1978 280 SE - M110 116 024 trouble starting

[uniqbboy]

Hi everyone,
I am new to the forum, and need some help regarding my grandfathers MB. He imported a 1978 Mercedes Benz 280SE from Germany couple of years back. The chasis code is 116 024 the engine is inline six M110. The vehicle has 140,000 km about 86,000 miles, previous maintenace is unknown. The car worked fine untill few weeks ago, there was hesitation under load and it would sometimes stall when stopped. I went ahead and changed the oil and sparkplugs after that it wouldn't start.

Next thing i did is made sure all the plugs have correct gap (.029) and that all the wires are firmly fitting on top of the sparkplug. That checked out. Afther that i made sure all of them are getting spark by removing each sparkplug and wire and testing it for spark while cranking. They are all getting spark. So i figure it must a fuel problem than (past hesitation and there is spark as well as airflow). And yes there is fuel in the car. The fuel pump does turn on when given contact, and there is fuel coming to the injectors. However, not sure if there is adequate pressure.

Symptoms: Care hesitate while driving and stalled, after changing spark plugs and oil it wont start. It crancks at the starter but it wont start. Do these cars have a weak spot: fuel pump, fuel filter that gets cloged, issues with timing. I need help getting this car started. Please help, let me know if you need any other info? Thanks in advance

[uniqbboy]

Hi everyone,
I am new to the forum, and need some help regarding my grandfathers MB. He imported a 1978 Mercedes Benz 280SE from Germany couple of years back. The chasis code is 116 024 the engine is inline six M110. The vehicle has 140,000 km about 86,000 miles, previous maintenace is unknown. The car worked fine untill few weeks ago, there was hesitation under load and it would sometimes stall when stopped. I went ahead and changed the oil and sparkplugs after that it wouldn't start.

Next thing i did is made sure all the plugs have correct gap (.029) and that all the wires are firmly fitting on top of the sparkplug. That checked out. Afther that i made sure all of them are getting spark by removing each sparkplug and wire and testing it for spark while cranking. They are all getting spark. So i figure it must a fuel problem than (past hesitation and there is spark as well as airflow). And yes there is fuel in the car. The fuel pump does turn on when given contact, and there is fuel coming to the injectors. However, not sure if there is adequate pressure.

Symptoms: Care hesitate while driving and stalled, after changing spark plugs and oil it wont start. It crancks at the starter but it wont start. Do these cars have a weak spot: fuel pump, fuel filter that gets cloged, issues with timing. I need help getting this car started. Please help, let me know if you need any other info? Thanks in advance

[MunichTaxi]

You might want to drain the tank, and fuel system if over 6 months. Have you changed the fuel filter? If it is a canister type, is there water inside?

BTW, unless you check the firing order of the spark plug wires 3 times, you can't guarantee they are correct. The distributor rotor should turn clockwise; the firing order is stamped on the valve cover.

[300SDog]

And have ye tried starting fluid shot into intake manifold yet? Otherwise I'm thinkin the m110 twincam 280SEinspritzer makes lousy do-it-yerself project car, assuming its yer first MB. Can recommend ONE professional tuneup from the git-go and then perform routine maintenance from then yerself. Seriously 280SE creampuff low-mile w116's gettin scarce and the car deserves it. Plus with professional tuneup y'all git standard to judge how it oughta run - makin probs easier to solve and fix yerself down the road instaeda dealing with complex multi-probs from the start. Heck, the car sounds like a freebie - why not throw $500 under the hood to nearby MB tech and git it sorted?

(edit: General rules *before* attacking fuel feed is: 1) ignition system, blue spark not orange (coil, wires, distributor ground etc). 2) Valve timing adjust, ignition timing to spec. 3) Flush the fuel system "italian tuneup style" w/inline fuel filter, blow out dirty injectors, replace ALL fabric coated fuel lines from the tank, drain the tank and clean screen filter - hope'n pray ye aint got fuel pump issues.




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[uniqbboy]

Gasoline is not old in the car, the car ran untill two weeks ago. I have checked the firing order, it is correct.

The next thing i am concentrating is the plug wires, they look very very old like maybe even original. And they can build up resistance so new wires on the way and new fuel filter as well as rotor for distributor.

What is "Italian tuneup style" flush? I have already cleaned the injectors. I have already considered taking it to the Mercedes mechanic but i happen to live in Iowa, where closest MB dealership is 80 miles away and in general i don't trust them.

I will keep you posted on progess, does anyone have any other thoughts/

[ctaylor738]

Are you sure the pump is running while you crank?

How did you test fuel flow to the injectors?

[cheapold280ce]

First make sure the firing order is correct and you didn't cross any of the wires. It's stamp on the valve cover.

It would help to get a CIS fuel pressure guage to determine what is wrong.

If you don't have one then start by changing the fuel filter it may be clogged and if t's not well you should replace it anyway so you have a baseline of when a new filter was installed.

Next in the rear of car there is an accumulaor it's above the fuel filter has two lines on one side and a drain line on the back side going to the fuel dampener.

Take vise grips and clamp off the small hose going to back of accumulator. Take fuel line off back of accumulator. If fuel is coming out of accumulator it is bad. If fuel stops or if no fuel then take a miti-vac and and pull a vacumn on the back of accumulator it should hold vacumn if not replace it.

Other than that there isn't much you can do without fuel pressure guage.
It's time to bite bullet and get a set of guages.

[t walgamuth]

I would also check for loose vacuum hoses.

If the plug wires are wrong it would be firing at inappropriate times and backfiring and kicking back and so forth.

If you can shoot ether in the intake and it fires then its a fuel problem.

Tom W

[Larry Delor]

Might want to run some high quality fuel system cleaner in it. Things can get a little groady sometimes in those Jetronic distributors.