406oc.co.uk

I recently opened a thread about high fuel pressure and other symptoms like engine bogging down, since then i have still not resolved the issue so i thought i may ask again and see if there may be any help with the issue.

Symptoms.

1. Engine hesitates (as if the cylinders get flooded) then pick's up after 3500rpm.
2. When stationery and the car idles i smell petrol coming through the air vents as fuel is leaking from the main supply fuel line, just before the fuel pressure regulator. No matter how well i try and seal any leaks it will escape as if the fuel pressure is building up too high
3. Terrible mpg (average 25mpg)
4. I think this may have something to do with the problems.... There is an intermittent loud click coming from the engine bay (drivers side) but i cant pinpoint where it's coming from as it clicks once every 3-5 mins and happens quickly.

I originally thought it may be the MAP sensor and after buying one from the local motor factors was puzzled to find it has not got one the vacuum pipe that comes from the fuel pressure regulator plugs straight into the manifold.

So i was thinking that it may be the fuel pressure regulator at fault, not letting the fuel return to the tank and in turn putting up the pressure. But to my amazement i cant seem to get one from anywhere and if i find one they are very expensive. The guy at the local dealers said that the fuel pressure regulator is very rare to go and blames it on map

What would this clicking be and has anyone any tips on what to check for?
Is there any known issues that would cause such a problem ?
I was thinking about partially blocked injector, but cant see why it clears at higher rpm

ANYONE ANY IDEAS WHAT SO EVER

Thanks

Right tried today to diagnose the fuel pressure regulator today, i disconnected the fuel return and place it in a 2litre bottle and started engine. I got a steady flow about 2 litres every 30 seconds (which sounds about right). So i am confused as too why i am getting the high fuel pressure, is it unusual to get a blocked fuel return pipe anywhere between the connector in the engine bay (that i disconnected) right back to the tank?

Is there any way of knowing if the fuel return is blocked?

Can you blow through it?

Hello again steve_earwig, no i have not blown through it yet. It was easier disconnecting the fuel return line from the spring clips down the back of the engine so i cant fit my head in between the gap Must have a big head

I will disconnect the line and pull under to try and check to see if the pipe may be kinked. The fuel lines appear to be exposed through the full underside so it is possible that the previous owner/garage could of jacked up the car too close and pinched the pipe.

COME ON GUYS THERE'S GOT TO BE SOME KNOWLEDGEABLE PEOPLE OUT THERE

PLEASE HELP I NEED TO USE THIS CAR TO TAKE MY DAUGHTER TO SCHOOL AND I HAVE A FUEL LEAK ISSUE

OK So I have blown through fuel feturn and appears to be fine

What symptoms do the TPS throw up on these cars

As far as I know the fuel pressure regulator on the end of the fuel rail opens up when you 'throttle off' and returns fuel to the tank so with this in mind I would be looking at the Vacuum line from the throttle butterfly area for leaks/splits.

Sounds like it's only opening when it's being 'forced' open by excess fuel pressure.

Thanks for the reply welton I did check for vacuum leaks, but i will have a better look.

I don't know if this helps to diagnose
The car seems to respond better to partial throttle (still hesitates a little) but when i start opening the throttle more it starts to bog down as if i am flooding the engine. I still dont know if it is related to the intermittent loud tick.

I am also having more issues with the idle control valve (Constant stalling) after i cleaned it a month ago, so will have to do that again.

I have not checked the fuel pressure as i have no gauge but with the amount of leaks that keep springing up around the regulator it's obvious.

It's very confusing, If i had the funds i would get it on the diagnostics. I have already spent a fortune on this car and don't want to fork out on both diagnostics and parts.

Any help is greatly appreciated

I think I'd be inclined to just swap the regulator for a new one (I don't think they're expensive).

The ticking noise could be injector tick under the high(er) fuel pressure.

ANYONE BREAKING A 406 2.0 16v PETROL FOR SPARES

The regulator is about 80+ vat and the local motor factor don't sell them, even tying to find a car breakers with the 2.0 16v engine is impossible.
The ticking is too loud for injectors, i was thinking it may be the click from the air con compressor clutch, I could be wrong

Is there a sure way of knowing for sure it's the regulator, it seems to return the fuel ok at idle but dont know what it's doing under load

Here is the confusing bit that i forgot to mention... when idling, i think thats the only time the fuel escapes....but still have hesitation on the move.

I HATE THIS CAR TOO MAY PROBLEMS

I'm affraid we've reached my "knowledge wall" on this subject.......Where's Jasper?

Some of your descriptions are confusing.

I think the clicking is a red herring, can't be injectors if the noise is at the drivers side, injectors aren't in that place.

As for the fuel leak, have you not just got a faulty pipe? Are you trying to seal one of those moulded plastic pipes? You won't seal one of those, no matter what the pressure.A fuel leak would be there all the time, not just on idle.

The leak off pipe is just a drain, the fuel pressure has nothing to do with it, you could block it off completely, without issue.

Have you cleaned out the throttle body and the EGR valve (If yours has one)? Hesitation and stalling will relate to problems there, as well as the idle control valve.

Your lack of power may be down to an airflow meter fault.

I suggest you have a look on a dedicated diagnostic forum, such as http://www.ilexa.co.uk, or get it booked into somewhere to have it looked at.

All the things I suggested are just guesswork, It's very difficult to say what's wrong without having the car in front of you.

Welton wrote:I'm affraid we've reached my "knowledge wall" on this subject.......Where's Jasper?

I was at the gym

It's not leaking at the plastic pipe... the plastic pipe goes into an L shape adapter and then goes onto a rubber hose, the rubber hose then goes onto the fuel rail below the regulator. The fuel leak was at the L piece where the plastic bit is so i got a clip round that and tightened it and now i am getting the leak from the rubber hose that is clamped to the fuel rail. (this is the 2nd leak)

The reason i think the fuel does not leak when under load is that the fuel pressure is being reduced when driving as the pressure is used to supply the rail, so when i stop it appears the pressure is building up and leaking from the weakest point.

Or it may be that when i drive the vapors are venting else where and i cant detect it.

It's hard to know if its leaking while i drive as i can only smell it when i stop the car and leave it to idle.

I have not cleaned the throttle body yet. I am confused because i can not see an Air flow meter or sensor neither can i see a map sensor. I cant find anything saying what kind of sensors it uses. There is nothing on the airbox, the only things i see on the TB is the idle control valve and the TPS. Looking on the underside of the manifold there are no pressure sensors just various vacuum pipes (1 being the reg vacuum)

The engine is the 2.0 16V Petrol