1990 Volvo 740 GLE wagon. Having a 'no spark' issue. I fear the RPM sensor is the source of my problem, but I dont want to end up replacing a working one. Does anyone know how to test the RPM sensor?? Thanks in advance

 

How does it look?
If the outer sheilding is cracked or falling apart replace it.

BTW I moved it to the proper section.

 

I cant see the sensor itself since it is behind the motor on the bellhousing however, the 'sheilding' or foil wrapped around the outside of the 3wires coming from it is cracked and frayed. Is this what you mean?

btw what forum did you move this to? I couldnt find anything more specific than this section. I apoligize...

 

If you see the foil then all the black insulation is all gone already. I would replace it and see if you have spark then.
Those wires need to be totally sealed up.

I moved it to the 240,740,940 section you had it in the V40 section.

 

It looks like Ill need to pull the trans to replace it, not to mention a new one is pretty expensive. I nned to know if there is a procedure to test it while installed.I need a definitive answer as to whether it is working or not. I do haveDVM. Anyone with any info would be greatly appreciated.

 

You don't need to pull the tranny only 1 screw holds it in.

Thats what you need.

http://www.fcpgroton.com/product-exe...ategory_id/116

 

Also sorry I don't have the specs but if the tach doesn't move that usually means the sensor is toast.

 

Thanks. That sensor is for an 8-valve engine mine is 16v, are thewy the same?

 

Yes it looks like it here is the one for the 16V.
http://www.fcpgroton.com/product-exe...ategory_id/116

 

Thanks for your help I appreciate it

 

No problem anytime.
Also here is a pic looking down at the speed sensor as well from the top. To show the screw.

 

Go to www.stepbystepvolvo.com for free diagnostic guide for 740 no-starts. No spark has 3 main culprits: RPM sensor, Power Stage, or ignition coil.