2800 cs to 3.5 csi

[rsporsche]

my car was converted from a 2800 cs to a 3.5L L jet by the previous owner. the engine runs great ... the curious thing was that my fuel gauge didn't work ... checked the gauge connections, they hadn't come loose in the trailer trip to Georgia ... and yes, there is fuel in the tank. so i took the panels off the top of the tank ... and realize that it still has a cs tank.

my question is - what am i looking for to see if the return fuel circuit is present? in a csi, does the return line run back to the tank along the same route as the supply line?

second question - other than the tank, suction + sender, is there anything from a csi that i need or should have ... are any of the return lines metal tubing ... or is it all flexible fuel hose? the reason i ask is that i'm going to pick up a complete csi tank at the end of the week.

 

[x_atlas0]

Most of the fuel return circuits I have seen on other cars (my coupe included) are hard lines under the car, then soft in the engine bay and by the tank. The tank itself has a hard line connection where the return fuel dumps. It is usually not very much gas, so I have even seen some people leave it unconnected and simply run a long soft line to under the car, where it dumps the fuel.

 

[Honolulu]

it seems

that the OP stated his gage wasn't working. The fuel sender atop the tank is easy to check, using crossed screwdrivers to turn the sender about 1/4 turn ccw and out it will come.

Note that there is a tiny (2mm?) hole in the bottom of the aluminum cylinder that damps he surges of fuel in the tank, and it will take a minute or so to drain. Ergo, don't turn 1/4 then lift it all the way out or you'll have a bit of a mess.

Operationally ('scuse me if you already realize this) there is a float with a wire guide on either side, and two resistance wires running vertically, on which the float slides. High level, small resistance, gage reads more full. Low fuel, float low, high resistance, low gage reading.

Someone may have posted approximate resistance readings on this forum for highest and lowest float levels. You get to search, lucky.

Recall that the big o-ring that seals the sender to the tank should be either replaced (again, the correct size is posted somewhere) or let it dry out a day or so and (so I'm told) your can reinstall. A smidgen of lubricant might make the, um, sender... slide in easily.

go to!

 

[Bill Riblett]

Recall that the big o-ring that seals the sender to the tank should be either replaced (again, the correct size is posted somewhere) or let it dry out a day or so and (so I'm told) your can reinstall. A smidgen of lubricant might make the, um, sender... slide in easily.

go to!

That big o-ring is made of something that expands with contact with gasoline so you should only use the BMW part.