Squatting Ninja

Hey guys,

My 90' S2 is running rich, before I go on the expensive route of just changing parts, are there any tests you would suggest I do?

The car idles smoothly and runs fine on acceleration but it feels like it should have a bit more mid-range power than it actually does too.

It is running rich to the point that it will soot up my rear bumper in no time at all and blow out some black smoke while revving it up, when I release the gas you can actually hear the occasional pop and its drinking petrol like crazy too (obviously).

The air filter is clean and the vacuum readings are stable and correct.

What tests would you suggest I do to help diagnose the problem?

Cheers!

mikey_audiogeek

Fuel pressure regulators are known to fail high. Check fuel pressure. Eventually the fuel pressure gets so high that the computer shuts down the fuel injectors and the car won't start. Ask me how I know.

Cheers,
Mike

944meister

Check the fuel pressure at the rail. have you changed or checked the spark plugs, dist. cap and rotor?

Squatting Ninja

Cheers guys, much appreciated!

Ill check the fuel pressure at the rail in a few hours and post the results. Ill also make sure its holding pressure to the injectors and they are not leaking at the same time.

Im being lazy here but does anyone know off-hand the system and control pressure of the S2?

Plugs, dist. cap, rotor and leads are all in the PO's file as being changed 1100 miles ago but ill give them a proper once over at first daylight.

Cheers again, will update soon.

Squatting Ninja

I was just being a little lazy asking for pressure figures, incase someone finds this thread in the future and needs to do a similar test, all the information is found here:
http://www.clarks-garage.com/shop-manual/fuel-01.htm

Good night all

hamlin

Don't forget the fule pressure dampner, this is a common failure that results in raw fuel being sucked into the bottom of the intake manifold, mine failed aroung 45,000 resulting in running rich and hard starts.

944meister

i believe having unstable pressure at the rail will tell if the dampner is failing.

hamlin

Actually, the easiest way to tell if the dampner has failed is to pull the vacuum tubing off the end if fuel is present it is defective and is leaking.