Testing For A Leaking Fuel Injector

[WogsRus]

So in my quest to find my cold start issues with the car, as described here

http://www.skylinesaustralia.com/forums/in...howtopic=160180

I did the following test.

I put a fuel pressure gauge in and tested the fuel leakage and so forth.

Basically if left alone the fuel pressure eventually bleeds off to 14.5 psi, over the night, which is to spec, I need to find the correct page again to give details. So then I pressurized the system and blocked off supply and return. The reading was 40psi, after and hour still 40 psi, after 2 hours 39 psi, but this was at night 11:30pm to be exact. Then over night the pressure dropped of to 20psi or so.

However I was told that the pressure loss is worked out over 30 minutes, so if there is no substantial pressure loss the system is ok. THIS IS TAKEN FORM A MECHANIC THAT WORKS ON FUEL DELIVERY SYSTEMS. CAN SOMONE CONFIRM.

Does this mean the injectros are leaking badly? or something?

[MBS206]

If it's worked out over a half an hour period, and from one point to the next, which is an hour apart, the reading is fine, since 40PSi at A is equal to 40PSi at B.

That would be my thoughts.

Wouldn't it work for you to unplug the injectors out of the motor, pull the whole fuel rail out, have injectors plugged into the fuel rail and into the loom, sitting it over a bucket, prime the fuel system up, and just leave them to sit and see if you have petrol in the bucket at the end? (I'd also put a rag over the top of the injectors and bucket to help avoid the fuel from evaporating.

[WogsRus]

yeah you could do that too, i am trying to avoing pulling everything out.

So does anyone know the correct figures for the fuel injectors.

[MBS206]

I'd be pulling them anyway myself.

Seriously, if it's leaking it needs to come out basically anyway. So pull em, test em, throw in new set if need be, if not, send them away for a clean.

[WogsRus]

But that is the thing, if i pull them out, i still need to get new seals and stuff, this way i can just test them.

[Cubes]

A mate of mine used to have a spare manifold where he would sit it on top of a piece of paper.

The reason for the manifold is that the injectors will not sit in the rail when pressurised, they require the manifold to be held in.

He ran a long piece of hose from the car to the manifold/fuel rail/injectors sitting on the ground, pressurised it all up and then let it sit overnight. Check the paper in the morning and its obvious if any fuel has dribbled out the injectors.

His would hold pressure fine as yours do but overnight we could see fuel had leaked from the injector. Unsure if this is normal, we assumed not.