A year later:problem is still there,I left it this way last year because the car passed the emissions(because they didn't check:) and I replaced already so many parts that I got tired of looking at it.Also found out that somebody else(Mercedes shop) already played with it before my girlfriend bought the car already,but couldn't find it either.
But this year it failed emmisions:co of more then 10(!) where the book says 0,5 %.
BTW:Car is a 92- 300 ce U9 m103 with 5 speed manual gearbox,no airco,KE-jetronic.
Yesterday warmed up the car,shut it off,put the ignition 5 times on (for 2 seconds),full throttle,started and yes ! :7000 rpm for a second,then it went back to the dreadful 4500 rpm and hesitate again.Lot's of black smoke,bad mpg but it drives ok and starts fine.
So in my opinion it has to do with not enough fuel or fuel pressure.Last year I replaced already the filter,both the pumps are working,I tested this with some sort of stetiscope and heared them both ,although one had a slightly lower tone.
Since I don't have the tools to measure the fuel pressure is there another way to determine if the pumps are the fault or that the fuel pressure regulator is the problem?
Any other suggestions are very welcome too,since my girlfriend drives now a bike and doesn't feel too happy.
Thanks in advance and