Meg 1.6vvt low power, hard to start when stood.

[daverobzippy]

Hi . I am looking for some advice with regards our megane , it is a 55 plate 1.6 with 28500 miles on the clock. It had the dephaser replaced last year at renault and has been serviced in accordance with renault guidelines.
It has been gradually getting harder to start , makes no difference wether it is hot or cold, only time it will start perfectly is if it is restarted within a minute of switching it off.
Takes it 5 - 10 seconds to catch and it only seems to catch on a couple of pots at first then once fired up ticks over normally.
When driving it is low on power and feels very flat, feels like fuel starvation, doesn't misfire or pop back just very hesitant to go..
No management lights have appeared on the dashboard and there are no codes, stored or pending, in the obd
the clue i feel is in the way it will restart normally unless it has been stood.... want to try and avoid having to go to renault as i dont want slapping...
anyone with any ideas????
thanks in advance
Rob

[jowett69]

try cleaning throttle

[daverobzippy]

throttle body cleaned (wasn't what i'd call dirty to start) unfortunately this has had no effect. plugs are all a nice chestnut brown, gonna check short and long term fuel trim readings this afternoon, will post them on here when done!

[daverobzippy]

Ok . dropped the oil this afternoon as was due as change it every 6 months... took it for a run and ran a bit better but not perfect... brought it home, plugged it into laptop to do a log file of a run out, had it ticking over for a while on the drive then went for a run... ran like a bag of spanners.. popping back , no power.. have a log file of all values if anyone knows how to attach a spreadsheet file here ( and knows how to use office as i haven't much idea on that one.

Ignition Timing Advance for #1 Cylinder 18 deg 18 deg
Calculated Load Value 82.75 % 82.75 %
Engine Coolant Temperature 190.4 deg F 88 deg C
Short Term Fuel Trim (Bank 1) 39.06 % 39.06 %
Long Term Fuel Trim (Bank 1) 25 % 25 %
Intake Manifold Absolute Pressure 14.35 psi 99 kPa
Engine RPM 2193 rpm 2193 rpm
Vehicle Speed Sensor 44.38 mph 71 km/h
Intake Air Temperature 114.8 deg F 46 deg C
Absolute Throttle Position 84.31 % 84.31 %
Oxygen Sensor Output Voltage (Bank 1 Sensor 1) 0.02 V 0.02 V
Short Term Fuel Trim (Bank 1 Sensor 1) 39.06 % 39.06 %
Oxygen Sensor Output Voltage (Bank 1 Sensor 2) 0.09 V 0.09 V
Short Term Fuel Trim (Bank 1 Sensor 2) -100 % -100 %


above is a small snap shot of parameters with vehicle running on road, spreadsheet contains full log.
would be very greatful if someone with a clue about this could have a look...
fuel trim seems way out, at what point does this throw a dtc.... any help would be appreciated... thanks in advance

[davelowe]

PM or email me the full log. I can sort you a few graphs out (Alex will be wanting to do the same). Where were you driving at 46C?

[daverobzippy]

pm 'd you for your email address!!! yeah all through the log the intake air temp never drops below 40.

[steven-white]

the couple of times ive started mine, i think it may not catch. after i push the start/stop button, the engine comes to life and once ive released the button, i feel the engine has a hard time waking up lol hasnt died yet, but am wondering about the throttle body too. the engine starts fine, but staying alive could be a problem. i have same model as you mate.

[daverobzippy]

3 years late with my reply but it was the fuel pump at fault..

[jowett69]

3 years late with my reply but it was the fuel pump at fault..

LOL better late then never

[AlexB]

Makes sense. Fuel trim more than +10% plus the wide open throttle mean starvation of fuel. This affects cold starts, as they require richer than usual mixture.

3 years late with my reply but it was the fuel pump at fault..

[daverobzippy]

The reason it was hard to start when stood was the fuel in the line was returning to the tank. Add to that the pump not delivering a decent flow and bingo.