M117 wont idle

[Tony66_au]

Gents I've decided to have a red hot go at sorting the fuel injection on my 450 and I need help.

The issue is that the car wont start on fuel unless I have my foot half way down on the throttle.

The car wont idle on fuel

The engine runs fine above 2000 rpm, drop it below 2k and it stumbles and dies instantly, so fast I cant catch it and blip it back to life.

Im a complete moron with mechanical fuel injection.

And lastly what sort of injection is on the 1977 450SE, K jet or D jet, full mech or some electronic?

The car runs ok on LPG but I really want both running as I do like to run at least a tank a month in Petrol on dual fuel cars.

Thanks in Advance,

Tony

 

[SEL_69L]

From what you are saying your 450SE is set up as a dual fueller.

In a similar case of the MB Club Pres., who had the same setup in a 450 SE as well, the problem was eventually traced, after many frustrating months, to a small air leak in the fuel supply. The history of his problems was documented in the MB Club of Vic. Magazine. I can't remember if the air leak was on the petrol or the LPG side.

 

[Tony66_au]

From what you are saying your 450SE is set up as a dual fueller.

In a similar case of the MB Club Pres., who had the same setup in a 450 SE as well, the problem was eventually traced, after many frustrating months, to a small air leak in the fuel supply. The history of his problems was documented in the MB Club of Vic. Magazine. I can't remember if the air leak was on the petrol or the LPG side.

Yes it is a Dual fueler and it runs ok-ish on gas but id rather it run well on petrol.

I had a play with the plastic idle screw at the front of the engine which was 3/4's of a turn clockwise to being screwed all the way in when i first started playing and is now 2 3/4 turns open from fully closed with the only result being that she now wont idle under 2800 rpm lol

Looks like im going to have to start from scratch at this stage and begin with the vacuum lines, delete the air injection system and block some pipes and then perhaps source new injectors and have a good look at the injection system from end to end.

I guess if the vac system is all a known good quantity then half my work is done.

Im also tempted to disable the LPG system, shut the master valve at the gas tank and work forward from there.

Other option is to start buying parts, injectors, sensors etc and hand the old girl to a guy I know in Elmore who is an LPG wiz with Old Benz experience and hope it doesnt cost too much.

Im a bit all over the place strategy wise at the moment but im sure I will find a path similar to one or all of the above.

Cheers,
Tony

 

[John S]

Throwing parts at any problem with a Mercedes ends up costing a fortune. You will be much better off if you can find someone who knows the W116's well and have the problem diagnosed first.

 

[Tony66_au]

Throwing parts at any problem with a Mercedes ends up costing a fortune. You will be much better off if you can find someone who knows the W116's well and have the problem diagnosed first.

True.

But my reasoning is that sooner or later these bits and pieces will need replacing although I haven't priced any of it as yet so I might end up eating my words lol