1973 450SE fuel / starting problem...

[tom in nh]

Hi all,
I have acquired a vintage Benz that is in great shape for 87K miles. It was towed to my place because it will not run. When cranking, she will start and then die after about 2-3 seconds - every time. If I spray starting fluid, she will stay running until I stop with the fluid. I also have a fuel leak (minor drips) at the fuel damper (rust causing a porous outer shell). Would a leak at the damper cause this? I could understand that a minor fuel leak will cause air to be sucked in, thereby creating a lower fuel delivery pressure - but to the point of dying out instantly? I am assuming that the damper is another term for pulsation control of the fuel pump. Could the trigger points in distributor cause this?
Anyone have a good source for used parts for this old girl? I am a tightwad that is willing to part out a donor car to save money .

Regards,
Tom

[j9fd3s]

in my experience fuel leaks usually wont stop the car from running. if it starts that means you're getting some kind of fuel delivery and then it stops when the car dies.

i can give you plenty of rx7 related examples, but i dont know enough about the mercedes to condemn any 1 part.

you're looking for something that would prime the fuel system, and then shut off when the cars running. ie it could be the fuel pump primes when you turn the key on, and then never runs again, or the injectors stop working (check with a light?)

mike

Greetings Tom...
I guess that this website info made it to you via our mutual fiend....
See, you have even received one response.
More will come.
Glad to have you aboard.
A helpful hint....use the SEARCH button above and type in your questions in a logical manner. The results will ASTOUND you!
See ya later bro.
spo out

[psfred]

Tom:

Could be a number of things, including a bad fuel pump.

Check the following:

Do the injectors click while cranking? If so, you have a fuel pressure problem. If not, it's electrical.

Can you get adequate fuel delivery? Does the pump hum when you turn the key on for about 2 sec, then shut off, and does it then run while cranking? If not, first check the relay, then check for a signal switching it on at the relay. No signal means bad wiring or a bad ECU.

Replace the damper if it's leaking, fuel leaks will be HUGE with this sytem (a quart in 30 sec is the fuel pump delivery spec with an open line....)

check the trigger points with a voltmeter making sure they open and close.

Check to make sure you have good connections on the two resistors in the ignition system -- if the first one in line has a bad connection, the engine will only run while cranking as the first resistor is bypassed while cranking.

Peter

[Tomguy]

Has it sat for any length of time?

Due to the regulator being rusty, and symptoms, it sounds like your injectors are stuck. Some kind of gunk from that regulator rusting had to have made its way into the injector's screens or maybe further, and also, possibly, gunk (old fuel that kinda turns into varnish) might be blocking them.

Take the injectors out and soak them in carb cleaner while you wait for your new regulator to arrive. I bet that they're clogged with rust, dirt, and anything you can imagine! Tip: To make sure each of mine worked properly, using a 12v (500mA?) transformer, I pulsed them a few times. I had one that didn't click at all - sign of a bad injector. I managed to free it up, but it leaked anyway, so I wound up replacing it - but once I did open it up, she sure ran better on all 8 cyls!