bazmonaut

I posted this question buried in a waaaaay too long post a couple of days ago...

My engine is flooding badly (fuel seeping through exhaust joints). I suspect that the diaphragms in one or more of the fuel pressure dampers/regulators have split, cuasing intake vacuum to suck fuel into the intake...

Question 1: I expect that the oil is probably contaminated with fuel, do I need to drain the oil before a start attempt? I am due an oil change anyway, but is it safe to let it warm up first?

Cheers

Barry '89 S4

WallyP

I would change it cold - if there is a lot of fuel in the oil, you can damage the engine very, very quickly. Not worth the risk.

Remember that you will still have some fuel in the oil that is left in the cooler, lines, etc. Give serious consideration to changing the oil again after you fix the problem.

aircooler

Hi Barry,

Sorry I can't be of much tech help, but if you say you are due an oil change, as well as having the slightest doubt, change the oil.

I would definitely sort that fuel issue first though. If you are worried about oil, a possible engine fire is far more possible, and pressing.

Best of luck,
Michael

the flyin' scotsman

Barry.............easy answer; even the most expensive oil change is peanuts compared to replacing the engine.............do as Walley says, change it now, fix the issue, get the engine going an fully warmed, change it again.

heinrich

A broken regulator will cause a car fire pronto!!!!!!!!!!!!

Jim bailey - 928 International

The fuel dampers and one pressure regulator (passenger rear fuel rail) all have vacuum lines into the intake . If a diaphram fails the vacuum line can become a fuel line but due to the rather small diameter it tends to make the engine very rich at idle but usually will fire and run at higher speed. A more common cause of excessive fuel for later cars would be L H Brain failure and run away cycling of all the injectors .

bazmonaut

Argh.

OK I will send out the brain for testing. Anyone know where to send it in the UK?

Is there any way to reliably test the diaphragms? Suck on a vacuum tube and see if I get a mouthful of fuel?

Cheers

Barry

bazmonaut

Just a thought - I have been unable to test the flywheel sensor (reference something), could this be the cause?

I am going to get a helper to crank it tonight while I stick a screwdriver to my ear and the other end on an injector - I should hear clicking, right? Approx how many clicks per second while cranking (or some other way to tell if it's going crazy)?

When my engine was rebuilt, the guy said that there was a fault in the LH - it is supposed to shut off fuel when you back off the throttle, but mine doesn't. He said it would not damage the car at all, however I am wondering whether this is an early sign of LH failure?

Cheers again

Barry

marton

Look at
http://www.jdsporsche.com/

good luck

Marton

FlyingDog

If the crank postition sensor isn't working, the injectors shouldn't fire. I'd recommend getting some cheap but acceptable oil to run for a short time until the problem is fixed. Then change it out again with the good stuff. I know oil is expensive over there, but as somebody already said, it's cheaper than a new engine.

Jim bailey - 928 International

Brain failure can be a progressive disease. You can check the dampers by carefully disconnecting the vacuum line best to push on another piece of hose hold the exposed end in a jar and have an assistant momentarily jumper the fuel pump relay (or crank the engine) no fuel should spray out the line from the vacuum port of the damper/regulators.