robjenko

hi all, recently ive had trouble starting my completely standard 98 uk turbo classic. when starting it cranks over for a good 10 seconds before firing up no matter if its hot or cold and will only finaly start with the acellerator pedal to the floor.
just before this issue started, i replaced the fuel filler neck (as it was rusty and the breather pipe rusted off) and at the same time replaced both the oil, genuine oil filter and genuine fuel filter. about a week after changing these, it started becoming difficult to start.
since then ive changed the plugs and the battery and this has made no difference. its almost as if the fuel is draining back to the tank and is struggling to be dragged back to the front when starting. i have also taken the little valve out of the fuel cap to stop the vacum effect in the tank, incase this caused the fuel to be dragged back.
when turning on the ignition, the relay clicks and you can hear the pump prime the same as it has always done. when running, the engine is perfect, idles fine and theres no issues. theres never any CEL lights or faults.

any ideas guys?

cyman

Im pretty new to scoobies but normally the fuel runs round the fuel sytem back into the tank any and is controled by a vaccum controlled fuel oressure regulator. There maybe other common issues on scoobies but the first thing I would check is that you havent dropped any rust and rubbush into the tank that is givving priblems with fuel pickup and poss meaning you will be running a bit lean on the road aswell

cyman

Sorry for the spelling auto correct on phone

scoobyricht

iTrader: (4)

have u checked for codes?

robjenko

that was going to be my next thing to check so shows im thinking along the right lines, thanks.

yeah, nothing showing.

robjenko

had the pump out tonight and it all clean and clear.

anyone have any other thoughts?

alcazar

iTrader: (2)

Are you keeping your foot OFF the throttle when starting? You are not supposed to touch it until it fires, since it can flood if you do.

The cure to flooding is as you say...foot to the floor gently while cranking.

robjenko

for the 3 years ive owned, ive never touched the throttle when starting, its only now the only way to start it is to keeping pressing down until its on the matt, but its not flooding/fowling the plugs when started.

could it be the pump is on its way out, or is there a one way valve or something along the line to stop the fuel draining back?

merlin24

iTrader: (1)

Is the fuel pump any noisier than usual - normally a sign that's its on its way out.
Yes,there is a check valve on the pump outlet which maintain's line pressure in the system when the engine has stopped.

Mick

robjenko

not really, it sounds the same as it always has.

robjenko

problem is still happening. ive replaced the fuel pump for a new one but no joy. anyone got any other ideas?

bmw730i

Can you check the compression?If nothing else you would have piece of mind

robjenko

sorry should have said, we did that when i changed the plugs and no problems there.

ALi-B

iTrader: (1)

If iuts fuel pump....or pressure reg, do this:

Ignition on (imbiliser deactived). Allow pump to run (and stop)
Ignition off, wait two seconds
Ignition on. Wait for pump to stop again
Ignitition off
On
Off
On

you get the idea

Then see if it starts ok

Basically what you are doing is pre-priming and building pressure in the fuel system. If it works and starts ok, its likely your fuel press regulator draining all teh pressure back to the tank. Or you have a leaky hose...(incluing the ones inside the tank).

Fuel pressure guage will easily check this; 40psi ish. Should maintain that pressure with the engine OFF for at least a minute or two.


By the way...FULL Throttle will not the flood teh engine, it does the reverse...the injectors do not open when cranking with full throttle to clear a flooded engine

(unless you have a aftermarket ECU ).

robjenko

thanks for that, just tried that, on and off and primed it 5 times and then it fired straight up. outside the car it smelt strongly of fuel so im thinking there maybe a leaky pipe. i know that the ones under the bonnet are fine as ive checked them before including the ones that run to the injectors and the pipes on the cradle/pump in the tank are fine as ive had the cradle out and checked them and replaced the one off the pump to the cradle,so im next thinking the pipe from the cradle/pump that runs over the tank and back under to the metal pipes under the rear seat?

robjenko

well checked the pipes that run over the tank and they are fine, no smell of fuel under there when running either. fuel pressure reg next then

robjenko

fpr changed tonight for a known working one and after all the ballache of changing it, no change. anyone with a clue as to where i go next?