Arcing ignition coil?

[rebecca8]

update........brand new Bosch ignition coil. Problem still occurs. I keep wanting to give up, but I noticed something today that I had not noticed before. Smoke, or steam......not really sure because of the cold.......coming from the front grill, possibly somewhere near the radiator fan. I had pulled a code 122 in A7 for temp. sensor interval too long. Someone told me that the ECT is bad. I really don't know the cooling system. Also have coolant in the oil, which I noticed about a month ago, but could've been there longer. Any other ideas anyone? I'm ready to sell the car, and it's probably something so simple. I've taken it to 3 different places, and already spent about $400 throwing parts at it. I feel so annoying and annoyed. The problems definitely seem to occur after or when it's raining or snowing. I've already checked the distributor cap, but will do it again. I'm getting so frustrated. It's been 4 months of this, and I need to find employment. Every time I think it's fixed, it's not. I don't know if I should take it to the dealer, or just get rid of it and ride the bus. Symptoms are misfire or stutter, after warm up and in damp weather.

[erikv11]

Sounds frustrating indeed. Now that you know the coil is good, checking the rest of the ignition system seems like the top priority. I'll try to help some, sorry if I ask redundant questions:

(1) You said the distributor cap is OK, have you looked at the plugs and the rotor?

(2) How bad is the stumble/misfire; sounds like so bad it won't hardly stay running? Does it have any codes right now?

BTW, the flashing up arrow can also come from a bad TPS (Throttle Position Sensor). If that is the case it will usually set a TPS code.

The steam from the front grill keep an eye on. I sort of suspect (hope) it is just from water touching the hot radiator but you never know. However I doubt it is related to the stutter.

A bad ECT, or a bad connection at the ECT, can cause a lot of weird stumble/misfire type problems.

(3) Get a good look at the connector to the ECT, what is the condition of the wires there at the connector?

[rebecca8]

Hello again. Thanks for trying to help. I have looked at the plugs and rotor, but a couple months ago. I can look again. The stumble/misfire is non-existent some days.......and esp. on days where I leave it at the shop.....they call me and say, "Sorry, but it's running perfectly, I can't find anything wrong with it." On rainy and more recently snowy days, it appears to always give me problems. The very first time this happened back in late September, it was raining, and every other day I remember this occuring has been rain/snow. During those days, it takes about 10 minutes for it start stumbling. I don't drive anywhere b/c I don't want to stall in the road, but I play with it a little in park, drive, or reverse to try to see what causes it to eventually stall, It's almost always when I press on the gas, and also when I shift into drive, or reverse. I can actually drive the car on dry days, it seems, and have absolutely no problems. Um, I haven't got any codes after I cleared them last, except for the PNP, but now the light is gone, and I cleared the codes again. The stumble starts out like a little hiccup or something for a couple minutes, then it gets really rough, where the car shakes for another few minutes, and then I press the gas some more, and it finally stalls out.

[rebecca8]

oh, and it will eventually restart, but I have to wait about 30 minutes. When I try to start it before waiting, I hear the starter, or flywheel....I don't know, spinning. It's also like the power is cutting in and out when trying to start it before I wait long enough.......don't know what that's about. It sounds like a dying battery, how it doesn't really turn over smoothly, but after that 30 minutes, it starts like nothing ever happened. I'm scratching my head raw over here.

[precopster]

Unlike most other cars the condition of the rotor in these Volvos is an unknown, regardless of how great it looks. We had a misfire in our '95 850 afew months ago (pretty bad and undrivable) and I was pulling my hair out when I tried a new rotor button. I also had the blue sparks at the coil around the body. I also bought a used Bosch coil.

The rotor buttons have an inbult resistor between the centre contact and the tip which is hidden by a resin like substance.

When they break down they really cause problems. Mine measured 2.5K ohms from centre to tip and this was the same as a new one.

[erikv11]

precopster knows his stuff, that is a good point about the rotor.

One other idea: these problems could also be due to a poor connection of either the positive cable from the battery, or one of the grounds. I wouldn't go chasing that right away, I think I would concentrate on the ignition stuff first, but keep that in mind too.

I am going to send you a PM here at the site.

[rebecca8]

So, I spent some time pondering and reading yesterday. I read somewhere that an ignition coil casing can crack if the plugs or a plug is damaged or plug wires, or any part of that system. The flow of electricity will travel back up to the coil if it can get there, and you'll see arcing due to it damaging the casing over a period of time. I looked up inexpensive plugs on autozone because I can't wait 5 days to get factory plugs from FCP. Anyway, I started the car yesterday, and it did the whole stumbling/misfire thing, so I headed out to Autozone once I got a ride. Stupid me, waited like 3 hours though to put the plugs in. I had other errands............Well, with the new $2.49 copper plugs, it started fine, and ran perfect. Now, I can't wait to see if it's OK when we get some wet weather around here. Also, what motivated me to try new plugs finally, despite having replaced them brand new 2 years ago, was that those new plugs cured a very similar problem I was having back then. The car was stalling in rain 2 years ago, so I did a full tune up. What I can't figure out is why they'd foul out after just 2 years. In December I pulled the plugs out, and cleaned them thinking it might help, but I kept dismissing the idea that they could've gone bad so fast. However, within one month, they've become coated in carbon again. I'm wondering if this could have something to do with the cracked coil, but I don't know. I drive very short trips esp. since I have been out of work..........I know that doesn't give the engine enough time to burn off deposits on the plugs. Also, I got a peek at the ECT. The wiring and connector seem to be OK. The temp gauge needle always slowly rises to the middle and never goes above that point, but you never know. That one code could have been, as you guys say, a legacy code..........Also, that is a really good point about the rotor. I've been swapping in and out new and old rotors to see if there was any difference...........nothing. I'm also wondering if the spark plugs could've have gone bad in 2 years because I really did have a bad MAF, or maybe because the catalytic converter was bad too. I had to get a new one last year because the pipe broke. They welded a "universal" cheap one on..........if there is such a thing. I can't believe the first place I took it to last year quoted $1400 for that job, and my car is a '94...........doesn't even need to go through emissions.......I told him that's how much I paid to buy the car, no thanks..........Anyway, does anyone know why spark plugs might go bad much much quicker than usual? This might help explain some things. Thanks for all your help.

[JDS60R]

You can get 2 proper oxy sensors delivered from Amazon for about $150 ( Bosch direct fit - most likely the cause here).
Copper core plugs if only used for short runs will last about 3 years.
The bad plugs don't cause the coil isolation to break down. Electricity will follow the easiest path so If there is a hole in the coil isolation and a ground nearby it will arc. A properly isolated coil with misfiring plugs should not arc like you saw it.

You can check the voltage output of your MAF per spec and see if you need a new one. If the cars was a 96 and some earlier you could could check to see if you have an OBD port. If so you can read the fuel trim and MAF values from the scanner instead of using a voltage meter and guessing on trim. I have never been clear on which pre 96 cars had OBD. My 95 850 non turbo had it.

[rebecca8]

K, now the flashing arrow is back. It didn't stall, but when the arrow came on, the idle was different. It was not too rough, only less smooth than it should be, but that's kinda how the stumbling starts out anyway. Except this time the rough idle didn't get so bad to where it stalls. Also, I drove it around the block a few times, and it's not in limp home mode (the speed from 1st-2nd-3rd gear picks up normally.) I checked all ports on the OBD. Only code is in A1-313, faulty signal from gear position sensor (PNP.) It is in the single digits here though........