injection computer. I can't even go to the breakers as the unit has to be programmed to my car . Some one please....Help. Looks like i'm gonna have to bite the bullet and get one Any ideas anybody???????????? Thanks in advance.