Sparks at start-up.. immediately dies.. HELP :(

[xAntiVenxm]

Hi,

been a while since a posted on here - started my golf rebuild this spring and after hours of reading through the maintenance section and replacing parts i STILL cannot get it to run properly..

Put the key in, turn it, starter motor goes and the first spark happens and then the engine immediately cuts out and you can hear everything wind down to a stop..

BUT if you put your foot on the accelerator and press down a bit, she fires up like nothing is wrong!

soon as you pull your foot off, she sputters to a stop.

So far I have replaced...

1) ECU Relay (#30)
2) Fuel pump relay (#197)
3) Vacuum hose (main one that goes from top of throttle body through a grommet and onto a box I think might be the ECU but i'm not sure.. its right in the middle under the plastic panel held in by rubbery plugs below windscreen)
4) Spark plugs all new
5) Dizzy checked for corrossion.. none found, looks very very new
6) Crank angle sensor replaced as old one was dead

Scan it with vag-com.... nothing. fault codes were cleared just in case, and re-scanned.. still nothing.

I am totally out of ideas.

Any suggestions?

[sharki786]

Immobliser problem. Is the chip in the key for the immobliser

[xAntiVenxm]

uhhhh...

the key's VW logo is a button.. which makes a light go on lol not sure what the chip in the key looks like? have a 2nd key with no button, just solid

[xAntiVenxm]

both keys have a little black bar looking thing, assume thats the chip?

[VW BUSH]

Clean the throttle body

[sharki786]

As bush has said clean throttle body, then turn ignition on for 30-60 seconds DONT TOUCH THE ACCELERATION PEDAL AT ALL!!! You should hear clicking or whirring noise.  Turn it back off. Then turn ignition back on and start the car.
what reg is the car and is the engine the same engine it has always had to a replacement engine?

[xAntiVenxm]

Ok, will give the throttle body a clean tomorrow and try starting it as you said.

its P reg, I believe it's the same engine it's always had - previous owners kept lots of logs and reciepts but never saw an engine replacement one. it seems to have been taken care of up until the very last owner who did nothing for a year!

[itavaltalainen]

Don't think it's immo issue, you can't keep engine running with throttle then... it would just cut out after starting first time without chip being recognised, run for 2-3 secs then cut out and not fire up at all afterwards (it would crank thou).

If cleaning throttle doesn't help you could check with vcds if throttle potentiometer works correctly.

[xAntiVenxm]

True, I have kept it running a long time using throttle, enough to get it from the rear of my flat to the drive round the other side to work on it.

I'm new to vcds, I've got a registered version but testing the engine 01 doesn't throw any faults.

I'm new to vcds so anything besides the auto scan or individually scanning parts I will need a bit of a guide lol.

Running problems aside I can't wait to get everything sorted so she can be driven.. been off the road since 2012! And I'd like to drive something other than a fiesta at the weekend haha

[xAntiVenxm]

As bush has said clean throttle body, then turn ignition on for 30-60 seconds DONT TOUCH THE ACCELERATION PEDAL AT ALL!!! You should hear clicking or whirring noise.  Turn it back off. Then turn ignition back on and start the car.
what reg is the car and is the engine the same engine it has always had to a replacement engine?

Right so cleaned throttle body.. checked the pins in the potentiometer and the other sensor behind it (not sure what it is) and they're clean.
gave the idle valve at the front of the block a clean for good measure, but it was pretty clean anyway..

Still the same problem

Turned the key for 60 seconds, it sparked first, then died, and the starter motor carried on whirring away..

every now and then the revs would go up a tiny bit as if it sparked up but only a few hundred revs then back to 0..

could start smelling petrol after i stopped at 60 seconds.. hoping its just because the pump is going but the fuel isn't being sparked?

tried it again, still no luck - exact same symptoms.

..any other ideas?? same thing, if i touch the accelerator a bit she fires up.

Just noticed today also that if i let it die, the oil light flashes.

read in the maintenance section that this is the crank sensor - that's already been changed