1994 850 Ignition Coil overheat

osolanog850 · Post by **osolanog850** » 04 May 2015, 15:16

Hi Guys,
nice to say hello again, I have problems with my two Volvos (850 Both 1994). The first one: two cylinders with low compression,

The problems with the other car started with the camshaft position sensor, I changed, and then the car don't want to start, and I tried everything, but the problem that I have now, due to change the camshaft position sensor: is that the ignition coil is heating! I destroy two of them already, I sent the computer to review it and the computer its Ok, but I don't have, let say... spark in the cables that goes to the sparkplug, I change the crank speed sensor, buy another camshaft position sensor, sparkplug cables, ignition distribution rotor, and I have the same problem.... overheat in the ignition coil, and no spark in the sparkplug cable.

Post by **Ozark Lee** » 04 May 2015, 19:14

If the coils are burning up then the problem might be with the "power stage" that drives the coil. It is the trigger circuit that is bolted up next to the coil.

...Lee

Post by **precopster** » 05 May 2015, 05:03

I would have assumed that the OP is swappimg out the coil with the power stage as an assembly. Separating them is hard work as they are individually riveted to the coil frame assembly.

If this OP is separating them and JUST replacing the transformer I guess the results speak for themselves. ....

osolanog850 · Post by **osolanog850** » 05 May 2015, 13:58

Hi Guys,
thank you for your replies, like precpster said is a complete unit, does anyone have an electric diagram of the coil?

Regards
Oscar

osolanog850 · Post by **osolanog850** » 05 May 2015, 14:06

: Camshaft Position Sensor

: Ignition Coil

: Electric Problem (DIMM light)

Post by **precopster** » 05 May 2015, 14:46

When you fit the cam sesnor are you routing the wiring back through a plastic clip on the torque mount?

Most of these clips break off and the cam sensor lead then is allowed to be very close to the high tension leads coming off the distributor. The EMF generated by these leads into the cam sensor circuit COULD result in problems.

osolanog850 · Post by **osolanog850** » 05 May 2015, 15:05

Thank you, good tip! I'm not fixing the connector to that clip because I just put all together and do the testing, I will try later today,

I also change the crank speed sensor, do you think that this component could be damage by the ignition coil?

: Motor

Post by **cn90** » 05 May 2015, 17:05

"...overheated ignition coil + no spark".

Check your ground wires.

Also, check your voltage regulator.

Post by **precopster** » 06 May 2015, 00:38

Replace the rotor button. There is an inbuilt resistor which can break down and draw extra current.

You can't faultrace an ignition system without new components.

osolanog850 · Post by **osolanog850** » 06 May 2015, 07:46

Thank you guys!
I spoke with an electrician yesterday, he think that the problem is a ground wire... but we will see on Saturday.
Thank you guys again!

I will post the results
Oscar