cold starting problem

[kevh]

Hi All
When i get in the car in mornings turn the key starts up fine revs go to about 1300 after about 20-30 seconds revs start to full as normal but then idle very erratic goes from About 1000 to almost stalling i have to keep revs high with accelerator to stop it stalling after about 5 mins all OK runs on its own.
any ideas?

kevh Leon Cupra 1.8T 03

 

[andycupra]

could be any number of things.
temp sensor or maf would be my first guesses.

 

[kevh]

could be any number of things.
temp sensor or maf would be my first guesses.

temp runs normal when warms up.
kevh Leon Cupra 1.8T 03

 

[Shaunyboy]

Wouldent say maf, as a maf is more likely to cause a dead spot in acceleration, my guess would be temp sensor, on the gearbox side of the engine, in the top of the water flange. There are 2 elements in the sensor, 1 is to give a gauge reading and one is for the ecu data. Likely that your sensor has gone and is giving the ecu a duff reading.

 

[traumapat]

Sticking throttle body , maf or temp sensor would be my guess.

 

[kevh]

engine light came on a few days ago with error" long term mixture lean" cleared fault, light been of 4 days came back on today. not checked fault code yet.
kevh Leon Cupra 1.8T 03

 

[traumapat]

Id try disconnecting the maf and see if that cures it... if it does its new maf time.

 

[kevh]

Id try disconnecting the maf and see if that cures it... if it does its new maf time.

when you say disconnect th maf do mean the plug or the whole thing?
kevh Leon Cupra 1.8T 03

 

[traumapat]

unplug the electrical connector on the maf housing.
http://www.seatcupra.net/forums/showthread.php?t=101577&highlight=grease&page=14

post 262 ... the tip of the maf arrow is on the connector you unplug. from memory a flat bladed screw driver is needed to compress a tab. There may be better pics of the connector within that thread.

 

[AntneeUK]

[offtopic]Sorry Kev, but are you typing in your signature every time? "kevh Leon Cupra 1.8T 03" doesn't appear like everyone else's sig[/offtopic]

 

[kevh]

[offtopic]Sorry Kev, but are you typing in your signature every time? "kevh Leon Cupra 1.8T 03" doesn't appear like everyone else's sig[/offtopic]

yes couldn't find were to add signature in profile.

 

[Shaunyboy]

What colour is your temperature sensor? Seriously i dbout its the MAF as main sensor for cold start is the coolant temp sensor, dont just unplug sensors and see if its better. Temp sensor is located on the geatbox side of cylinder head on the water flange.

Does it drive ok once warm?

 

[kevh]

What colour is your temperature sensor? Seriously i dbout its the MAF as main sensor for cold start is the coolant temp sensor, dont just unplug sensors and see if its better. Temp sensor is located on the geatbox side of cylinder head on the water flange.


Does it drive ok once warm?

yes drives ok when warm
the temp sensor is black no trouble starting this morning but ambient temp above freezing.
also found a split vacuum hose there are 2 coming out underneath inlet manifold the one on the right has split not sure were it goes to looks like it goes into a plastic block.

 

[Shaunyboy]

Doesnt neccaserily cause starting problems as such, with mine it caused it to rev up to 3k then missfire at 1k.

Split vaccum hose is the most likely culprit to cause a bit of a missfire as your sucking in extra un-metered air.

If it drives ok when warm, no flat spots then its not the maf tbh. Reason for the maf to cause a flatspot is it helps calculate the ammount of fueling needed when the engine in underload, by telling the ecu the exact ammount of air going into the engine, its not really important on idle as there is no load on the engine.

Id go with either your split hose, and/or temp sensor.

 

[andycupra]

split house could be it then, -- which could in turn effect the maf sensor reading (or at least how it compares to the actual volume of air engering inlet manifold) which in turn may have contributed to the error you got.

get the hoses replaced asap and see if that cures,

 

[Shaunyboy]

A leak after the maf wont affect its reading what so ever, it will just lean the mixture out, which inturn is picked up by the lambda sensor throwing up the lean mixture fault. Dont touch the maf if it drives ok as it will just throw more errors up, disconecting things isnt the way to diagnose a fault.

If its split right near the manifold, for example fuel pressure regulator, or recirc valve hose, and there is enough slack, simply cut the split part off and re-attach it.If its further down the hose then get 1m of silicone hose and just replace it all. Can either get black for oem look or blue etc.

If its part of the PCV system then its a trip to dealers for a new hose.

 

[andycupra]

agreed, im not saying the maf would read incorrectly and need replacing, but it would alter whats happening compared to what its reading, ie the maf is saying x amount of air is entering but due to a leak the volume ends up being y... thus potentially the fault regarding mixture.

So replace the plit pipe / repair asap and see how it goes.

 

[kevh]

contacted dealer today they say i cant buy just the split pipe i have to buy the whole assembly that includes some sort of pump/valve they gave me a part number" 06A133751AE " and quoted me £52 + VAT anybody got any ideas the pipe is damaged beyond repair.
kevh

 

[cupradarren]

cutting out

hi there i have a 2003 leon cupra when i left work this evening i started my car from cold and i cut out straight away and it smelt of fuel so i tried again and it cut out on the fourth time i held the revs around 4k for around 20seconds and it seamed to idle ok can anyone help with wot could cause this many thanx

 

[kevh]

still have cold start problem. i have changed split pipe under manifold, replaced temp sensor, checked throttle body thats all nice and clean. all out of ideas now. anybody had the same prob? starts ok but unless i let it idle without touching accelerator for 3 or 4 Min's it coughs and sputters until it warm.
kevh