VN fuel pressure regulator

[delcowizzid]

following on from abbas post is the fuel inlet into the rail with no reg and going out via the fuel pressure reg not the other way round like has been done many times

 

[85commolux]

I checked the fuel pressure and got a reading of 40 Psi with ignition on & 35 Psi @ idle, I pulled the vacuum line off the regulator with it running and it jumped about 10 Psi. It also still holds pressure after shut down.

 

[85commolux]

Ok. I can now hear a hissing noise in the fuel line around the rail area when the engine dies, I am wondering if it could be leaking injectors? Also a couple of times the fuel pressure dropped very quickly to zero.

 

[Not_An_Abba_Fan]

A leaking injector would make it hard to start, but it will still run.

40 psi is more than enough for it to run.

Have you tried running it with the regulator just disconnected? Don't clamp off the line, just disconnect the vacuum hose and block it off where it goes back to the elbow.

 

[85commolux]

I pulled the hose off the regulator before while I was testing the pressure and it rose 10
psi, which is what it is supposed to do apparantly

 

[Cheap6]

10 psi is spot on - that's your 22"Hg manifold vacuum (which is actually 10.8psi - near enough).

35 psi/243kPa at idle is also about right. A bit less than 250 kPa but within what I would expect with gauge error and differences between individual engines.

You should've seen 46 psi/320 kPa with the fuel pump running, engine off. It will be a bit lower with the pump off immediately after ignition (pump) on, so the 40 psi is OK with that happening.

Maybe go back to the engine management side of things. You've tried disconnecting the MAP and TPS. What happens if you try the same with the CTS and MAT?

The CTS should have resistance of about 2000 ohms at 25C, 190 ohms at 100C. The CTS signal wire is C10, yellow, at the ECM - something around 1.3V or a bit less between that and D2 (earth) would be right, engine hot.

The MAT should be about 3000 ohms at 25C, ~500 ohms at 60C. ~1-2V across C12 and A11 at ECM, depending on temp. in the inlet manifold.

The MAP voltage drops with vac. applied so that sounds OK if the voltage is seen at the ECM. Does the TPS signal voltage - C13 at the ECM, blue wire, D2 is the earth for that too - vary with throttle position?

Do you have a spare ECM or better yet, access to a running VN, VP, JD unleaded or JE Camira, LD Astra/N13 Pulsar that you can try your ECM in?

 

[FXST01]

I'm thinking the injectors may need a decent clean, not the cleaner in the fuel type clean but a proper specialist type clean.

Failing that I would undo the four bolts and lift the injectors and fuel rail clear of their little holes, twist them so they face out and prime the fuel pump, see if any are leaking and then turn the car over quickly and make note if they are all injecting and what type of pattern they do. Take the proper precautions before doing this type of thing.

 

[delcowizzid]

yeah ide be carefull for sure one spark and all that nicely vapourised fuel goes up fast LOL.

 

[85commolux]

Well, this afternoon I decided to try my old ECU which is buggered (showing a 51 code) and the engine runs, albeit rough as guts. Unplugged it and plugged in the other one and again no go.

 

[delcowizzid]

error 51 will make it run solely off the backup resistors maybe cheack the other ecu and make sure it has a memcal in it and that it suits 6 cylinder maybe swap the memcal from the code 51 ecu into it and see how it goes post up the number off the silver sticker on the chip in the memcal ill tell you if its a v6 tune or not