1994 volvo 850 will not start. No spark. Fuel pump pressure good. Both ecu's* good, all sensors good, (except did not test coolant temp sensor). Coil* and ignitor* good. (*Tested these items in an other car). Power to coil good but have not tested frequency to coil.

Now I am looking for posible wire damage from mice and/or oil.
(These volvo wiring harnesses are very durable and connectors I have checked look fine. Oil has not appeared to of damaged the insulation either.)

Question. What will cause this?
Test lead in the A-2 pin location shows only a faint glow. Can not read codes at this A-2 pin. All other dtc's are readable.

Just learned that A-2 pin deals with fuel injection, and the A-6 pin codes deal with igntion/spark. Planning to read A-6 codes soon.
Checked A-6 pin.

NOTE: Can not read A-6 pin either.

superdave

 

Superdave here

An answer to why "1994 volvo 850 will not start"

We found out what was wrong! The MAIN RELAY of which no mention of it exists in any troubleshooting documentation dealer or otherwise had broken corroded wire connections to it. It was found by "chance" as we assumed wires must be damaged at some point somewhere. But where? The wiring harnesses on these 850's is extremely durable. We looked for cuts from mice and found none.
The MAIN RELAY is located under the shield that covers the top of the radiator.

Only took 6 months to find
Superdave

 

Glad you found it.