The V8 Owners Forum -

my engine is doing some very strange things again ..

it seems to run ok on LPG , but when i switch to petrol it fluffs about ..until i disconect the wires to the fuel then it runs ok and smooths out ...it's not running on gas because i disconected the pipe from the vaporiser , it the first thing i thought of

it just runs on and on ..and the fuel pump is not running and even when i disconect the fuel hose to the cold start injector there is no fuel coming out yet it still runs , as soon as i reconect the fuel pump ( you can then hear it running it starts to cough again

?? any ideas welcome please
it's a Flapper EFI

Sounds like you just invented perpetual motion

Ian

Keith.

I think youv'e just made a fortune, an Internal combustion engine that runs on air, downside is I think I can hear the petrol companies booking hit men to remove you immediately.

I'm clueless on LPG but it does sound like it's double fuelling, so runs ok when you remove one source or am I missunderstanding your post.

kevin.

if only it was that simple ...

it's got me well confused dot com ..

Sounds like you need to download this:
http://www.cowdery.org.uk/FlapperManual.tar.gz (all 118Mbyte of it!), and follow it through.

Chris.

hi Chris , link no working , is that the tests for the flapper setup ?

Sorry!, try this

http://www.cowdery.org.uk/downloads/Fla ... ual.tar.gz

Yes it is the Land Rover Flapper EFi fault finding and setup manual.

Chris.

right today i started it on petrol unplugged the fuel pump connection , then removed both petrol pipes ( feed and return ) from the fuel rail , also removed the LPG feed pipe to the mixer just in case in was robbing some lpg from soem where and it still ran , i even removed the vacuum pipe from the fuel pressure reg and it made no differance

HELP !

Hmm, this is magic Keith. You must be missing something I'm afraid!

If you're confident there's no petrol, then pull the 9th (cold start) injector fuel pipe.....

At least that must prove it's on LPG. You can tell from the smell of the exhaust which fuel it's on.

Chris.

just been checking the fuel pressure regulator ..
how do they work ?

when the engines not running are they open or shut ?

bodger wrote:just been checking the fuel pressure regulator ..
how do they work ?

Hello Keith,

Extracted from my website essay -

Fuel Pressure Regulator

• The fuel pressure regulator, located on a bracket adjacent to the rear of the RH rocker cover, is required to control the pressure of fuel delivered at the injectors by sensing variations in manifold depression or vacuum.

• This ensures the quantity of fuel released by the injectors is governed by one factor only - injector “open time”.

• Fitted in the excess fuel return pipe, close to the injector fuel rail with its fuel supply, it has two chambers separated by a diaphragm.

• One chamber contains fuel from the supply line. The other is linked by a pipe to the engine side of the throttle butterfly to sense manifold depression.

• At rest, the spring holds the diaphragm valve against the fuel return pipe.

• At full throttle manifold vacuum is low; the spring holds the diaphragm on its fuel return pipe seat so pump pressure must reach approx 36 psi to move the diaphragm valve against spring pressure allowing excess fuel to return to the tank.

• At idle and overrun, manifold depression is high. The fuel return is opened and pressure falls to 26 psi. Intermediate vacuums regulate fuel pressure between the minimum and maximum.

• Thus pressure varies between 26 and 36 psi according to manifold depression ensuring the amount of fuel delivered by injectors is governed only by injector “open time”.

more here:

http://www.vintagemodelairplane.com/pag ... ply01.html

bodger wrote:when the engines not running are they open or shut ?

By definition, with the engine not running the Fuel Pressure Regulator will be shut, to maintain the fuel pressure in the fuel rail at 36 psi with the fuel pump off, ready for the next start-up.

bodger wrote:then removed both petrol pipes... also removed the LPG feed pipe...

ok.. no petrol, no gas, whats the oil level doing? dropping? sounds like oil burning/dieseling to me if theres no petrol or gas making it into the engine.

Hi Kiwi , sorry to dought you there for a minute ... taken off the plenum and there is a pool of oil at the back

why would it be doing this ??

bodger wrote:taken off the plenum and there is a pool of oil at the back . why would it be doing this ??

Keith, That oil comes in from the breather system suspended in the foul crankcase air and condenses out over time to laze about in the plenum chamber, and always at the lowest point from where it can't escape, nor do any real harm.

If there is loads too much oil thereabouts then the breather system wire-mesh filter may not be working properly or the baffle plate inside the RH rocker cover may be missing or you have serious piston ring blow-by.

having cleaned out the plenum and put it all back together , it still did it ..
is it possible to have dirt in the injectors holding them open ?
just another thought

i ran it up to temp with the breather hose still connected to the flame trap but off the other end , quite a lot of mist , but it's really only water certainly not a huge amount of oil there if any ,
is there any other way oil could get up into the plenum??

i did try something else too
even though there are no pipes supplying fuel gas or petrol when i unplug the sense wire from the NEG coil to ECU , it stops running ! ?
and as that has nothing to do with the ignition system so thats not why it stops

welcome to the mad , tearing my hair out problem
more ideas welcome please