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Fuel Not Geting Into Cylinders

30ed32

By 30ed32,
in Engines & Forced Induction

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30ed32 Enthusiast

30ed32

Posted
Posted (edited)

Hi there, so just a little detail about the engine: it's a newly build rb30det with 25 head, 440cc subaru sti version 6 injectors, ecu I don't think is that important to mention as it will be getting chipped, but both the rb25 ecu and rb20 ecu (to be chipped) have been tried.

Anyway the problem is that fuel isn't getting into the cylinder and it's a mystery to me for a few reasons:

1. The fuel pump is working as you can hear it priming and if you take the hose off the fuel rail it squirts out.

2. The injectors are getting power, I've checked for a constant 12v and when cranking it pulses as it should.

3. I have listened to all 6 injectors and they are all pulsing when cranking.

4. I have put direct voltage on the injectors and when I do, they fill up the cylinder pretty quickly.

5. The hoses aren't the wrong way around to the fuel rail and I got an adjustable fuel pressure regulator with a gauge, pretty much just to monitor the pressure. It's around 3.8bar when it primes and when cranking drops to around 1.8-2bar.

After cranking for a while you would expect it to be a bit wet on top of the piston or maybe have the smell of petrol, but there's nothing. I'm really out of ideas on this one, so if anyone has any advice it would be much appreciated.

Thanks in advance

Edited by 30ed32
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blind_elk Grand Master

blind_elk

Posted
Posted

3.8bar at IGN ON is a bit high. 2bar at start is too low.

Specs are:

3.0 @ IGN ON

2.5 @ idle

3.0 @ idle with vac hose disconnected

Are you sure the pump is working while the engine is cranking?

30ed32 Enthusiast

30ed32

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Posted

Well it does drop drastically while cranking, the longer you go the lower and lower the pressure gets without anything coming out the injectors would indicate that it's not working, but I would still expect some fuel to come out. Also as soon as cranking stops it shoots back up to 3.8 and sounds like it's just constantly priming. Even leaving it for 5 mins with ign on the pump just keeps going, but holds a constant pressure. So I don't know, possibly the power source or ecu trigger. Strange that it would stop working while cranking though, next thing to check is if the pump is getting power while cranking I suppose. Unless anyone else has any better ideas.

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