[caltamz]

Gday guys. I have 2000 baleno g16b engine in my sierra.
it was converted a couple of years ago and everything ran fine.
It started having an intermittent problem losing signal from the ecu to the fuel pump.
It has sat for about 12mths now but im trying to get it sorted.
I got it started with a high idle at first but now i have no signal to the fuel pump at all.
the fuel pump works fine its a bosch 044.
When the key is turned on you hear the relays click but thats it. engine still winds over and everything else is fine.
I get a voltage of approx 4v from the ecu to the relays.
Would the ecu be the problem or is there something else it could be?
Also what sort of diagnostic scan tool works with these engines?
Cheers for any help

[MrRocky]

Bosch 044 arnt designed to suck you really need a lift pump to a surge tank or use a mercedes pierberg pump that self primes up to 0.6m.
Bosch 044 is way to big anyway
Diahatsu feroza 1600 pumps also work well and are silent but they will all need a lift/pre pump and surge tank to live a long life except the merc pump.
I would wager your pump has sucked dry and died.
Pretty easy to check if its got power with a test light (keep in mind initial key on will only power for 4 secs or so)

[fordem]

No power to the fuel pump.

A relay is a switch, one relay switches power to the fuel injection system - injectors, ignition coils, sensors, etc., and the other switches power to the fuel pump - if I'm not mistaken the ECU energizes the relay by supplying a ground to one end of the relay coil, the other end of the coil being fed +12v from a fuse.

Ground the meter negative lead to a known good ground and probe both ends of the relay coil with the ignition switched on - the EFI main relay should have +12V on one side and close to 0v on the other (<1V), the fuel pump relay will most likely have +12V on both ends of the coil - crank the engine, whilst probing the fuel pump relay coil, you should see one end remain at 12V, whilst the other drops to near 0V.

If you are hearing the relays energize you should be seeing that 0V (or close to it) that I mentioned, if that's where you're seeing the 4V you mention, I would check & clean the ECU related grounds.

For a diagnostic scan tool you'll need either a TechOne (the dealer tool) or you can contact Rhinoman (http://www.rhinopower.org) and get one of his adapters and software to run on a laptop - the big question would be did the person who did the conversion include the OBD related wiring - if they did, it might also be possible to use a jumper to get the check engine light to flash the codes (see Rhinoman's webpage for more details).

[JrZook]

caltamz wrote:

When the key is turned on you hear the relays click but thats it.

So the fuel pump relay clicks but the pump doesn't run?
If so then the ECU is working as intended and you either have a problem with the wiring from the relay to the pump or the relay itself.

[MrRocky]

Pump can still work but just be a dud for enough flow.
That fuel rail needs to have so much pressure it mists when you crack the fuel rail fitting

[caltamz]

Cheers for the replies guys. I will check everything thats suggested and look for a coily tank as well.