nova xe idle/running/fueling problems

[paulnova]

hi guys,

over the last two weeks i have been attempting to get my xe nova running. first problem was fuel not coming back down the return. a new pressure reg on the fuel rail fixed that.

now if i turn my fuel pump (GSi/SRi pump) on, i cant get the engine to fire, if i turn the pump off, engine will fire but will idle excessively high (around 4/5k)
and will keep on running without pump on (very strange) once the engine is running if i turn the fuel pump on, the engine cuts out, it wont let me rev the engine with pump on or off, only if i very gently put my foot down whilst switching pump on.

i have a spark, have cleaned and changed icv, gone through a starter motor trying to get it running lol!! cant see anywhere it could be drawing air from.
i think i have fuel lines right way round- fuel in on right hand side (19mm nut) and return on the left (17mm nut) when looking at engine from front of the car??

i was thinking the fuel pressure may be too high. seems as though the engine floods when pump is running, it just cuts out with big splutters! i have put a pressure regulator inline after the pump to try and lower the pressure, but it is no different.

me and my dad have been tearing our hair out over this. i hope someone can point us in the right direction or has had a similar problem themselves.

thanks. paul :thumb:

[paulnova]

nobody got any ideas??

[paulnova]

had a thought, would injectors maybe leaking under pressure?? does this sound plausable?

[Adam]

The return comes FROM the regulator on the rail.

How can it run with the pump not running? It will run for a few secs then die yeah???

[Lee]

It keeps running with the pump off???? How??????

[paulnova]

believe me im just as baffled how it runs so long without the pump off!! well just been having a tinker, thought i'd check the simple things...such as return line blocked (even though it is a brand new line) and i found that where the plastic pipe went into the rubber pipe to connect to the tank, the jubilee had crushed the plastic pipe, thus blocking it!! thats now fixed, ran fine for a while, then started to run rich again and cutting out. i still think there is too much pressure in the line, cant see the pump being at fault because i tried it on my 1400sri and it was fine. any ideas??

[paulnova]

i also think my new second hand fuel rail pressure reg may not be working corectly, i have been told pumps can run up to about 5bar+ and obviously the reg on the rail keeps the pressure down to 2.5-3bar. this probable explains why it runs for so long after the pump is turned off, the injectors opening will relieve the pressure!?

any ideas will be very helpfull and will keep you updated on this one as it is very strange lol