No fuel out of the fuel distributor. Why??? - PeachParts Mercedes-Benz Forum

Ron Johnstone · #1 05-18-2002, 07:03 PM

I have fuel pressure in the upper and lower chambers, (no gauge so don't know how much), the fuel is flowing back to the tank, but the problem seems to be there is absolutely no flow to the injectors at all. I've pulled the lines from the distributor while cranking the engine and no gasoline is coming out.

Am I faced with changing out the distributor or is there something else I can check that might be causing the problem?
The car is an 88 300 TE with the non-electronic injectors.

stevebfl · #2 05-18-2002, 07:41 PM

You need to have fuel pressure for the system to work. You can't condemn the distributor till you have checked fuel pressure.

Does the airflow meter flap offer resistance when the pump runs compared to when its not running. The pressure drops in half instantly on fuel pump shut-off this is a distinct difference in the feel of the flow plate. Jump the fuel pump to test the feel with pressure (?). Also while cranking try pushing down on the plate massive misaddjustment can keep fuel from flowing till large plate movements.

#3 05-19-2002, 06:08 PM

Hi I had a similar problem. Try this, tap the centre of the fuel distributor with the handle of a screw driver quite hard. Then disconect the electrohydraulic switch at the back of the distributor.
This worked for me as when the fuel cuts off on the over run it didn't come back on again. I tried another one and the car runs fine
Also when I was readjusting the air disc hight I once ended up with a mixture so weak the car would't start I solved this by turning the mixture screw, see your manual
Neil Farrow Exning Suffolf UK

Ron Johnstone · #4 05-20-2002, 04:20 PM

Steve, getting a bit ahead of myself, but just for planning purposes: If I procure a rebuilt fuel distributor, can I install it myself and expect the car to run well enough to drive it 20 miles or so to a good shop so they can properly adjust it? I just hate to get the car towed unless it is absolutely necessary

Ron Johnstone · #5 05-23-2002, 12:21 PM

I finally was able to borrow a fuel pressure gauge. Lower half pressure is 5.1 bar and it is 5.3 in the upper half of the fuel distributor. Absolutely no fuel is coming out of the exit ports to the injectors! The airflow flap seems smooth over its full travel.

Would a bad distributor result in all of the injector output ports being clogged, or is this perhaps a bad actuator arm that is causing the distributor to not come on line at all?

stevebfl · #6 05-23-2002, 12:52 PM

Have you pushed the airflow meter flap down while having these fuel pressures. If no fuel flows under those conditions the problem is in the fuel distributor. If it only doesn't flow at rest then thats the way its supposed to.

Your lower chamber pressures should be .4 to .5 bar lower than the upper chamber pressure. Disconnect the EHA and check the differential pressure. You have only .2 bar differential press right now and that could easily keep the car from starting. You should have about .4 bar with the EHA disconnected (electrically).

Tell me what happens when you push the flap down.

Ron Johnstone · #7 06-10-2002, 05:02 PM

Just to wind up this thread, I had the car towed to European Motor Cars in Redwood City, near where I work. Otto couldn't find out what was the matter, ran all sorts of tests and checked all over the engine, including compression, camshaft timing, ignition timing, put in a new set of plugs, etc., etc. Finally, he got it to start, it ran very rough with clouds of black smoke, then it let a hell of a backfire and has run fine ever since. He has no idea of what the problem was, but the backfire seemed to cure it.