The Steinbauer BMWs:
Rick and Rainer's BMW
633 CSi (Igor)
3 Feb 18: Still drives funny and keeps dieing. Played around and I guess now that the in tank fuel pump
is not connected and the inline pump is failing. Very noisy and when the intank pump is connected the
fuse burns out. The fuse is the right rating (16 amp) but keeps burning out. I have a spare pump from
Victim which I will install next weekend.
That was not the case either. Decided to go with the in-tank pump option but that so far is nothing but
trouble. Igor seems to really like it in the garage. He just died in there. I thought that my AFM (Part
#13621359641 -Bosch #0280203002) died since it looked like it no longer sends a signal to the double
relay (1979 M90 L Jet engine) and hence the car does not run anymore.
I do have continuity from the battery to the fuse box and again to the double relay and continued from the
double relay to the fuel pump. If I jump the two connections by the double relay I get a humming from the
fuel pump. I understand that the AFM is supposed to send a signal to the double relay which kicks on the
power that gets the engine going when the flap opens in the AFM and it's also supposed to click. Well, it
does click but still no power to the pump. The thought that the DME is busted, since it smelled burned
had crossed my mind but according to the diagram the DME has no say in this.
Had the AFM open. Everything looked OK. With the ignition on I got power to port 39 and when I open the
flap power goes over to 36. So the micro switch seems to work. I checked continuity from both wires to the
double relay and we have continuity. I have an old double relay in and also connected the new relay and
still nothing. Lack of ground on 6 maybe? Is there any other item that would enable the power to the
So from the way it looks the AFM is good. I get 12V to the AFM and when the flap is opened 12V go out. I
measured at the connector by the relay. I can also hear the click at the relay. There is ground at #6 at
the AFM but only when the ignition is on. So from the way it looks the circuit is good there. Does the DME
provide input to the fuel pump power cicruit?
I ordered a DME, it arrived and I could not wait to plug it in. Plugged it in and measured for voltage at the
pump. YES!!!! I had what it takes! I put the thermostat housing back in (had to change the thermostat
since it was stuck in the open position due to the PO sticking a screw in there). Had some complications
since some of the screws broke due to old age and me beasting around (unrelated issue). Strange thing
is that for a while I have power at the pump regardless of ignition on or off and flap at AFM open or
closed. Did not last long though).
The car sat there for a while and when I tried it would not start anymore nor did I have current going to
the pump. If I apply 12V at the pump (bypassing everything going straight from the battery to the pump),
the car runs fine and as soon as I disconnect the power he dies.
I have to admit that I have not yet checked the red cable that leads from the ignition switch straight to the