GChat

Good day all,

I have an 89 S4 with a fuel issue. Recently it has needed extra cranking to start and a fuel smell. I realized that the fuel pressure is dropping as soon as the engine is off. After a few cycles of the fuel pump, pressure is back and ready to go. So, first thing I changed was the check valve and filter(not that the filter should make a difference, but it was time anyways). This made no difference when starting, but it seemed to have better low-end acceleration (just a feeling). Remaining is the hard starting and fuel smell. Checked the Y-connector at the charcoal canister, all is fine. Visually inspected the damper and return lines and no obvious leaks. No fuel smell when it is running and, from time to time, the system holds pressure and then the car starts as it should. So, I am wondering where to next. Injector? (I have run 2 tanks of cleaner with no discernable difference). Regulator? Dampner? I am unsure as to how these would allow the fuel to drain out. After the car sits, there is no fuel in the rail. I removed the pressure testing cap and no fuel.

Any comments/insights would be greatly appreciated.

Greg

GChat

Shameless bump. Any thoughts?

Could it be one injector doing this?

Greg

Jim R.

Greg,
I'm no expert, but since you already replaced the check valve at the fuel pump, you could have a leaking injector. How are you checking fuel pressure? Get a guage in the fuel rail and check idle pressure, then shut it down and check how long it takes the pressure to drop. As long as the check valve was installed correctly and is not defective, I would pull the injectors anyway and send them out to be flow tested and cleaned. Another possibility is a leaking fuel damper-I think you pull the vacuum line on each and look for fuel. You should not be smelling raw gas on a S4 unless there is a leak somewhere.

Good luck,

Jim R.

Gretch

second the previous post. There are 2 dampers and a FPR on your car, check the vacuum lines to each one. the FPR and the damper on the drivers side rear of the engine bay are obscured by the air box, remove that and pull the vacuum hoses off the units. if there is ANY sign of fuel in the hose you have a failed diaphram and need to replace it. the damper in the front of the engine is just in front of the drivers side fuel rail.

Note, leaking injectors can cause a serious problem........you really should get the fuel pressure gauge and make sure you don't have a bad one.

If you smell fuel it is because there is fuel OUTSIDE of the fuel system.