|
Here, as promised, are those page references from Haynes.
4A-24 Shows the LH 2.2, in which power is supplied directly from the battery to the relay. Post relay, the in-tank pump is fused on #4, but judging from this diagram, the main pump is not fused at all. As this is an LH 2.2 system, the #6 fuse has nothing to do with it, either on paper or in reality. Note: this diagram was not in the Volvo service manual I saw, although the CIS before it was, as was the LH 2.4 and LH 3.1. I didn't get the logic there, either.
4A-25 Shows the LH 2.4, in which, according to the diagram, power is supplied from the battery to the junction block (the one between the 25A fuse and the headlight relay, right?), to fuse #6. From the other side of fuse #6, two (not one, but two!) red wires go to exactly the same place, connecting just a few inches and a few corners away, then splitting off to supply power at terminal 4 of the FI brain, terminal 5 of the ignition brain, and the fuel pump relay. Power out of terminal 5 of the relay (connected to power when the relay is tripped), goes to fuse #4, on the other side of which, it flows out to heat the 02 sensor and power the in-tank pump--BUT--before going through fuse #4, it glances off to power the main pump. Note: the 25A fuse is not on this diagram at all, just another clue that it is incorrect.
4A-26. Shows the LH 3.1, in which all germaine points on the diagram are the same as for the LH 2.4.
It also occurred to me that, if the power to the FI and ignition control units really did go through fuse #6, then there's no way the car would start or run with fuse #6 out. So, the published fuel pressure relief procedure can't be correct. I guess that bears out the idea that my fuel pressure regulator really did need to be replaced.
So, you've got a convert in me, so to speak. I am still forced to wonder, though: how can all these published sources, even straight from Volvo, be so blatantly wrong? If it weren't for the info you provided, and for the obvious fallacy in the above paragraph, I would have assumed that my car was the victim of a hack modification to the fuel system wiring. I'm relieved to find that's not the case.
-EdM.
|
