W116 450sel won't run

[Ben_sulzberger]

Hello
My father and I bought a 450sel and had it fully resprayed, before removing all the wiring, the car worked fine. Started up and ran like a dream. Then once we re installed all the electrical wires and everything else the car ran very poor and then wouldn't run at all. We took it to a mechanic and it ran well but then when putting it into reverse the car would stall if you didn't keep the revs up high and eventually wouldn't start. This repeated 3 time through 3 different mechanics and we gave up on the car. Recently we got motivated again and thought it would be a waist to leave it. We are buying another 450sel that has amazing cream interior and a running engine and we are going to swap the engine and interior. Before we change it is there anyone that would know what the issue could be? Also any advice for the engine swap?

[Tony From West Oz]

As you have already realised, removing the wiring and reconnecting it has caused this issue and it will not be fixed by replacing the engine.
You need to look at the wiring and see where you have incorrectly connected the wiring. You may find that an item (or items) have been damaged by the incorrect connection and to replace anything them.

Where are you located? Please edit your profile to show what part of the world you are located (City & State would be good)
That way members who have specific W116 450sel experience can chime in and hopefully help you out.

Me, I can help on W123 and W202 diesels, but not much more.

Tony

[Ben_sulzberger]

I'm in Albany Western Australia. There are no Mercedes shops around and no mechanic knows Mercedes good enough to fix anything.

Yeah we figured it would be a wiring issue but we just aren't sure where the issue is


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[Ben_sulzberger]

We will also be replacing the wiring along with the engine if we did. No just the engine


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[AMG]

First things first...
Before ripping into any task, you should have a copy of the factory MB service manual for your model.

In that respect, the forum sponsor sells hard copies on CD.

visit w116.org - get in touch with Michael Schlederer aka MForcer on this forum. He is a longtime contributor/supporter of ozbenz and his website and forum contains a wealth of detailed information, including schematics -

Don't attempt to do anything without first reviewing the electrical schematics in the factory service manual.

I can assure you that tracing the issue will be much faster if you follow the logic and the schematic diagrams.

If you find them difficult to read, you can take the PDF files to officeworks and have them enlarged / printed onto A0 size sheets.

I have done similar for my 124 and do not regret it - makes tracing a very simple and quick process.

[Ben_sulzberger]

Ok thanks. Will do now


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[TheMadRacoon]

What year is your 450? If it's pre-1976 I believe it will be d-jet fuel injection. If the car started and runs, but not well, it could be - if it is djet - that you have an inoperative or damaged sensor, or MAP (measures manifold pressure against ambient pressure) or, just due to age you might have a leaking cold start injector.

Check your spark plugs...are they fouled? Wet with fuel?

Again, if a d-jet fuel injection engine, do a search on this forum for "MAP", "d-jet", "injector" and "trigger points" as these seem to be parts that affect running. Also check fuel pressure, vacuum leaks. There are a number of helpful threads here, even if they cover M110 6-cyl and M116 V8 (3.5 / 3.8 / 4.2 litre d-jet engines) whereas your engine is the M117 V8.

[Ben_sulzberger]

We played around with the injecters for a bit. Had the warm up regular replaced. Spark plugs are good along with coil and leads. It did start perfect then got worse then runs fine but can't idle or start without a bit of throttle


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[Ben_sulzberger]

It is also the mechanical fuel system in the later models


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[AMG]

basic circuit testing of the fuel pump relay and pump circuits, and the ignition module circuit (TSZ4) should be carried out as a starting point. There is some information in the reference library section for the ignition and for CIS.

[Ben_sulzberger]

Ok thanks. We have done a few tests on the fuel pump recently but I will check again to make sure. After I go through the service manual.


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