850R No Spark, No OBDII, No Idea.

Badger operations · Post by **Badger operations** » 14 Jul 2018, 16:42

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. But am getting fuel pressure. I have checked ever single thread on this problem but still haven’t gotten anywhere with the car. I’m 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 powers up but doesn’t connect. (works on other cars). All of the lights on the dash light up except the check engine light.

My dad also has an 850r 1996 with a manual swap so I’m able to swap and compare sensors.

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, the gray fuel relay next to fan, swaped the J relays bellow the 101&102 relay, the ignition coil, ignition switch, fuses 1-35 are fine and not blown. The grounds are fine, the metal plate for the cam sensor is on right( not flipped), the distributor is in the correct position, the timing is spot on. The imobalizer is not on (sunroof and windows are working), new maf sensor.

My coil blue wire whe 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 battery is low and am charging it now.

Please help, any advice is welcome. Suggestions on resistance testing, guidelines for sensors to properly function, anything. We are stumped.

Post by **Clemens** » 14 Jul 2018, 17:21

Are all ground wires secured properly and in good shape?

Post by **misha** » 14 Jul 2018, 17:22

Ecu is not getting power,that's why you don't have a check engine light with key in pos.II. and no communication with scan tool.
If you have Vol-Fcr check codes for immobiliser.

The imobalizer is not on (sunroof and windows are working), new maf sensor.

Immobiliser have nothing to do with sunroof or windows...when immo is kicked in you will have red light in the middle of the dashboard ON and no start condition.

Triple check grounds...especially one on the transmission....since it's the only one which was removed.
Also check wires which goes to grey relay on fan shroud.It's a main fuel injection relay.
Does iac valve buzz when key is in pos II?

Post by **Clemens** » 14 Jul 2018, 17:24

Also: the alarm would kill the spark. But it would also turn on all blinkers and the 2 green arrows in the dash (and also the siren if still connected) if goes off.

Badger operations · Post by **Badger operations** » 14 Jul 2018, 17:55

Clemens wrote: ↑14 Jul 2018, 17:21 Are all ground wires secured properly and in good shape?

Yea they all checked out with the multimeter and seem to be in good condition.

shihabafi · Post by **shihabafi** » 14 Jul 2018, 20:09

What about your Throttle Position Sensor? Mine was just doing the same and a TPS swap did it. Well, to be fair, I also swapped out my ignition coil, and my grey relay.... and then I realized I had the wrong camshaft sensor... but yea somewhere along those lines...

Anyways don't just throw parts at it, go and actually test it. Check for sparks straight out of the ignition coil. Then act accordingly.

Badger operations · Post by **Badger operations** » 15 Jul 2018, 01:12

misha wrote: ↑14 Jul 2018, 17:22 Ecu is not getting power,that's why you don't have a check engine light with key in pos.II. and no communication with scan tool.
If you have Vol-Fcr check codes for immobiliser.
The imobalizer is not on (sunroof and windows are working), new maf sensor.
Immobiliser have nothing to do with sunroof or windows...when immo is kicked in you will have red light in the middle of the dashboard ON and no start condition.

Triple check grounds...especially one on the transmission....since it's the only one which was removed.
Also check wires which goes to grey relay on fan shroud.It's a main fuel injection relay.
Does iac valve buzz when key is in pos II?

I have checked the whole wireing harness, and have taken apart the ecu box. From there I inspected all of the wires and checked the continuity of the cam and crank. The ecu is getting 11.5v, checked the 1.0 red wire wich Supplied Power to ecu and tcu also checked gound wires on ecu and they checked out fine. The transmission ground is good and the two relays near the radiator are always buzzing.

Post by **misha** » 15 Jul 2018, 09:06

You missed something.
The fact that you don't have check engine light along with all other lights when key is in pos.II,means that ecu is not getting any power.
With symptoms you have i doubt that the bulb is burnt out in the process.
You mentioned that transmission is replaced...was it auto or manual like now?

dj_v70 · Post by **dj_v70** » 15 Jul 2018, 09:51

I concur with Misha. The fact that your primary ignition (coil input terminals) don’t vary (ie blue vs red) don’t vary while cranking means that ECU output isn’t working. This can be due to wiring, the ECU itself or ECU inputs like camshaft position sensor.

I am assuming that Misha knows (I don’t) that OBDII, and engine light are controlled by ECU also. Go to volvowiring.com to verify if you wish.

So, if multiple ECU outputs aren’t working, it is likely that ECU power, ground or the unit itself is bad.

Post by **Ozark Lee** » 15 Jul 2018, 16:28

Is the Idle Air Control Valve buzzing when you turn the ignition to Position II?

The master fuel system relay is conveniently located on the fan shroud (Gray relay, driver's side) and it is easy to snag the wires to it when you are doing something major under the hood. The relay itself rarely goes bad but the wires going to it can be trouble at the point where they go to the connector.

The symptoms are much like you describe and the idle air valve will be silent when there is trouble with that relay.

...Lee