Fuel Injection Problem

[r33cruiser]

hi guys. after recently sticking in a forward facing plenum my car does not inject fuel.

when on, the pump still wirrs up, fuel fills the rail, and it doesnt seem to be going through the injectors. fuel remains at 60psi ish, proving that fuel is in the rail....but thats as far as it goes. have checked the circuit, all is fine. i have also checked the ignition, aac valve, afm and it is all fine.

the car still cranks, and it really wants to crank over, but it only partially catches and doesn't idle.....IT IS SOO CLOSE. so far we have definitely narrowed it to the fuel injection system.

i just wanted to get your opinions before i went to a mechanic/electrician. i am getting pretty pissed because it has been off the road for a month. at the same time i also installed a gt3540 with .82rear, custom h/m manifold and tial wastegate. and all the plumbing for that is perfect.

Edited January 27, 2008 by r33cruiser

[paulr33]

does it start any better if you hold the throttle a little open?

checked all the common fuses etc?

do you hear spark properly? screwdriver on the head & listen to it

have you changed or modified the TPS in any way?

what ecu? what diags does it have?

[Adriano]

Try spraying some aerostart in the manifold and see if that makes it start, if so the injectors aren't firing. Also pull out a spark plug and see if its wet

[GeeTR]

Nice turbo choice

60psi massive, ~43psi is base pressure btw.

Usual checks, are your plugs wet? if so, are you get'n spark? Checked ECU for codes? Tried disconnecting AFM?

Start from the bottom and work your way up. If you haul it to a shop and let em know you've done a full turbo swap in your garage, they will charge you through your ring. That said, if the above is all you've tried.. maybe leave it to somone else truth

EDIT: dammmmmit i need to learn to refreash a window b4 posting

Edited January 27, 2008 by GeeTR

[r33cruiser]

lol respect.

stock management....emu hasnt arrived.

yea..when fuel is let into the cylinders when the injectors are out, the engine starts for a few sec. but atm it is starved of fuel..but injectors are fine, have a circuit and are clean.

it cant be an injector fault. what are the odds of all six going?

pressure is high because the fuel isnt going anywhere, this is my problem

but i will try disconnecting the afm.

+ i put in my other injectors and they arent firing ????

so i think its electrical but i cant find the problem.. but it is getting power and everything.

Edited January 27, 2008 by r33cruiser

[zebra]

You haven't got a rag or something still stuck in a cooler pipe have you?

Seen that before.

[James_03]

remove the rail and put a large rag down over the motor, then remove the CAS, turn the ignition on and spin the cas. You should be able to see each injector firing. It will be just like mist but check the spray pattern on each injector, and more importantly that they are all working.

If its ok put it back in. Check that plennum has no leaks becuase they can be pretty nasty.

[Adriano]

I dont know if i would recommend this, as the fuel pressure could easily blow the injectors out, potentially spilling litres of fuel under pressure. If you leave the injectors in, and unplug the igniter, pull the cas out and spin it you should hear the injectors firing, or test them with a noid light. Are you sure all the earths are hooked back up, there are two from the loom to the inlet manifold. Also check for power between one of the injector wires on each plug and the manifold. One wire on each injector should have battery voltage, the other is a swithed earth. PS are they the same injetors that came out of the motor before the maniflod change. Could there be a possibility that the fuel lines have been swapped around on the fuel rail(seen this a few times)

Edited January 27, 2008 by Adriano

[Adriano]

On further thought, i bet its the fuel lines the wrong way around, it s the only reason the fuel pressure would go up, not because the injectors aren't firing. It does have a stock regulator doesnt it?

[James_03]

I dont know if i would recommend this, as the fuel pressure could easily blow the injectors out, potentially spilling litres of fuel under pressure.

Seeing has its an r33 with side feed injectors, you should be safe to do this. The injectors are held in firmly by the base of the rail, and also by the top 2 screws above each injector. The bolts holding the rail simply hold it in against the top plennum o-rings. I would not recommend this with an rb26 but as that is likely to occur.

Edited January 27, 2008 by James_03

[r33cruiser]

thanks for your replies.

the fuel feed line is coming from the fuel filter...so its the right way around.

everything has a circuit and a good earth. and yup adriano injectors are getting 1 12v current and 1 6v current.

i will check the cas, however it doesnt appear to be ignition...the injectors arent opening.

i wil have a look make sure there are no rags in there too.

and yea STOCK FPR.

Edited January 28, 2008 by r33cruiser

[RB30-POWER]

go to bursons/repco and get a $10 noid light to check for injection pulse.

[r33cruiser]

thanks mate,...just bought one.

pulse is fine, ignition is fine. the fuel seems to stop at the fpr. i even chucked in my nismo adj fpr, and it only flows fuel if the screw it almost wound out, at very low psi.

now that flows enough fuel to start it...but doesnt keep running.

it is almost as if the fpr is blocked. but blew it with a compressor and it is clear, but doesnt flow..

any ideas, appears to be the fpr.

both stock and nismo dont flow enough fuel

[Adriano]

Not trying to sound rude, but the fuel is flowing through the fuel filter, then rail, then through the pressure reg.

[STATUS]

just making 100% sure that the fuel line from the filter is going to the fuel inlet (not the line connected to the fpr) and the return line to tank is connected to fpr.... your symptoms still sound like lines are mixed up.

[r33cruiser]

yea mate, no need to apologise. i dont care. speak your mind

yea we checked all that, even tested it without fpr on,.

fuel pumps out fine

your absolutely right uras. it is all hooked up fine

Edited January 28, 2008 by r33cruiser

[RB30-POWER]

are these the same injectors you were running before plenum upgrade or upgraded injectors?

if they were ultrasonically cleaned and left to sit for a while (days-weeks before installation), the pintles tend to stick and do not open, been down this path myself a couple of times, now i don't get injectors cleaned until the day i plan to start the car

sorry to explain the basics again!

but,

1) remove both fuel hoses from the rail/reg, face both into a bucket, get mate to prime pump (ignition on) fuel should piss out for 5 secs as the pump primes, take note of what hose fuel comes out of!

2) now connect that hose that fuel comes out of onto the inlet to the rail, that is the opposite end of the fuel pressure reg.

3) now get mate to prime pump again (might take a few primes to fill rail, crank it if you prefer) does fuel come out of the fuel pressure reg exit pipe?

4a) if yes, hook the other efi hose back up (return to tank), you know for fact you have fuel.

4b) if fuel does not come out of the reg, the reg is stuck/jammed closed or rail blocked (both highly unlikely)

now for spark,

1) remove the coil pack cover, remove no 1 ignition coil (easiest) remove spark plug from engine,

2) push spark plug back into ignition coil, hold the coil pack and make sure the spark plug body is touching a good earth point on engine

3) get your mate to crank engine and check for spark jumping across the electrode tips as engine cranks.

4) once you have confirmed that, remove all 6 spark plugs and make sure they are clean, they may be fouled (look black and wet) from all the stuffing around and they will not fire. its critical they are clean, get some petrol and sand paper and compressed air, clean them good.

[Adriano]

4(b)could also be a stuffed fuel pump, if it cant generate enough pressure to overcome the FPR

[r33cruiser]

ok. think me and my mates found the problem. we used the noid light=working fine.

looked at spark=worked fine.

we lowered the fuel pressure to minimal...just to start it,,,and it did start.

however on the boost gauge, we werent reading any vacuum. it was on 0.

we then noticed a break in the seal of the TB.

so no vacuum would cause the fpr not to open, hence no fuel getting in with the right pressure., atleast thats what we think.

so we will fix up the TB seal later and see how we go.

thanks for the advice