Nothing coming out of injectors?

[FourtyKid]

I just replaced the O-rings on my SR's injectors. I installed them and everything went perfect. But before putting the fuel rail back on, I figured I'd check to make sure everything was working correctly. So I had someone turn the key to prime the fuel system and there's nothing coming out of the injectors. I've got 43psi of fuel pressure going to the rail and I can hear the fuel going through the rail and back through the FPR to the return line. Nothing is going into the injectors. Can someone help with this?

TL;DR: Have fuel going through fuel rail but nothing coming out of injectors.

[DJ-of-E]

this may be a stupid statement, but have to check to make sure fuel injectors are electrically connected?

[whitey240]

spin the cas

[ultimateirving]

^^ what he said the injectors wont fire unless you spin the cas or bump the ignition.. They arent going to be always on, that would flood ur shit

[FourtyKid]

Originally Posted by DJ-of-E

this may be a stupid statement, but have to check to make sure fuel injectors are electrically connected?

Well I just tried flipping the polarity on one of them and it didn't change anything. Also had a multimeter on the connections while priming and there was zero volts. I'll try turning the CAS.

[DJ-of-E]

Originally Posted by ultimateirving

^^ what he said the injectors wont fire unless you spin the cas or bump the ignition.. They arent going to be always on, that would flood ur shit

That's what I was thinking until...

I can hear the fuel going through the rail and back through the FPR to the return line.

You electrical lines might be the case if you do reverse the polarity. Normally from here, I tried to close other possibilities.

I would find another running SR 240sx or take the fuel injector to the shop to test if fuel injectors are spraying. If no, they're no good. If they are, then you have an electrical issue.

This is why I like OBDII system, so much easier to diagnose. These OBD1 or custom ECU engines are pain in the butt.

[zerodameaon]

Try turning over the car if spinning the cas does not work. As everyone else said they would not just spray a shot of fuel into the cyl when you prime the fuel pump, if they did you would have issues unlike now where it sounds like everything is functioning properly.

[FourtyKid]

Originally Posted by zerodameaon

Try turning over the car if spinning the cas does not work. As everyone else said they would not just spray a shot of fuel into the cyl when you prime the fuel pump, if they did you would have issues unlike now where it sounds like everything is functioning properly.

Do I need spark plugs installed to try this? I have yet to install my new ones and my current ones are shot. I'm getting a gapper tool later to install them but until then will turning it over without them work? I know the car won't fire without them, but it still should inject gas right?

[whitey240]

no just spin the cas with and you will hear them click. Don't put your finger under the injector nozzle either.

[FourtyKid]

Alright here's a video from my GoPro. You'll want to turn it up.



So I can hear clicking but they didn't spray...? This is with the key to ON.

[zerodameaon]

Watching your fuel gauge something is happening but I can't listen because I am at work. And no spark is a good thing in the case I gave, if you have any fuel shoot into the intake it may backfire with the injectors and rail out.

[cotbu]

If the ecu has power with the koeo and the ignitor and cas are connected? Make sure you have 12v or battery voltage to the injectors, they don't care which side has the voltage, the ecu via spinning the cas will trigger the injectors. If not usually the brown plug if not then gray plug by the front passenger side maybe where the issue lies. On the east coast this is a common problem I fix alot

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[FourtyKid]

Originally Posted by cotbu

If the ecu has power with the koeo and the ignitor and cas are connected? Make sure you have 12v or battery voltage to the injectors, they don't care which side has the voltage, the ecu via spinning the cas will trigger the injectors. If not usually the brown plug if not then gray plug by the front passenger side maybe where the issue lies. On the east coast this is a common problem I fix alot

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I had a multimeter on the injector when it was priming (don't know if that was the right time to test it) and I got zero volts. Will it only show 12v while they're spraying or all the time?

[cotbu]

Don't jump a head of yourself, check to see if they have 12v with the key on. If not you have to fix that, ok.
With the key off they should have 12v if that helps.

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[FourtyKid]

Originally Posted by cotbu

Don't jump a head of yourself, check to see if they have 12v with the key on. If not you have to fix that, ok.
With the key off they should have 12v if that helps.

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When the key is on, they have 0v.

[cotbu]

You're checking both sides right to rule out error, With the key on they should have battery voltage, on one side, the other side is controlled by the ecu. Check the brown plug by the passenger front fender probe that for 12v the run a continuity test from that to the injectors, if you don't have 12v at that plug you'll have to wait for me to get home or see if another member will chime in

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[FourtyKid]

Originally Posted by cotbu

You're checking both sides right to rule out error, With the key on they should have battery voltage, on one side, the other side is controlled by the ecu. Check the brown plug by the passenger front fender probe that for 12v the run a continuity test from that to the injectors, if you don't have 12v at that plug you'll have to wait for me to get home or see if another member will chime in

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By "checking both sides" you mean switching the multimeter wires around on the positive/negative right? If so, yes. I'll look for a brown plug.

