96 850 no spark

[joaa]

I'm working on a 96 850 with no spark. The owner has already changed the cam and crank sensor both new and a new coil. Also the ECM was changed but with a used one. Still no spark .
The owner also said last year he had to turn the key back off then back on before it would do anything but it hasnt done it for a year or more. Ignition switch maybe?
I tested at the coil with my logic tester and power but no pulse. Any ideas? All ideas appreciated and thankful for.

[jreed]

Interesting problem... just confirming that the car cranks but does not start?

[greg850r]

I would recheck the connections and routing of cam sensor and crank sensor. The plugs get brittle and fall apart over time. Next I'd throw a cap and rotor at it. I chased one of these for a very long time. Bad ground could do it. Mine turned out to be loose positive cable at the starter causing intermittent interruptions to 12v at ECU.

[dj_v70]

a) Did you use your logic probe to test crankshaft/cam sensors at ECU connector?
b) If you have 12V on high side of coil then ignition switch is at least partially working. Did you test for power at ECU?
c) Did you test wire from ECU to coil?

[erikv11]

... The owner also said last year he had to turn the key back off then back on before it would do anything but it hasnt done it for a year or more. Ignition switch maybe?
...

Given that the electrical part of this switch is extremely common to fail, if troubleshooting is going nowhere I'd swap in a known working one. E.g. any ignition switch at the junkyard will be a working one.

[RickHaleParker]

I tested at the coil with my logic tester and power but no pulse.

Before or after the DI Power Stage?

[joaa]

Sorry guys I got busy. I run my own shop but very few imports get this deep in the woods. Anyway back to my Volvo problem, So far all Ive tested were the contacts on the coil itself. Correct me if I'm wrong-- shouldn't the negative side of the coil pulse as the engine cranks?
I've cleaned and replaced all the grounds I could find body and motor still no fire. Ideas? BTW thanks for the quick replies!

[RickHaleParker]

Correct me if I'm wrong-- shouldn't the negative side of the coil pulse as the engine cranks?

On the Coil's primary side or DI power stage output (Solid Red & Solid Blue) it should pulse.

If there is no pulse from the ECM (Yellow/White), No DI Power stage 12V supply (Blue/Red) , No DI Power stage ground (Solid Black) or DI power stage is defective you won't.

The DI power stage is mounted on the same bracket as the coil.

Volvo_Coil.png (145.93 KiB) Viewed 72 times

[joaa]

The DI is new along with the new coil which I've found makes no difference. I've gotten bad new parts before. I'll do some more checking this evening after work and let you know what I find. Again thank you