'83 380sec won't start - PeachParts Mercedes-Benz Forum

MALK · #1 10-24-2016, 04:00 PM

hi all, got a sec that sits alot but gets started 2-3x a month until now of course. Usually starts first try-idles at 600rpm but tougher to start after been diven awhile. Now nothing,sputters and tries to start,starting fluid kicks it over no problem-runs few secs. IF I get it running it's because I'm pumping the gas and only at about 300rpm.
What I did,chg fuel pump & filter,jumpered fuel relay,plugs-rotor-cap-wires are only a month old,did run after they were changed. On fuel distributor,disconnected fuel lines on top-jumpered fuel relay-noticed fuel filling where the fuel lines came from equally,seems to drain once fuel relay jumper removed.. Also on fuel distr. steel line closests to front of car driver side,disconnected and spit fuel when cranking starter,reconnected,same side steel line closests firewall disconnected fuel slow poured out of distrib. when cranking. It seems a fuel problem,injectors? Don't know.What am I missing to do next?
thanks

Frank Reiner · #2 10-24-2016, 04:33 PM

M:

Consider the possibility of quite a bit of water in the tank, now being picked up in sufficient quantity as to prevent combustion.

Diseasel300 · #3 10-24-2016, 06:51 PM

^^^ x2

Been there. Done that. Pump some fuel out of your tank and let it settle in a glass jar overnight. See if you can see a division form (would be water/gas separation).

MALK · #4 10-24-2016, 10:32 PM

2 votes for water in the tank,,,worth a test -thanks

rwd4evr · #5 10-25-2016, 02:57 AM

Could be. Maybe fuel pressure being lost too. Just picked up a 380se euro car not to long ago and it runs fine but sometimes doesn't want to start even shortly after running. If you open the air cleaner and push the air valve with the key on it will squeal for a second. Then after that it fires right up. We're thinking leaky injectors not closing and letting the fuel pressure out.

Diseasel300 · #6 10-25-2016, 09:49 AM

OP stated that he's replaced the fuel pump and filter, then jumpered the fuel pump relay to confirm that fuel was being injected.

If water did get sucked up through the fuel system and sat for a period of time, it's possible that the injectors are seized and not "popping". Likewise if the fuel filter ruptured and let some crap through the lines, the little screens in the injectors could be clogged shut.

OP: Have you tried dumping a cap of fuel down the air inlet to see if the car will catch on fuel vapor? That would help rule out ignition issues.

MALK · #7 10-25-2016, 01:44 PM

took a cup sample of fuel from fuel distrib,-it was amber color and no fluid separation noticed.Pour little of that in throttle body -ran few secs. Checked plugs-all covered in 'soot' -replaced with good used ones-no chg.will run little from starting fluid.Never changed fuel accumalator but thought only effects 'hot' restarts-?-.Fuel is to distrib.-thru lines to injectors. Injectors?but all bad same time,it doesnt even badly.Is that something that is only replaced? Any thoughts?

Frank Reiner · #8 10-25-2016, 02:04 PM

M:

A second person will be required for this:
Depress the air flow sensor plate 1/2-3/4" while the engine is being cranked by your assistant. Use a long screw driver or piece of dowel to depress the plate. Depressing the plate will move the fuel metering plunger in the fuel distributor so that slightly more fuel is delivered to the nozzles.

MALK · #9 10-25-2016, 02:38 PM

ok,the more I repeatedly depress the air flow sensor plate 1/2'' or so the more it acts like it wants to start but never fully starts.What does that tell you and me?

Frank Reiner · #10 10-25-2016, 02:59 PM

Quote:

Originally Posted by MALK

ok,the more I repeatedly depress the air flow sensor plate 1/2'' or so the more it acts like it wants to start but never fully starts.What does that tell you and me?

The word "repeatedly" suggests that you are pushing the plate down and then letting it up, and then down & up, etc.
Push the plate down and hold it down, now go down 1". If the starting seems better, push down a little more.

If the starting is improving with increasing depression of the sensor plate, the next items on the list are the FD and the control pressure regulator (aka, warm up regulator>WUR).

Stretch · #11 10-25-2016, 03:00 PM

Before you go any further I'd check the air idle control valve tubing and make sure that all of that engine breathing / throttle plate by-pass tubing is securely fitted.

There's a pipework to the side and under my mixture unit - I guess there will be similar bits on yours

MALK · #12 10-25-2016, 03:45 PM

I was not pushing down and holding till it started-my helper left for the moment.Anyway,I'll be looking for parts now.The air control seems ok-rubber is old but one piece

Frank Reiner · #13 10-25-2016, 03:57 PM

M:

A couple of questions more:
1) How old is the fuel in the tank?
2) Does Florida gasoline contain ethanol?

MALK · #14 10-26-2016, 12:33 AM

1 gas station out of 100 has non-ethenol gas, and oddly I added 10 gals. gas,drove about 20 miles,parked it about 3 weeks later, here i am. I have my suspicions,I think i'll drain the tank since too many times it's the simplest of things. Going to get a WUV if it's the FD-I may have to tow it for repair because I have no idea how to setup a different FD. The SEC has such a great ride and handling hate to get rid of it but.....we'll see what happens.

Diseasel300 · #15 10-26-2016, 11:16 AM

Considering the car was running and driving, you filled it with gas, then parked and now it won't restart, I doubt very seriously that anything mechanical is wrong. I'd strongly suspect bad gas or water contamination.