f**king stupid piece of sh!t WILL start! - SORTED AND RUNNING!

[Matty-MK3]

 

After the whole catching fire thing the other day all I've done is replaced the rubber mount thing and it kept turning over and not starting. When you poured petrol down the body it started. Pulled the fuel line off and petrol floods out  when you turn the key

Went round to a mates today and got a throttle body off a 1.4 breaker and went to put it on. There are two parts to the throttle body well the 1.4 was old pre-OBD-II and the sensors were all different and had less wires so I just used the top part.

Put it on it kicked a couple of times poured in some petrol and it spluttered then ran like an absolte dream. Turned it off went to start again and no go, easy start and it ran fine just didn't idle (I assumed as the induction pipes were all loose) and now we're back to square one.

Turn over and over put force petrol in there and it goes fine.

I phoned my boss and he said it sounds liek the ECU is cutting the fuel/SPi after start up. This does sound feasable but any ideas why and how to solve it?

I'll put it on a code reader/VAG-COM tomorrow. Cheers. 

[Christo77]

In all honesty ole chap i couldn't point you in any direction really..other than to say stick with it, bit of encouragement anyway   sounds like you'll get there..

[Khare]

air leak somewhere?

[Matty-MK3]

Thought it could be an air leak, but the thing is when it was running sweet, the only thing over the T/B was a plastic cover, wasn't even bolted down, but it still ran fine.

Putting everthing back and still not right. Dribble petrol down there and it'll run all it wants, stop dribbling petrol down there and it cuts straight out.

Got to be a fuel problem and I can only think of two things:

ECU is cutting the fuel pump out after cranking, the relay clicks on igntion then about 8seconds later clicks again (off) which is normal unless I'm mistaken... I haven't tried cranking for a while with the pipe off yet.

The ECU is stopping the injector opening. I'm wondering what would happen if I added 12V to the injector, I would try but I'm scared of it sparking and going up in flames.

[Khare]

if it runs when you pour petrol down then its either underfuelling, or there's an air leak...or overfuelling.

My guess would be air leak.

you have the SPI right? Has the rubber flange between throttle body and intake manifold, correct?

[Matty-MK3]

It does have the rubber flange, I've just changed it.

The thing is, it doesn't smell of fuel at all.

When I put the new TB on it stunk of fuel when it ran. Now were back again and it doesn't smell of fuel. The rubber flange is on well and tight.

You can kinda tell it's fuel from the way it's cranking, when it gets fuel the starter motor either judders or spins faster, ATM it doesn't.

Pulling the fuel pipe off has 0 effect.

[Khare]

Righto - No smell of fuel at all would indicate underfuelling due to air leak, so again, I still think it's air leak related.

try starting it, while you cover with your hand some of the throttle body. Try different amounts, like cover 1/2, then 1/4 then a tiny bit, till it starts. If it doesn't then try removing spark plugs and cranking it over for a bit. See if you get a load of fuel shooting out. You might have flooded the engine.

[Matty-MK3]

Yeah I see where you're comming from I guess.

I know for a fact the engine isn't flooded.

I have to admit what you're saying is making sense. The seal around the throttle body is a bit rubbed out. What doesn't make sense to me is when all the induction was off it ran fine. The throttle body top/cover wasn't even bolted down at all.

You are making sense though mate, cheers. I think I'll put it all back and go from there checking individual pipes etc. I will put VAG-COM on it tomorrow though!

Cheers!

[Khare]

Don't think vagcom will tell you much.

Doesn't matter if the induction piping and box was unbolted, what matters is the amount of air that gets past the butterfly, that air is not taken into consideration by the butterfly so the ECU can't adjust accordingly.

Think of it like the MAF, it sets a ratio fuel:air. If that ratio is disturbed it won't run properly or won't run at all.

[Matty-MK3]

Yeah yeah I get it cheers mate.

I've been thinking about this a bit. Just the car will actually run rougher if the induction is all off, it just isn't quite the same. The throttle body, both parts are fully air tight. I've checked about 8 times.

One pipe I've just thought about is at the bottom of the TB there is two pipes, one leads all the way down near the airbox, but doesn't actually connect to the air box. It's a fairly thin pipe what's that? Just wondering if that's connected down bottom, one thing I haven't checked.

Cheers.