S6 timing

[HMS-S6]

Also with regard to the fuel smell, it's only with the car running.

[HMS-S6]

I am. I'm going to do the filter thing Dave said anyway and then I'm going to run a line into the car somehow so I can have it in the car with me. Not terribly 'health and safety' I know but hey ho!

[diesel des]

Is the tank breather system ok. If its blocked or not working properly a vacuum could occur in the tank which could cause the inlet of the pump to restrict. I would do what Dimitri said and drive around with a fuel pressure gauge in the car and note what happens when you have issues. You should have 4 bar above intake pressure. So at 1 bar boost thats 5 bar. Good luck.

[driftin jo]

Not sure. Might be related to how high the fuel level is in your tank. When it high, i.e. filled to the second click, fuel is in the No.2 pipe above the fuel tank. Therefore, there could be a leak at the connection between Item 5 Hose and items 1 (tank) and 2 (filler pipe).

When the fuel level in the tank is high, the pressure head on the fuel pump inlet is higher, making it easier for the pump to increase the pressure to that required at the fuel rail (4Bar plus boost pressure). When the fuel level is lower, there is less pressure head on the fuel pump inlet, making it more difficult for the pump to increase the pressure to the required levels. As a result, it is possible that your lack of fuel is the result of a weak pump that is aided by higher fuel levels and hindered by lower fuel levels.

Bottomline: I would change the fuel pump using the DIY that I have posted at least once in this saga, er, thread.

1 meter head is 0.098 bar ! As the tank is ~ 250mm deep, a full tank would give the pump
0.0245 bar (0.36 psi) pressure help from a nearly empty tank.
I fail to see how this is going to make any difference.

[UrS4boy]

C4 UrS Fuel Lines Near the Filter

Hmmmm. The pump is under a year old and a genuine part! It'll whip it out AGAIN! Think I should Velcro my car together. Hahaha

Can't remember what the fuel filter status is. I would disconnect the feed line into the filter, put a hose on the open end of the line, run the hose into a gas can and then energize the fuel pump using the No. 17 fuse holder (as I have described before). Maybe run it for 30 seconds or a minute (fill the can). The shut off the fuel pump. THEN replace the fuel filter with a new one. There is still a chance that the fuel pump is fine but the filter is clogged. And please don't say it's new. If you didn't blow the lines out as described above when you installed the fuel filter, a new one could now be clogged too.

C4 UrS Fuel Lines near the fuel filter: http://forums.quattroworld.com/s4s6/msgs/287584.phtml

[HMS-S6]

Just check fuel pressure, any issues with the fuel system will be highlighted by the fuel pressure check.
You need to eyeball the gauge while it's hesitating and see what is going on there.

144 load seems low to me on WOT.

Righto. I'll make that my next check!

[prj]

Just check fuel pressure, any issues with the fuel system will be highlighted by the fuel pressure check.
You need to eyeball the gauge while it's hesitating and see what is going on there.

144 load seems low to me on WOT.

[HMS-S6]

Hmmmm. The pump is under a year old and a genuine part! It'll whip it out AGAIN! Think I should Velcro my car together. Hahaha

[UrS4boy]

Dave, any ideas on an intermittent STRONG smell of fuel around that wheel?

Not sure. Might be related to how high the fuel level is in your tank. When it high, i.e. filled to the second click, fuel is in the No.2 pipe above the fuel tank. Therefore, there could be a leak at the connection between Item 5 Hose and items 1 (tank) and 2 (filler pipe).

When the fuel level in the tank is high, the pressure head on the fuel pump inlet is higher, making it easier for the pump to increase the pressure to that required at the fuel rail (4Bar plus boost pressure). When the fuel level is lower, there is less pressure head on the fuel pump inlet, making it more difficult for the pump to increase the pressure to the required levels. As a result, it is possible that your lack of fuel is the result of a weak pump that is aided by higher fuel levels and hindered by lower fuel levels.

Bottomline: I would change the fuel pump using the DIY that I have posted at least once in this saga, er, thread.

[HMS-S6]

Ok I'll pop the gauge back on as soon as I can. The load value in group 000 with the stock ECU is now 144 at 3,600 at wot. Is that enough Dmitri?
I think it's struggling to run correct even at idle, showing 15:1 most of the time, sometimes higher.
Soon as you can fit me in Dmitri I'll hapily pay you whatever for fixing this damn car!

[prj]

Don't drive steadily. Just drive like it like you stole it. If it senses a "grandpa" driving, you will get "grandpa" responses.

This is nonsense, there is no adaptation in the ECU to note of, the only one that stores any kind of values is the ISV and idle fuel trim, which is not used on WOT.
There is no need to reset anything or pull any fuses, it makes no difference.
It's a machine, not a living thing all this "ECU reset" stuff is just hogwash.

If mixture shows lean, and it goes like a switch then there must be a misfire going on. Either that, or the fuel pressure drops.
I know you checked it with a gauge, but maybe worth checking again if the problem is worse? Like checking what the gauge shows at the time the problem appears?

Remember, I had similar problems with my car and it turned out to be the fuel pump in the end.

[HMS-S6]

Dave, any ideas on an intermittent STRONG smell of fuel around that wheel?

[HMS-S6]

Ok Dave! I don't need telling twice to do that! Haha. I have to nip out in a couple hours. I'll do just that!

[UrS4boy]

Above the C4 UrS ECU fuse panel and related issues

Once the ecu is refitted is there a particular way to allow it to adapt or just drive it steadily?

Don't drive steadily. Just drive like it like you stole it. If it senses a "grandpa" driving, you will get "grandpa" responses.

You can reset the C4 UrS ECU by pulling the 5 amp ECU fuse in the red holder above the ECU, with the ignition OFF.

http://forums.quattroworld.com/s4s6/msgs/137287.phtml

[HMS-S6]

It may just be pure coincidence but while it was pulling correctly at the weekend I had a smell of fuel around the right rear wheel strong enough to make me pull over and check it wasn't pouring out!! Since it's run crap I've had no smell at all. Like I say this may be completely unrelated!