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Hi Dave!
Yes the old DME-relay is underspecced.......at least one half of it. Iīm shure it is the one that closes and break the current supply to DME (computer) and the fuel injection valves. First you get a fixed current from relay to DME (key ON) but then you also have a pulsating curent through the injection valves that adds to the forementioned current when engine is running. The DME (computer) makes and break at pin 14 and 15 to ground thereby activate or deactivate injection valves (all four at he same time). The make time here is the length of time as the injectors are opened and fuel gets to the cylinders and and is dependant of engine temperature, air temperature, rpm, speed and load. So what we can understand from this is that if you are breaking a current through four coils (injectors) and knowing that this current now is inductive as in an ignition coil...this is really baaad for the relay contacts in operation....especially when you stop the engine.....you will have an arc over them like the old fashion breaker points.
Differece here is that you donīt have a capacitor to reduce arc (minimise induction) nor do you have a zener diode between live contact and ground.... and....and... so on. Really bad.
That is why I think a relay with heavier contacts will last longer (greater contact area and cooler) and this is what Íīve been testing now this summer with good result.
Unfortunately I wasnīt able to use my "new" relay in the same socket as the original one. Instead, I have a 2m long cable with six wires in it. One end is conncted to the relay and the other end finished with those crimping flat lugs that are so common now in electrical appli-cations. Three wires are 2,5 sqmm and three are 0,75 sqmm with lugs 6.3x0.8 mm and the other three are 2.6x0.8 mm I think. I lubricated them with dielectric grease before connecting them to relay socket to avoid any corrosion to come.
One idea is to cannibalise a bad DME-relay and use the bottom with flags to solder the wires to, put the plastic can on and use as a plug into the socket. Relay can be fixed somewhere under the dashboard as so many other relays are.
Car is jacked up for the winter but I will continue to make experiment with my single relay idea during the winter. Neither will this relay fit direct ino relay socket because of the different pin/flag layout. Connection will probably be the same as the forementioned. I will keep you posted. Cheers.
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Lapponia 1984 944 na
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