Help!! mk3 golf gti suddenly won't start?

[danny_p]

they'll start and run with NO oil or oil pressure.  they'll even drive for a while

[muzo26]

      Just an update, car still won't start checked oil level, pressure and sensors all fine.
      Can anyone tell me how to check the temp sensor? as i think the car is overfuelling, i have used nearly a quater of a tank of petrol just trying to get her started. And would i be correct in saying the temp sensor tells the ecu how much petrol should go through engine on startup.
      I noticed the last couple of weeks that i have been using more petrol than i usually do, and the day before she decided that she would not start she was running like a pig on 3 cylinders.

[boneybradley]

      Just an update, car still won't start checked oil level, pressure and sensors all fine.
      Can anyone tell me how to check the temp sensor? as i think the car is overfuelling, i have used nearly a quater of a tank of petrol just trying to get her started. And would i be correct in saying the temp sensor tells the ecu how much petrol should go through engine on startup.
      I noticed the last couple of weeks that i have been using more petrol than i usually do, and the day before she decided that she would not start she was running like a pig on 3 cylinders.

temp sensors do fail fairly often and a new one is around £10 and it does send a signal to the ecu which then decides how much fuel to give dependant on temp

[muzo26]

  Another update, car still won,t start changed both relays again unplugged the temp sensor because i thought it was overfueling but no joy. the car sounds like it wants to start because when turning it over it sounds like only 2 cylinders are firing and the revs pick up to about 600rpm but shuts down once i let the key go. Any suggestions please?

[sharki786]

sure you aint bent a valve(s)? get comp check done to it or vag com

[Len]

Have you take each plug out in turn to see if its firing?
Then whilst its out do a compression test.

[dashey]

i had the same problem but changed the coil pack and spark plugs this morning and all is well if it is a weak spark it doesn't run very healthy

[STOMMO]

Ive been having the same problem. Since the cold weather arrived the car wouldnt start  overnight until id turned it over a good few times,very frustrating and untrusting times.It used to start straight away, no problems ever. Now then........when i was trying to start it i would pump the accelerator like you do. I know I wasnt flooding it. It would try to fire but just wouldnt catch, if you know what I mean. I got to thinking. If everything is in correct place and all sensors are working eg crank and hall sensor etc. The ecu should know to start it without me pumping the accelerator..Went out his morning after the car had been stood for 12 hrs on the drive and tried to start it with no help from me on the accelerator. It started first time!!!!! Could I have been confusing the  system by me pumping the gas? Just a thought. I know I wont be doing it again.

[javalin]

crank sensor?

[muzo26]

  I,ve sorted it out eventually but i got there in the end. It was the leads arking out on the connection to the dizzy, pinched the connections a little with a pair of plyers and hey prestow started like a dream. With the moisture and bad connections the car would,nt even fire it just turned over and over, but it started to fire a little after a couple of days which meant the leads had dried out a bit. So the last time i was trying to start it my bro had his head under the bonnet and he noticed the dizzy was glowing ( it was 8 o'clock at night).
  So i've put new genuine vw dizzy,rotar arm and leads on it and she runs like a dream, i would,nt trust the cheap aftermarket stuff again.
  Thanks to all those who took time read my post and give me a few suggestions and i hope this helps someone with the same symptoms.