Quote:
Originally Posted by sixto
Fuel enrichment relay in an '85 TD? IIRC fuel enrichment is mechanical with a vacuum switchover valve in the circuit to cut the boost signal to the fuel [de]enrichment device.
As to how it works, there's a device atop the IP called the ALDA. Absent a boost signal from the intake manifold, the ALDA presses down on a plunger in the IP to restrict fuel to about as much as a naturally aspirated engine can handle. As manifold boost builds, a boost signal is piped to the ALDA which responds by releasing pressure on the IP plunger, allowing more fuel in relation to a denser air charge into the cylinders. The overboost circuit has a 1.0-1.1 bar switch in manifold. At the setpoint, presumably because the turbo has lost its ability to limit to boost to levels safe for the engine, the switch completes a solenoid circuit within the switchover valve to cut the boost signal to the ALDA. The engine is essentially limited to it's naturally aspirated equivalent's fuel supply until manifold pressure drops below the overboost setpoint.
Sixto
87 300D
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Sixto, THANK YOU SO VERY MUCH!
I do not have an A.L.D.A. as was broke when I bought the Mercedes (would not hold vacuum and the screws are corroded into the hosing). Figured I didn't need it, but the more that I know, the more I disagree with those that say fine to run without. Trouble is finding one that holds vacuum or can be repaired.
Very few on here can or able to answer questions, so had to make my own path. I might be further along if I had more help, but at the same time feel retaining more by making the mistakes. Thus why I did some things wrong that need correcting.
So, what is this part mounted to the firewall? Looks hooked into the transmission system.
I found the one I was looking for by looking up the A.L.D.A.,
so will get that addressed.