[godsmack]

Originally Posted by FourtyKid

By "checking both sides" you mean switching the multimeter wires around on the positive/negative right? If so, yes. I'll look for a brown plug.

No he's saying to check all of the wires for the injector. 1 should have power and the other should not. If you don't have power at any then check the power wires on those 2 plugs by where the battery is.

[FourtyKid]

Originally Posted by godsmack

No he's saying to check all of the wires for the injector. 1 should have power and the other should not. If you don't have power at any then check the power wires on those 2 plugs by where the battery is.

Ok I am getting twelve volts now, so what's next?

[cotbu]

If you have 12v at the injectors now, turn the key on and spin the cas, the injectors should fire!

Nothing coming out of injectors?

[FourtyKid]

Originally Posted by cotbu

If you have 12v at the injectors now, turn the key on and spin the cas, the injectors should fire!

Well I'm not sure if I fixed anything or what, I switched multimeters because I realized the one I was using wasn't working at all, so I tried another and it's showing 12v with the new multimeter. I have everything back together now though. Should I put the fuel rail back on and actually try to start it? Maybe they'll pump then?

[cotbu]

if it still off just go ahead and check them, you'll know for sure if they're working. if you bolt it back up before you check and it doesn't start you have to check again for both spark and fuel. You can do both with out starting the car.

[FourtyKid]

Originally Posted by cotbu

if it still off just go ahead and check them, you'll know for sure if they're working. if you bolt it back up before you check and it doesn't start you have to check again for both spark and fuel. You can do both with out starting the car.

So since my valve cover is back on, I tried turning the car over. Fuel rail is still out so I just put a towel under them so I could see if they would spray. Nothing. But they are getting power.

[cotbu]

The ecu would be my next guess if the spark plugs fired when you turned the cas,/engine over. See how diagnostics work, if the spark plugs fired I would check the ecu, if not it could be anything in between

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[FourtyKid]

Originally Posted by cotbu

The ecu would be my next guess if the spark plugs fired when you turned the cas,/engine over. See how diagnostics work, if the spark plugs fired I would check the ecu, if not it could be anything in between

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Well I checked the codes from the ECU and I've Cam Position Sensor and MAF codes. So I'll have to take the valve cover off again and reset the CAS. I'll figure the MAF out later.

[cotbu]

You shouldn't have to take the valve cover off to set the cas.
Set engine to TDC and prepare the cas for installation and get a timing light. re seat all the sensor plugs and clear codes.
Did the injectors click when you....well you didn't spin the cas by hand so you could hear if the injectors clicked or even if the coilpacks clicked. so before you set the cas i would run that check. if they click and no fuel comes out, check your fuel lines. fuel flows like this (tank--pump--filter--rail--regulator--tank) Take out your ecu and let a friend try it in their car, to rule out ecu. if you put their ecu in your car and the problem lies in the wiring? You could damage their ecu.

[FourtyKid]

Originally Posted by cotbu

You shouldn't have to take the valve cover off to set the cas.
Set engine to TDC and prepare the cas for installation and get a timing light. re seat all the sensor plugs and clear codes.
Did the injectors click when you....well you didn't spin the cas by hand so you could hear if the injectors clicked or even if the coilpacks clicked. so before you set the cas i would run that check. if they click and no fuel comes out, check your fuel lines. fuel flows like this (tank--pump--filter--rail--regulator--tank) Take out your ecu and let a friend try it in their car, to rule out ecu. if you put their ecu in your car and the problem lies in the wiring? You could damage their ecu.

I did turn the CAS, I posted a video of it too. They did click and nothing came out. I'm pretty sure my fuel lines are right but I can post some pictures to confirm. I literally don't know another person with a 240sx so that last part isn't exactly feasible.

[cotbu]

My bad, I see in that video your fp gauge moves everytime the injectors fire, can't remember if that's normal, check the lines

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[FourtyKid]

You'll have to excuse my crappy video. It's 12:30am here.

Also, here are some pictures to hopefully help clarify it.

[cotbu]

Im not totally sure, you have the lines correct, it looks right but if the lines are wrong at the pump then what looks correct is wrong.. disconnect the fuel feed line, the one running to the rail via the fuel gauge put it in.a bottle if your lines are correct then fuel will flow in the bottle if you are not sure, put both lines in the bottle. Prime the pump koeo.
If you are doing these test correctly you are probable gonna have to start spending money.

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