Hey all,

I've had this car for a few months now. Got it from some guy who had it sitting since '05. It needed head work done so I go that squared away and now that it's back together (after a few months) it doesn't want to start. There is fuel going to the injectors but thats where it stops. I took the injectors out and did a nice thorough check to see if they were clogged or not, they were not clogged, so my guess is that the fuel pump is going bad and can't get enough pressure into the system to make the valves move. It's a 1988 300E Saloon with the M103. It has mechanical injectors. I checked the timing three times since and it hasn't skipped at all and the spark plugs are in their correct places (as well as brand new with new wires) and there is fuel in the tank about 5 gallons. It seems though that I might not be getting enough pressure in my system to have the fuel spray through the injectors. I hear the fuel pump working when I turn the key to the on position, but the car refuses to start, and the fuel stops at the injectors which aren't clogged or seized up. No leaks anywhere either. So should I do a pressure test and go from there?

 

i think you should first spray some starting fluid into the throttle body and try to start it. to see if it will start and run, do you have enough battery power to start the car. is it cranking fast enough? is the engine getting spark? i would go with a new pump..actually your car has 2 of them i think and a new fuel filter to start.

 

I tried starting fluid, it starts with that but when all the fumes are used up it shuts off, I have spark, it cranks fast enough, theres enough battery power cuz I keep it charged. I tried it all already, all I can think is that the fuel pump is going bad or something along those lines.

 

These older fuel pump are tested not by pressure but by volume. The pump should give you about 1L (qt.) of fuel in 30 seconds from supply hose removed from fuel distributor. Mechanical injectors need about 50-55 psi to operate. Check screen for dirt inside the supply hose inlet of the fuel distributor, checkvalve right next to the inlet (if it's stuck open, your fuel is flowing back to tank) or warm up regulator screwed to the side of engine (if your M103 is equiped with it, my M110 is). There is also screen inside of the input hose fitting, as in the fuel distributor. Rust from lines could of brake loose after sitting for so long and moved towards the engine. Good luck.

 

Yeah I was reading up on about the 50 psi for the valves and stuff just now. I'll be sure to check all that on Sunday, and I'll give a verdict then, thanks a bunch.

 

So...I've been gone for a few months on business and well I was going insane as to what could be the reason why it won't start...so after pulling out all my hair I finally got a break to go home and the first thing I did was open up the hood, and I realized that a vacuum line was missing from the intake manifold and valve cover...I bought a new one and when I tried to crank it over viola it was alive again...I'm a complete moron...but hey it now runs and works...however it still needs much TLC because of the owner before me didn't care much about it obviously...so I still have a lot of work ahead of me, my questions is, what's a good after market exhaust I should put on her?