Running really rough afterbreakdown.

[Clan]

Originally Posted by cogs

Another few hours spent on the V40. I did a compression test, just in case, and everything seems fine, all four cylinders gave 170 reading.

As to the starting problem I think I found it.It seems there is no voltage getting to the MAF sensor. Reading between the thicker red power in wire and earth is a big fat zero. I double checked the fuses and changed the relay just in case and popped the bottom of the engine fuse box but nothing looks wrong.

I guess it might be a problem with a wire in the loom or the ecu .

That is the best clue you have given so far.. The power feed wires in the loom under the radiator going from one side to the other were rotting due to water ingress , this was over 10 years ago so yours could be in a bad state. pull the loom out strip the tape off and you might see swollen parts of the red insulation. Inside will be blue/white copper corrosion dust !

[cogs]

I finally got sometime on the V40. I repaired a suspect loom problem at a spot about eight inches down from the maf plug. This didn't help matters but fitting a new maf sensor did the trick.
My usual motor factors couldn't supply one and i couldn't afford volvos price but found one at europarts one make only starline. It fitted ok, the inlet going into the airbox was 1.65mm larger than original but pushed. I did 110mls in it today and she runs OK, well, back to how it was before breakdown anyway.

Thanks for help.