Mechanics

ENGINE STRUGGLING AFTER 5 MINUTES

1996 Renault Laguna

Engine Performance problem
1996 Renault Laguna Manual 123600 miles

I'm having a slight problem with my Renault Laguna. The car starts fine in the morning no problem, regardless of how cold it is or how long it has been standing there. However, after about five minutes, when I try to pull away from a junction the engine tries to die. I can stop this from happening by revving the engine with the clutch down. This happen for just a few minutes and afterwards the car runs fine for the rest of the journey. If I stop the car whilst it is playing up or around that five minute mark it is difficult to start (the starter motor turns over but does not fire). I have to leave it for about 10 minutes.
Some time last year I was getting a fuel smell from the engine and through the heater. I have checked the hoses and for leaks else were and all is fine. The smell disappeared after a few days. It returns now and again, but seems very prevalent at the moment. I mention it here as the to problems may be related. Thanks in advance for your help
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JohnMclean
January 30, 2009.




Hello. Thanks for the donation. Much appreciated

Does the CEL/MIL (check engine light) show at anytime on the dash display? Is it showing constantly? Check the fuel line connectors under the bonnet/hood. They tend to wear on older renault models and leak slightly and eventually pop off. Let me know
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Dave H
Jan 31, 2009.
Thanks for the reply. No the 'Check engine light' is not on, nor any other warning indicators. I checked the fuel hoses this morning and I can't see any leaks or cracking, nothing out of the ordinary at all.

It appears as though the fault only occurs when the engine is getting up to temperature. Whilst it is cold or once it gets up to temperature it runs fine.

Thanks again

Tiny
JohnMclean
Feb 1, 2009.
Firstly add a good fuel injector cleaner to the fuel tank ! This sounds like a fuel/air mixture fault. So you could try cleaning the MAF (mass airflow) sensor. Although the way you describe your fault I would be expecting the fault to be illuminating the CEL? Does this fault occur everyday or is it intermittent?

MAF sensor uses a hot wire sensing element to measure amount of air entering the engine. Air passing over the hot wire causes it to cool. The hot wire is maintained at 392 °F (200 °C) greater than ambient temperature, as measured by a constant cold wire. The current required to maintain hot wire operating temperature is proportional to the intake air mass. The PCM uses this current requirement to calculate the fuel injector pulse width in order to provide the desired air/fuel ratio.

Dave H
Feb 1, 2009.
Thanks for the reply again Dave. Yeah it happens every time I use the car, just as the engine reaches optimum temperature. You can set your watch by it, it's got to the point I know exactly when it is going to happen.

I'll take a look at the MAF sensor, thanks again

Tiny
JohnMclean
Feb 2, 2009.
You were spot on with the air flow sensor, the car is running fine now, thanks. All I need to do now is sort out the petrol smell. Thank again

Tiny
JohnMclean
Feb 4, 2009.
No Problem. The only thing I can think of with the petrol smell is the problem all renault's have with the fuel pipe connectors (plastic connectors). They were always popping off or working loose now and then. Also some models have a fuel filter located under the vehicle behind the bottom sill near fuel tank ! The connectors could be loose there?. It could also have been the vehicle MAF sensor was correcting the fuel overly rich (adding more) and this was causing the smell ! Let me know if the problem persist's. Hope this helps. Please spread the word of our assistance. Feel free to use the feedback portion at the top of this post !

Happy Motoring
Dave H

Dave H
Feb 4, 2009.

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