Over fuelling Issue, W116 350SE 1974

Looking for help with an over fueling issue. Problem started after car stood for a year or more. First diagnosed ECU, replaced this. Then car would swing but not start. after much trying discovered fuel getting into oil and having to drain and refill. injectors all checked with individual cups underneath each. check rail in and out pipes from tank to damper to pressure regulator, fuel not getting through the pressure regulator. Car swings powerfully until battery runs out but does not start. Was able to get it running for a few minutes with a T piece bypassing both damper and regulator. Put everything back as it should be, including new fuel pipe everywhere but still the same.
Any ideas and help please. I am trying to find another pressure regulator, but have three second hand ones here and its unlikely that all three are blocked or faulty

Thanks William Davy
South Africa.

Good Day Volker
Sir i think that's part of the problem. I don't have it that way. The fuel line must go directly onto the rail. is it posssible to describe the sequence as I just checked now and there is a return pipe as well which I assume the damper out pipe must be connected to. There are three pipes on the pressure regulator though and I am not sure where the out going part goes. is it possible for me to send picture which should help?

Hi Volker
Thanks for the prompt response. I am still getting used to your website and not sure where to see the picture.

Oh sherbet I am being stupid I see the link in your earlier response.
Thanks a million I am going to try this and will let you know later.

Good afternoon Volker
I have placed all the fuel pipes in their correct places secured them and tried to start. IT swung strongly but did not start except for a short stutter after I put some fuel into the big intake under the filter. I am not a mechanic so don't know all the terms. The previous mechanic who struggled with this eventually had to replace oil as the over fueling was getting into the oil. I have another pressure regulator that I can test, also there is very little fuel in the tank which I must fill.
what do you suggest and what can I do next? Its lock down here so I have the time hence I am trying to solve this problem which has persisted for months now.

Volker
The last person did that and it came out correct 2 bars I think both sides. The person also tried an of the shelf "grey" fuel pressure regulator to see whether that would work, and it did not. But I will measure. How does one measure and how does one adjust the pressure?
I am sorry to ask all these questions but I am not a mechanic and really appreciate your help.
William

Hi Volker
You are correct when testing on Saturday the fuel did fly out when opening hoses as the pressure was great.
I will get a meter and test the pressure whilst swinging the engine I assume.
I will also adjust the regulator as you say.
Should I also not try the other regulator I have?
what must the pressure be and if its below what do I do?
This I will do tomorrow or as soon as I get that meter and then come back to you.

Thanks again
william
By the way, is all this for free? Should we not be paying you for all this?

Good Day Volker
I have not made any progress yet but will come back to you once I have a fuel pressure tester.
I wanted to ask whether you know where I can get a EFAW 228 tester or the Porch one you suggested in europe. I have been on Ebay have not found any.

Thanks William

Hi Volker
I have a mechanic friend who is an old time expert on the W116 as well and other mercs. He has worked on my cars for years. He started as a young apprentice working on W116's years ago. He told me about this machine two years ago and now you as well. He is changing his car repair business to focus on doing only restorations of old Mercs. Big interest in old mercs here and big business. we have been looking for a machine for two years. He even went back to an old firm before they closed down to try and get the machine he used there. He knows it well. We are prepared to pay any of the costs as well as what ever you want for the machines. All it requires is boxing it up and DHL to my address. we will not pay much duty here as its very old equipment and we can put a low price on it, Please Please Sir we would do anything to get one of each of these machines. It would help me to get my cars back to 100% and him in his business.
Let me know and thanks again for all your help.

Hi,

if you would like to pay any price, look here:

www.ebay-kleinanzeigen.de/s-anzeige/d-je.../1390834877-223-1930

But be aware that you would spoil the market if you do so.

Best regards,
Recardo

Hi,

I found one on ebay for less than 300€. But there was something wrong with the address. Possibly some fake.

Recardo

Good Day Volker
Its been lock down here and we have not been able to move for a few months. I am just making contact to say that I am still interested in the machine. I have also not been able to do my fuel pressure test as yet.

I have often come across this on Older Mercedes with Djet. I have found that one of two injectors are faulty and the car runs poorly, so someone gets the bright idea to up the pressure . I am tuning a 3.5 300SEL right now which had 34PSi . Adjusting it back to 28PSi has stopped it running rich but one leaky injector (#6) causes the pressure to drop off drastically under acceleration and foul number six plug. I don't use a tester machine for testing the various components ,Just a snap on multimeter . It only takes 30 minutes to go over everything. As a side note, you can buy a pressure gauge at any auto parts place in ZA, you don't need anything too fancy (or expensive) Mine is just an old Oil pressure gauge.