Pressure regulator faulty?

[whodunit]

Hi,

Hoping for some insight...

Have just reconnected my new fuel lines after carrying out some work on my Grif 500. I switched on the ignition with the hoses disconnected just to run a little fuel through to flush any particles out (this also helped me by confirming which the send and receive pipes are). Anyway, connected up the fuel "supply" hose to the fuel rail and thought it might be a good idea to flush fuel through the rail and into a bucket before connecting the return.

I can hear the fuel pump running but no fuel is returning. What I expected to see was the fuel rail charging with fuel and then excess fuel coming past the regulator and returning to the tank? Is this correct and does the fact that fuel isn't flowing past the regulator indicate that it is faulty?

Just as an extra headache. I noticed one of the fuel injectors leaking where it connects to the fuel rail. Could this be caused by excessive pressure in the fuel rail (i.e. nothing is returning past the regulator)? I have had the fuel rail off and it is possible that I have disturbed the "O" ring where the injector meets the the fuel rail but didn't want to strip it all down again if it was a pressure problem...

Thanks for any help / advice you can give!

[blitzracing]

You dont say where you where testing the fuel return? Id put a short pipe onto the regulator output and try from there. I certainly had the same problem on a Ginetta, where the return pipe got crushed, and it pushed one of the injectors out of the fuel rail and filled the center of the engine V with fuel! Ive not come across a stuck regulator (yet anyway), just ones that leak, due to dirt being trapped in the valve.

[spend]

Did you hot wire the fuel pump, it will only briefly pulse on the key unless the engine is running....

[whodunit]

Hi,

Just to answer your Q's:

I connected up the supply fuel hose but left the return hose (coming back from the regulator) unconnected so that I could run it into a bucket.

Spend, yes, the pump ran exactly as to described. It ran for a few seconds and stopped. When flushing through the fuel supply hose, I turned the ginition on and off a few times to get fuel through. Once I connected the supply hose, I was holding the return hose from the regulator in a bucket and used the same technique as mentioned above to run some fuel through the rail, via the regulator and into a bucket.

Unfortinately, no fuel returned (even though I had already proven the supply line) and the injector last pon the fuel rail (just before the regulator) started to leak where it connects to the fuel rail.

BTW, there is a reasonable chance that the regulator is beggared as I am finishing rebuilding this area and the engine had previously suffered a small engine fire and so presumably the regulator has been subjected to some heat.

I didn't want to replace the regulator without testing it first and hence was running fuel around the system to test it. I suppose the key questions I have got if you can help are:

1) Should I have been seeing fuel return from the regulator and into the bucket?

2) Since nothing was returning and I am pretty sure the fuel rail was pressurised, could this be the cuse of the injector leaking?

Cheers and happy Christmas too!

[spend]

Yes, try a new regulator.

Could be the cause of your leak, but I'd still put in new o-ring seals and make sure the rail legs are clamping it OK (fuel peeing out into engine or over manifolds is not a chance you want to take).

[blitzracing]

Before you spend your hard earned cash, you can test the regulator on an compressor / airline. If you let the pressure build on the inlet side it will be quite obvious when it opens at 37 or so PSI. Dont take much notice if it continues to let air past as the pressure drops below 37 psi, working ones do this, I guess air is so much thinner than petrol it does not shut off effectively once its opened.

[spend]

After an engine fire (however small) I wouldn't take a risk with the TVR and just renew all the bits with new, Binettas I wouldn't worry about

[whodunit]

Hi guys,

Thanks for the advice. I think I will test the regulator (for experience) but no doubt will end up replacing it.

Spend, regarding the "fuel rail legs", I'm not sure what you mean. From memory, to reassemble, I pushed the fuel rail onto the injectors and then there was a small clamp to hold it in place. Are the legs the bracket part of the fuel rail that hold it down in place? If so, will double check, but pretty sure the fuel rail is secured nice and snug down onto the injector.

Good point, I really should replace the "O" rings to be sure. BTW, when I removed the fuel rail initially, I had removed the plenum and inlet manifold to allow it to lift off of the injectors. Is this the best way to do it? Also, when I refitted the inlet manifold and plenum I just used a thin layer of instant gasket to seal them? Is this the best way? I couldn't see a gasket during the removal but could see a slight residue of what I assumed was instant gasket....

Cheers!

[spend]

Yes there are 4 'bendy' legs brazed to the fuel rail which bolt down - its fairly easy to bend them out of shape removing & refitting the rail..

I wouldn't trust any of those seals, rail, injector or regulator itself when they have been near fire. Personally I'd bin them all and renew whatever they looked like, and I'm not even particularly paranoid about the fuel pipe's like others are I'd certainly rather have fuel leaking round the bellhousing rather than the fuel rail IYSWIM.

[macdeb]

whodunit said:

Hi guys,

Thanks for the advice. I think I will test the regulator (for experience) but no doubt will end up replacing it.

If you get a standard regulator, then fine. But, if you go for an aftermarket regulator be careful which one you go for. There is a common one around that I would NEVER EVER go near again. Fluctuating pressure, noise and piss poor aftersale service Mail me if you wish to find out what NOT to buy.

Edited by macdeb on Monday 27th December 12:25

[SILICONE KID]

You need a Malpassi adjustable FSE 1:1 linear not rising rate fuel regualator ..demon Tweaks sell them..mine is fitted on the left hand side.
http://www.demon-tweeks.co.uk/Motorsport/Fuel_Syst...

Edited by SILICONE KID on Monday 27th December 23:28

[blitzracing]

I hope Daz you have a fuel pressure gauge floating around some where to add to it, otherwise guesswork is a dangerous game .

[SILICONE KID]

Yes set up with the Megasquirt, i think its set at 37psi with vacuum pipe off.I don`t like to leave the guage on the regulator.

[whodunit]

Hi guys,

Thanks for your comments above. Just to let you know, tested the regulator using air pressure and it didn't let anything past even at 40+psi, so regulator is defo suspect

I have seen mixed messanges regarding whether to use an adjustable pressure regulator or not and so was chicken and bought a standard one... Haven't received it yet but hopefully this will work and get me back on track. Also ordered some new "O" rings for the injectors.

Cheers!

[macdeb]

whodunit said:

Hi guys,

Thanks for your comments above. Just to let you know, tested the regulator using air pressure and it didn't let anything past even at 40+psi, so regulator is defo suspect

I have seen mixed messanges regarding whether to use an adjustable pressure regulator or not and so was chicken and bought a standard one... Haven't received it yet but hopefully this will work and get me back on track. Also ordered some new "O" rings for the injectors.

Cheers!

think you've done the right thing. My aftermarket fse pile of crap ended up costing me a few bob.