Mercedes-Benz Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
1990 300E fuel starvation after 10 minutes. New pumps, new filter, checked fuel accumulator, has power to pumps. Should I buy a pressure gauge (S&G Tool 36250 at Amazon for $90) or just replace the fuel pressure regulator?
 

·
Premium Member
Joined
·
5,454 Posts
You don't say how many miles are on the car. A fuel pressure regulator is pretty pricey to install as a Hail Mary pass so I'd get a fuel pressure gauge first to see what's going on.

What are the symptoms? Poor throttle response? Bogging? Why are you saying fuel starvation?

One possible cause of fuel starvation is the fine screen at the tank suction fitting. This can be replaced but it is a real mess to do so. You have to get just about every drop of gas out of the tank or you'll get a bath when you unscrew the fitting.

Another potential cause of problems is the fuel distributor. I've been reading up on them and the barrel that moves up and down inside them to deliver more/less fuel has slits 0.2mm wide. Dirt or varnish that gets in there is a nightmare.
 

Attachments

·
Registered
Joined
·
51 Posts
Discussion Starter #3
Vehicle has 213k miles and is well maintained. Sitting in the driveway giving it some gas, after 10 to 15 minutes it starts to miss and then finally dies and will not restart for hours. I tried another fuel pressure regulator today and no change.
 

·
Premium Member
Joined
·
10,120 Posts
It might not be a fuel delivery problem at all, but electronics heating up and failing. Try another MAS unit of the same yr from a pick & pull and make sure your OVP is 100% Could even be a failing/dirty CPS.....no harm to check that out. Get a code reader and do a code search.

Kevin
 

·
Registered
Joined
·
51 Posts
Discussion Starter #6
The vehicle appears to be fixed. It has been ok for 2 months now. I believe the indy shop misdiagnoised the problem as fuel pumps. Replaced the fuel pumps, OVP relay and CPS but same problem. I went back to basics and changed the distributor cap, rotor and 40k Bosch platinum spark plugs with standard copper plugs and no more problem. Always take care of the basics first!
 
1 - 6 of 6 Posts
Top