Arcing ignition coil?

rebecca8 · Post by **rebecca8** » 22 Jan 2013, 19:07

I've been trying to figure out what's wrong with my '94 850 non-turbo for awhile now. Just went outside in this bitter cold to see if starts. It started, but of course the arrow starts flashing again. Last time it did this was also in single digit weather. I already know I got a PNP switch on it's way out, but that will have to wait a little longer if possible. Anyway, I brought a water spritzer with me. Gave the plug wires, and distributor cap a few squirts, and they appear to be fine. Gently misted the coil, and noticed tiny arcs of electricity along the sides of the coil case. I replaced the coil last year after my Bosch died out. I used an autozone part. I replaced it again (under warranty with autozone) a few months ago when I first started encountering stalling problems usually in rain or snowy weather. Could this be the problem I've been chasing for months? Does Volvo only like Bosch coils? I saved the original, and it looks a little different than the ones I've been getting from autozone.... more heavy duty. The arcs are about 3-4 mm in length on the sides of that plastic casing. How dangerous is this? I also noticed when I touched the metal part of the body of the car getting in and out, I got static shocks. Thanks to those who've been trying to help the past few months, I really have appreciated your input.

rebecca8 · Post by **rebecca8** » 22 Jan 2013, 20:33

I was just asking if there are supposed to be tiny sparks dancing around the outer casing of the coil. I'm learning as I go. I found the water idea online. Supposedly old school mechanics use it to find electrical "leaks."

Post by **JDS60R** » 22 Jan 2013, 21:08

The arcing should not be there. it is a sign that the casing has failed. The coil needs to be replaced. The car will work well with a quality part but there is not much in the way of quality out there. Be safe - buy Bosch -it got the car this far.
I am sure FCP has them along with many others. I still have one left that I paid $80 for when they were on sale.

I apologize for the previous posters comment. I will edit it.

nitehawk55 · Post by **nitehawk55** » 22 Jan 2013, 21:16

May not be the coil that's bad , it might just need new wire(s) and it could also be your spark plugs are ready to be replaced too (higher resistance will cause arcing). Sometimes just using some silicone grease in the wire boot will help stop arcing .
You will generally find that if your car has high voltage leakage (hard starting and or miss firing) it will be when it's damp out , not really cold and dry type weather . Yes you can test with water but it's not a true test that will determine anything is wrong under normal conditions .

rebecca8 · Post by **rebecca8** » 22 Jan 2013, 22:18

Thank you JD. I wasn't exactly sure if that poster was just trying to be funny or what. Like I said, I'm learning as I go. I did replace the plugs with genuine Volvo plugs, and the wires including ignition wire with Bougicord about 2 years ago. Also did the distributor cap and rotor at the same the time.
It has been missing, and it's almost always when it's raining or snowing. I've replaced the MAF sensor, fuel pump relay, had the throttle body cleaned, had some hoses replaced. Tried replacing the RPM sensor, but the symptoms persisted, so I put my old one back in. Checked codes, cleared codes, rechecked and found no faults. Since it hasn't rained or snowed here for a few weeks, I wanted to try to simulate damp weather. I didn't soak the coil, just misted it. I'm really glad to know that the arcing should not be there as I think I've finally found the problem. I hope if someone browses the website with a similar issue, they can check their coil and make sure it's Bosch. I'm going to order the coil from FCP, and will post back when I can confirm the issue has finally been resolved. Thanks to everyone who tried to help. I have a bunch of other posts on this same problem......

deltajets · Post by **deltajets** » 23 Jan 2013, 07:46

I just had a misfire problem in my car and what I found was excessive moisture in the distributor cap.Upon further investigation I discovered that the rear cam seal behind the ignition rotor had come out of its seat.I suspect that crankcase vapors were the cause of the condensation and a slight oil leak had plugged the drain hole for the distributor cap.After replacing the rear cam seals I have had no futher troubles.Your pnp switch can be repaired,its not a bad job I just did mine last month.Do a search on this site and you will find step by step directions.I did mine with the switch still plugged in.

rebecca8 · Post by **rebecca8** » 23 Jan 2013, 12:13

Cool, thanks for letting me know about the PNP switch repair, deltajets. I will try that when it warms up a little around here. I also think I will double check what you described. Thanks again.

Post by **cn90** » 23 Jan 2013, 12:56

Re ignition department....I recently tuned my 98 S70 GLT with 150K miles back to Stage zero, even with 0F, it starts in 1 shot.
Car runs so smooth my wife wonders if the car just came out of showroom lol.

Considering that the ignition system is important to get you to work etc., these are my observations:

1. The Ignition Coil: Bosch only and nothing else.
The ignition coil rarely ever goes out in the 850 series.
To check it, disconnect all wiring at ignition coil and read using Ohmmeter (Values are in Ohms).

850 series.........Primary Winding.......Secondary Winding
* Non-Turbo ............ 0.5 ....................8400
* Turbo .............. 0.5-1.5 ................ 8000-9000

2. The Spark Plug wires are relatively cheap $55 for Bougicord (autohausaz.com).
Old Bougicord with 150K had some minor cracks at the boots, occasionally had issues with damp weather, minor issues but bothersome.
New Bougicord: life is good.

3. Cap/Rotor are usually replaced every 50K-60K.
Cost is about $55 for both. Again Bosch Only!
If yours looks good then re-use them.
Otherwise replace them.
Check REAR Cam Seals too, if leaking replace them.

4. Spark Plugs: $2/each for Bosch copper.

I replaced items #2, #3 and #4. Car is smooth like butter.

rebecca8 · Post by **rebecca8** » 24 Jan 2013, 15:52

Thanks cn90 for all that info.

This may be a dumb question, but where do you put the leads from the ohmmeter on the coil? And what is primary winding and secondary winding? I will check it out of curiousity tomorrow before I remove it to return to autozone. I've already ordered the Bosch from FCP. Good to know that you confirm only Bosch.

Post by **cn90** » 24 Jan 2013, 17:45

rebecca8 wrote:...This may be a dumb question, but where do you put the leads from the ohmmeter on the coil?...

Below is info for ignition coil for Volvo 240/740 series but same idea:
http://www.vlvworld.com/indexframe.html ... 00_2_9.htm

PS: primary winding is where battery voltage is applied (12V). Secondary winding is where the voltage is stepped up all the way to some 48,000 Volts. An ignition coil is basically an electrical transformer. Pretty basic high-school physics stuff.

And if you follow my advice above (Bosch and Bougicord), you will never have to do this again! Your car will start in 1 shot.