Check your fuel pressure regulator (and pulse damper)!

Hi All,

After my recent experience with a failed fuel pulse damper diaphragm on my A610, I heartily recommend checking the fuel pressure regulator diaphragm (and fuel pulse damper diaphragm if you have one)! This applies to any fuel injected car, but particularly our GTAs and 610's.

In my case, the pulse damper diaphragm had failed. This meant that fuel was leaking out of it and being sucked into the inlet. Completely invisibly and without (apparent) symptom. I would never have checked if I'd not seen weird AFR's while on the dyno.

After 20+ years, the rubber in the diaphragms must get weak and fail. Unsurprising, really.

It's really easy to check - only takes 5 minutes!

Get a fire-extinguisher and have it close by in case of leaks and fires. Don't say I didn't warn you!

Get a small container that you can catch a bit of fuel into. In my experience, not much fuel is lost, but be careful.

Get access to the vacuum/boost pipe that's fitted to the top of the regulator and/or damper. Undo the hose clip.

Start the engine. Pull the vacuum/boost pipe off the T-piece if you have both a FPR and a damper.

After a few seconds (maybe 10-30?) if a diaphragm is faulty, fuel should start to leak out of the top of the fuel pressure regulator or the T-piece. If you have the T-piece and do get fuel from the T-piece, undo the clips on the FPR and the damper and pull off their hoses to isolate which is faulty.

Go carefully!

Andrew

[phildini]

Good to know Andrew, I will check my GTA, thanks

Are you able to post a picture, or a link to the parts book, .....just so we are sure we are all checking the right same thing?
Thanks too.

As I posted a while back they will all need changing as the rubber is not ethanol resistance the new petrol just turns the rubber to jelly, any rubber in contact with the new fuel is subject to this problem, ie high pressure fuel lines change them all it is not worth the risk.

Diaphragms in the standard Renault fuel reg / damper are tin unless I'm much mistaken! Not rubber.

To be honest I have never smashed one up to find out but any thing that is 20+ years old should be changed, just look at the water pipes for example so the fuel side should be higher on the list for replacement.

[stephendell]

To be honest I have never smashed one up to find out but any thing that is 20+ years old should be changed, just look at the water pipes for example so the fuel side should be higher on the list for replacement.

From recent TV looks like the fuel system on an Alpine only has a life span of approx. 20 minutes so definitely worth checking lol

Problem is that tin is very easily corroded in contact with water (just look at the colour of the streams in Cornwall)

Mine perforated years ago after the local petrol station got water in their tanks. Doesn't take much, so yes it's a good idea safety wise to replace if in doubt.

Get a fire-extinguisher and have it close by in case of leaks and fires. Don't say I didn't warn you!

A safer way of checking is with two short lengths of pipe and a glass of water. One pipe to one side of the diaphragm, and the other pipe to the other side of the diaphragm............... put one pipe into the glass of water, and blow into the the other pipe and look for bubbles in the glass of water.