Hi guys,
I have a 1997 volvo 850r. I just have replaced the head gasket along with the m56 transmission. When I purchased the car the swap was already done, but needed another m56 cause syncro in gear 3 was gone.

Got the car all back together but the car would not want to start. No spark, except for one time. The spark lasted about 5 mins and then the spark disappeared. When car was getting spark it was not wanting to start up so we checked compression which is fine. Half way through the compression test we did loose spark. After we lost spark we connected a noid lite to the fuel injector which never lite up. I have checked ever single thread on this problem but still haven’t gotten anywhere with the car. Im also not able to connect with the obd2. I checked the obd2 power and am getting 12v (black in 4 red in 16). The code reader never connects (works on other cars). All of the lights on the dash light up except the check engine light.
I have swapped the ecu, cam sensor, crank sensor, change the polarity of the crank sensor (never touched or changed the fly wheel), the red 103 fuel relay, change the gray fuel relay next to fan, changed all the J relays next to relay 101 and 102,

My coil blue wire when key is in position 3 is reading at 10.76v and 10v when cranking.My coil red wire when key is in position 3 is reading at 10.76v and 10v when cranking. I know the bater is low and am charging it now.

 

If you are sure that you are losing spark then that's the area to focus. I am concerned that you have no check engine light and you are going to have to determine if that's a burned out bulb or lack of power to the circuit.

 

Thank you tony, was planing on opening up the dash today. If the check engine light bulb is out wouldn't I still be able to read codes? Also I recreated this post on a different thread with more information. Was trying to figure out how to delete this one. Once again thank you so much for responding quickly.

Link to new thread.
https://volvoforums.com/forum/volvo-...k-obdii-97053/