Fuel leak under acceleration

[skendrick]

Can anyone help?

Where is the best place to start looking for a fuel leak under acceleration?
When driving sensibly I don't have any problems but when I start accelerating hard I gets a smell of fuel through my open window (please don't say shut the window). If I accelerate hard from low revs say 2500rpm, then the EMS cuts in around 4000rpm and the car kangaroos down the road for about 30secs until the problem rectifies itself.

Any suggestions?

Steve

 

[Fen]

Has this happened since you (I assume) sorted out the overboost problem you had a couple of weeks ago? The most common place to get a leak I would expect to be in the fuel lines over the rear axle where they corrode but there is no reason I can think of for that to be worse under acceleration. In fact I can't think why it would leak anywhere under acceleration; the pump runs at the same speed all the time so when demand is least it will hit maximum pressure (most fuel returned to tank). Under load the injectors will be open more which would have the effect of taking pressure out of the system. Obviously the FPR is rising rate so it increases pressure in the fuel rail under load but it's a scary thought that you have a leak around there as it sits over the exhaust manifold. Could be one to get checked out pretty quickly even if it does cost money.

 

[skendrick]

Fen, this is still the same problem.

I had the car checked out by a specialist and he could not pin piont the problem. He drove the car to the rev limit with no problem then for no reason it killed the power and kangarooed down the road as said earlier. Since then I've been driving with the window down and found I can smell fuel very slightly but fuel nevertheless.

I thought it might be not enough fuel getting to the engine causing the EMS to cut the power under hard acceleration. It doesn't happen all the time so it is difficult to pinpoint the problem.

Steve

 

[Fen]

Mine once did something slightly similar when the fuel line was kinked during a filter change. Symptoms then were that it woul dbe fine for a while and get progressively worse in terms of not taking throttle until it got virtually undriveable. A short period being parked cured it for some miles. A friend (who is on here occasionally; AndyRR) had a similar thing with his S2 cab; it would be fine for 70 miles or so and then started to run really badly. I *think* that was something to do with the crank sensors.

 

[skendrick]

I have been driving my car for months with this problem and the car drives very well (even the specialist was impressed), but it only occurs if I floor the accelerator in 3rd, 4th or 5th from low revs (say 3000rpm). That why the specialist is unsure what the problem is.

I did notice this morning when I started the car up a strong smell of fuel so I will check all the fuel system this weekend to make sure all is well.

 

[Guest]

check the vac lines while you're at it. They control not only the FPR (which may point to the bad running), but also the check valve for the fuel vapour system. I've actually dumped that vapour valve, and I do notice a slight smell too, but at least I know why! []