97 model 850 stopped. No spark.

SouthernMan · Post by **SouthernMan** » 06 Oct 2017, 20:21

Hi, I was away on a journey when my 850 stopped. First lost power and ran rough for a few moments then stopped and would not start again.
Roadside assistance found that it had fuel delivery but no spark. Checked coil and said it was likely faulty.
Towed to Volvo mechanic and reports that the coil is ok but problem lies deeper. Probably ecu burned out due to possible wiring issue? Says due to the age of the vehicle that it is not worth investigating further.
Car is very sound and I recently performed major service, timing belt, water pump, pcv system etc. running nicely.
Any help would be appreciated as I don't want to scrap the vehicle.

Post by **wizechatmgr** » 07 Oct 2017, 05:22

Maybe a cam/crank position sensor? (Just throwing an idea out there since it appears the majority are still asleep...)

Post by **jreed** » 07 Oct 2017, 05:46

+1 on above suggestion. When you check the camshaft position sensor, be sure to check the connector and wiring into the connector. Several people myself included have found that the connector crumbles with age. If it is a failed CPS, the fix is not expensive.
It might also be worth checking the distributor cap and rotor to make sure they are not worn out.

Post by **RickHaleParker** » 07 Oct 2017, 08:42

The ECM does not control the firing on a 97. The 97 ignition system is a simple distributor system. A independent repair garage or a good shade tree mechanic could diagnose and repair it economically. 1. camshaft position sensor 2. distributor cap 3. rotor is the first three things to check.

Post by **erikv11** » 07 Oct 2017, 09:54

Next in line after those is crank sensor and the coil.

Post by **precopster** » 07 Oct 2017, 10:43

Check for spark on the centre lead going to the middle of the distributor. If the rotor button is fried (it has an internal 2.2K ohm resistor). it can immediately cut spark to the engine.

jalwlb · Post by **jalwlb** » 08 Oct 2017, 23:01

The one time my 850 wouldn't start was because of a no spark condition. Long story short I found a 20 gauge multi strand wire with cracked insulation hiding disintegrated copper inside. After I replaced the bad copper wire the car started right up. If all of the above suggestions turn out good, I'd start inspecting every inch of wire for cracks or breaks.

SouthernMan · Post by **SouthernMan** » 12 Oct 2017, 17:23

Thanks all for the replies.
I am transporting the vehicle back home (5 hours away) and will then investigate further. The workshop that looked at the car are prediicting a dead ecu because there is no response from the obd2 port at all.
Just because it is a distributor/rotor ignition system it still relies on the cam and crank sensors for ignition and these are controlled by the ecu? Yes or no?
Many thanks.

Post by **RickHaleParker** » 12 Oct 2017, 23:48

"Just because it is a distributor/rotor ignition system it still relies on the cam and crank sensors for ignition and these are controlled by the ecu? Yes or no?"

In my previous post I meant to say, the ECM does not control the firing order on a 97. The ECM does decide when to fire.

Pages 12 & 13.

https://www.volvoclub.org.uk/tech/servi ... agrams.pdf

1998v70xcbill · Post by **1998v70xcbill** » 16 Oct 2017, 20:45

I just had the same problem on a 1998 v70. Ended up being coil. I checked cam, crank sensor and fuel pressure. All checked out. My secondary on coil was high resistance. (my problem Coil).
check my recent post for readings on cam and crank sensor.

Bill