Twin Turbo VS Ecotec Build **engine build in progress page 16**

[IBLOWN]

Loom done.

30A relay with built in fuse. I'll run a 20A fuse in it.

Power and earth cables are 5mm. Yellow is the signal wire. I'll splice it into the in-tank wires in the original wiring.

Now just got to put it in and give it a kick in the guts. Its probably going to run rich as hell, but it will be straight back to the tuner for a touch up.

All its got to do is just drive 50km to get to the tuner. I started it on the weekend just running off the in-tank pump and it ran fine. The fuel pushes through the Bosch 044 even though its not powered. If it wants to foul the plugs or something i'll just pull the fuse out of the relay and drive the car there on the in-tank pump.

 

[IBLOWN]

Ok so the pump install is done.

Took it for a quick spin and noticed it feels stronger BUT its still pinging. Less ping but its still there.

Went home and connected my fuel pressure gauge.

Holy McShit, its running 85psi at idle!!!!

I don't quiet understand whats going on.

Im running a stock regulator. My tuner prefers to tune on stock regulators so nobody mucks around with pressures afterwards. He's also tuned on stock regulators running Bosch 044 pumps.

Ive got two possible causes: The Bosch 044 is just too much flow for the stock regulator or the fuel return line is too small.

The other thing that doesn't make sense is why the hell is it running so good and not flooding even at idle now that the pressure is so high????? That to me really doesn't make sense.

I pulled the fuse out of the 044 pump and ran the car off the in-tank pump pushing through the 044 and pressure was only at 35psi. I gather this is because the intank pump is pushing through the 044. This confirmed two things: The pump is an animal lol and the gauge works fine.

Maybe it still pinged because the pump is only rated at 75psi and at such high pressures as its running now the pump has lost too much flow? I dunno.

Now ive just got to work out what the eff is going on????!!!!

 

[chargedvx6]

The injectors will only allow required amount of fuel according to tune based on what the O2 sensors are telling it. Go for the re tune and I'm tipping it will be fine. Only way to check if the return is a restriction at idle would be to fit a pressure gauge to the return line. For me anything out of an 044 has to be -8 right back to the return to surge and especially into the stock fuel tank

 

[IBLOWN]

The injectors will only allow required amount of fuel according to tune based on what the O2 sensors are telling it. Go for the re tune and I'm tipping it will be fine. Only way to check if the return is a restriction at idle would be to fit a pressure gauge to the return line. For me anything out of an 044 has to be -8 right back to the return to surge and especially into the stock fuel tank

Speaking of return lines, I think I may have a small routing problem lol... Ive got to check my line routing and make sure I haven't done something silly.

When I pulled the fuse out of the 044 and ran it off the in-tank pump I really shouldn't have seen ANY pressure at the rail let alone the engine starting. The fuel should have gone straight out the return on the surge tank and gone to the fuel tank. I think the surge tank may be pressurising which would explain the stupid rail pressures im getting with the 044 running.

 

[IBLOWN]

Lines are 100% correctly connected.

Surge tank overflow goes back to fuel tank return, rail return goes to surge tank.

I checked pressure at the rail and im getting 85psi at idle!!!

I pulled the fuse out of the bosch pump and ran the car off just the walbro and got 25psi.

I stopped the intank pump, made sure the surge tank was full, ran the car off just the bosch pump and got 60psi.

I was thinking from these tests that the return to from the surge tank to the fuel tank wasnt big enough.

Heres where things get weird: I checked pressure between the surge tank and the fuel tank with both pumps running and got 25psi! I was starting to think 100% the return is restricting back to the tank. The whole surge tank is pressurising!

I stopped the bosch pump and ran with just the intank and got 24psi.

Heres the weirdest: I stopped the intank pump, ran the car with just the bosch pump and got 0psi!!!

What the eff??? Im completely lost.

Any ideas?

BTW, im running a stock VT fuel rail & regulator.

Circuit: intank pump--->surge tank--->bosch 044--->fuel rail--->fuel reg--->surge tank--->fuel tank

 

[westerlybreeze]

I'd be thinking the return line too :thumbsup:

The Walbro intank feeding the surgetank as well as the Bosch 044 via return from fuel rail minus what little the injectors use and what the surgetank return flows back to main fuel tank.

25psi back pressure in the surgetank/return line is pre-pressurizing the bosch 044, giving you high idle fuel pressure :yeah:

 

[IBLOWN]

I'd be thinking the return line too :thumbsup:

The Walbro intank feeding the surgetank as well as the Bosch 044 via return from fuel rail minus what little the injectors use and what the surgetank return flows back to main fuel tank.

25psi back pressure in the surgetank/return line is pre-pressurizing the bosch 044, giving you high idle fuel pressure :yeah:

Definitely.

Tonight i'll do another test: Plumb the return line from the fuel rail straight to the fuel tank, then I'll put the return from the top of the surge tank into a bucket. Then i'll check the rail pressure.

If the rail pressure is lower, i'll permanently plumb the setup so that the rail goes straight back to the tank, then the surge tank return will also go back to the tank via another fitting i'll have to add somehow...

 

[westerlybreeze]

*** Breaking news *** A large fire has broken out in Sydney, believed to have started in a garage :rofl:

Take care dude, maybe run the hoses back in thru the gas filller?

 

[ephect]

im with westerly, return line to the maintank not surgetank.

 

[IBLOWN]

*** Breaking news *** A large fire has broken out in Sydney, believed to have started in a garage :rofl:

Take care dude, maybe run the hoses back in thru the gas filller?

Hahaha! I'll call the fire brigade while im doing it lol.