Help needed
 

Hi guys new to the forum. I have a 1998 940 b230fk that will not start it has been stood for over a year.

I have followed the checks for all the relays and power stage and everything. But still no luck.

I am missing the 12v feed to the crank sensor but im getting no fuel or no spark

I really need some help

Thanks

Hi Sam and welcome to the forum.

Others on here know more than me but as a start, if there is no feed to the crank sensor then the ECU will not know that the engine is turning and will not pump fuel. Suggest you tackle the missing power feed to the crank sensor first.

Good luck,
LeeP

Errr, you don't need help, you've unwittingly found the fault! :thumbs_up:

The fault is the RSR - Radio Suppression Relay - located either near the coolant expansion tank or on the near side inner wing.

If you have an electric cooling fan, the relays are identical (if you've got A/C on it, there will be an electric fan in front of the rad as well as the viscous fan on the engine) and are usually mounted side by side so are easy to swap over for checking.

https://i.ebayimg.com/images/g/DRIAA...Ol/s-l1600.jpg

https://www.ebay.co.uk/itm/VOLVO-CAR...qkOl:rk:5:pf:1

That's a photo borrowed from the listing so you can see what it looks like and a link to the listing as well. Once you've located the relay, in the plug that goes onto it there are two thick cables - if you link those out, it should start. That will prove the relay is the fault, you then have to work out if the relay is not getting a signal or not switching. If you've narrowed it down this far, you should be good to do that.

Also check your fuses, the pump may be sticky and popped a fuse on trying to start. ;) :D

Brilliant cheers i thought i had checked the suppression relay but obviously have checked the wrong one haha the on i checked only had one thick blue wire and the rest were green. I will get on this tonight thanks for the reply

If memory serves, it's one thick red, one thick blue and the other two are green with a coloured stripe and green with a black stripe. I think!

Sounds very like you've got the cooling fan one there!

Bridged the red and blue wires together and still nothing. I have 12v at those wires as i checked the ballast resistor after that relay hence my stupidity with the blue and green wires. I think the icu may be bad. I am also getting no fuel but this i think is to do with the crank sensor too

There is no power supply to the crank sensor.

Is the tach jumping when cranking?

No its not. I have the 5v and earth just no 12v

The crank sensor makes its own voltage. Not sure where the 5v is coming from. One of the three pins just goes to a shielding wire. It's difficult to measure the voltage that the crank sensor creates whilst cranking in my experience. Easier to measure pin 5 (i think) of the plug going to the ignition amplifier. This is the trigger signal from the Ezk.

You have a 5V feed and an earth on the CPS? Why are you expecting to see a 12V feed as well? The third pin is the output.

Did you check the fuses? Have you tried feeding the fuel pump directly? In the boot, there's a panel in the floor on the left of the spare wheel well, lift it up. You should find a 3-pin multiplug and socket with a pink wire, a black wire and a third wire.

Feed +12V into the pink and 0V/earth the black wire. You should hear the pump run if it's capable of running.