M4tty 2 Posted June 17, 2014 Report Share Posted June 17, 2014 The car starts 9 times out of 10, the 1 time it doesn't, the engine cranks as it should but doesn't fire up. The oil light flashes (but read this could be anything as it flashes when the oil pressure is below 10psi!?) I'm guessing there's fuel and spark as it starts sometimes? Unless it's a faulty connection, I've never had a chance to look at a faulty spark or fuel as it starts when I want to check! It only ever seems to do it when I've driven for a short period 4 miles or less, stop engine off and if I return to the car within about half an hour it doesn't start! If I come back to it after a few hours it starts! Any help would be great thanks M4tty 1 Link to post Share on other sites
gazeebo 3 Posted June 17, 2014 Report Share Posted June 17, 2014 Could be a faulty crankshaft sensor...happened to my VR6.Car wouldn't start if I turned it off then tried to start it immediately...had to wait until it had cooled down before it started again. Link to post Share on other sites
M4tty 2 Posted June 17, 2014 Author Report Share Posted June 17, 2014 My thoughts have been cps too just wanted other opinions, also thought coil pack( which was replaced October time though), currently trying to get vcds to work to see if it brings anything up Link to post Share on other sites
Sean_Jaymo 11 Posted June 17, 2014 Report Share Posted June 17, 2014 My 24v did this. Pretty much exact symptoms. New crank sensor cured it. Link to post Share on other sites
M4tty 2 Posted June 17, 2014 Author Report Share Posted June 17, 2014 Engine speed sensor came up on vcds, cleared it and never came back but guessing it wouldn't until this problem came back! A trip to vw for the sensor and see what happens, thanks for the comments! Link to post Share on other sites
Sean_Jaymo 11 Posted June 17, 2014 Report Share Posted June 17, 2014 The engine speed sensor will always come up. It's a quirck of the ecu. If you scan it with the engine off, it will throw a fault code to say the engine speed sensor isn't registering any engine speed. It won't be because the engine is turned off. It will self clear when the engine next starts. You only have problems if you have an engine speed sensor fault with the engine running. More often than not a crank sensor won't flag a code if it's a intermittent fault that switches the engine off. Link to post Share on other sites
M4tty 2 Posted July 15, 2014 Author Report Share Posted July 15, 2014 Got the sensor from vw and fitted, and it's done again! Starting to get annoying, gonna go over wiring and relays again sharki 1 Link to post Share on other sites
sharki 2 Posted July 15, 2014 Report Share Posted July 15, 2014 (edited) EDITED:Try a new ecu RELAY. Do you hear the fuel pump prime when it does this? If not then replace the fuel relay aswell. Edited July 15, 2014 by sharki Link to post Share on other sites
M4tty 2 Posted July 15, 2014 Author Report Share Posted July 15, 2014 Yeh I can hear it, I'll try the ecu relay, where would be best to get relays? Link to post Share on other sites
M4tty 2 Posted July 16, 2014 Author Report Share Posted July 16, 2014 Just had a look couldn't find anything I could see, also I'm running obd2 so don't have an ecu relay which is the norm I've read Link to post Share on other sites
sharki 2 Posted July 16, 2014 Report Share Posted July 16, 2014 (edited) Dealer is the best place to get new relays. I had this problem and it turned out to be the ecu relay.But that was on my 8v gti. Edited July 16, 2014 by sharki Link to post Share on other sites
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