Check Engine Light on when Key is out. No start. Coil Melting.

qkraudgns32 · Post by **qkraudgns32** » 03 Feb 2019, 17:08

I have a 1995 Volvo 850 N/A Manual Transmission. It was driving fine 50 mph then the car clunked like I shifted bad, and then the engine died. I coasted in neutral to the side, then eventually got a tow. I tried to crank for about 2 minutes with gas pedal down too (not in one sitting, starter is still fine). The positive battery cable was pretty loose when I checked, it may have come off and on a few times. Maybe even frying some things?
Car is at a no start, but crank situation. Check Engine Light is on when car is off, key is out of ignition. It goes away when I have key on position 2. Strange.

OBD1 codes are:
A1: my box doesnt have the port for jumper to go into.
A2: 1-1-1 (how annoying)
A3: 422 213 214 141 142
A4: No blinks
A5: No blinks
A6: No blinks

Since then, I was looking around and saw my Ignition Coil was busted and had black stuff oozing out of it. Dont know if that is recent or always has been that way. Replaced it, tried jumping the car and sat there with the cables on while messing around with things. The replacement coil sizzled and busted in front of me. After cleaning my negative grounds, the wires and coil were still warm with 30 seconds of jumper cables on the battery. Is that normal? I'm afraid they will bust and melt again with prolonged driving.

Here is what I have done after reading around a bit:
1. Cleaned my Battery Posts with the wire thing, the terminals with the wire thing. No difference.
2. Cleaned the negative cable to body ground (in front of left headlight) and negative cable to block (under the starter/intake). No difference.
3. Removed negative battery cable overnight to reset ecu. No difference.
4. Replaced the camshaft and crankshaft position sensors. No difference.
5. Tried locking and unlocking the door 5 times for immobilizer reset. No difference.

Tomorrow, I plan on replacing the ECU. Is the Turbo ECU compatible with NA? There is a 1995 850 at the junkyard I can grab an ECU from. Maybe the ECU got fried when the positive cable made/lost contact quickly, and that was the clunking?

Also will try pulling the plugs and drying them out.

I'm pretty mechanically inclined, but I guess I can't figure this one out. Seems like an electrical problem. I dont know guys, any help would be appreciated.

Post by **misha** » 04 Feb 2019, 05:03

qkraudgns32 wrote: ↑03 Feb 2019, 17:08 ...Check Engine Light is on when car is off, key is out of ignition. It goes away when I have key on position 2...

Sounds like ignition lock is failed,but could be a combination of failed lock and something fried.
Check fuses first.

Sommerfeldt · Post by **Sommerfeldt** » 04 Feb 2019, 06:00

The ECU can fry coils, but it's super rare...
You can NOT use the turbo ECU unmodified on an N/A car. It might run, but it'll expect there to be a turbo, it's mapped and set up way differently, so I doubt it would drive. You might be able to reflash a turbo ECU with an N/A map, but it's not uncomplicated and you'd probably have to pay 20 euros or so to get a binary file that will fit, on top of the work and fabrication it takes to set up something that will actually flash the thing.

Best bet is to find an N/A and test if the ECU from that makes a difference.

- S

Post by **misha** » 04 Feb 2019, 06:36

If you're going with replacement ecu route...just make sure that replacement ecu have exactly the same Bosch numbers on it.
Being a '95 manual...do you have two ecu(s) in ecu box or just one?
Early models had separate ecu(s) for engine and ignition.

Post by **erikv11** » 04 Feb 2019, 09:03

I'd grab the electrical portion of the ignition switch from the 850 at the junkyard, and swap it in.

Post by **abscate** » 04 Feb 2019, 10:41

The positive battery cable was pretty loose when I checked, it may have come off and on a few times. Maybe even frying some things?

That is death to sensitive electronics. You want to proceed carefully as you may be in a thousand of dollars sink hole to diagnose and repair. The good news is things are not keyed to VIN in 1995 so you can at least swap parts for labor only.

qkraudgns32 · Post by **qkraudgns32** » 04 Feb 2019, 13:32

misha wrote: ↑04 Feb 2019, 05:03
qkraudgns32 wrote: ↑03 Feb 2019, 17:08 ...Check Engine Light is on when car is off, key is out of ignition. It goes away when I have key on position 2...
Sounds like ignition lock is failed,but could be a combination of failed lock and something fried.
Check fuses first.

Just checked all fuses. Not a single blown fuse.

Sommerfeldt wrote: ↑04 Feb 2019, 06:00 The ECU can fry coils, but it's super rare...
You can NOT use the turbo ECU unmodified on an N/A car. It might run, but it'll expect there to be a turbo, it's mapped and set up way differently, so I doubt it would drive. You might be able to reflash a turbo ECU with an N/A map, but it's not uncomplicated and you'd probably have to pay 20 euros or so to get a binary file that will fit, on top of the work and fabrication it takes to set up something that will actually flash the thing.

Best bet is to find an N/A and test if the ECU from that makes a difference.

- S

Ordered both ECU's for my car.

erikv11 wrote: ↑04 Feb 2019, 09:03 I'd grab the electrical portion of the ignition switch from the 850 at the junkyard, and swap it in.

Do you mean the part held in by two screws or the connector wires?

-----------------------------------------------
Thank you everyone for the suggestions.

Post by **erikv11** » 04 Feb 2019, 16:58

Held in by two screws, this one https://www.fcpeuro.com/products/volvo- ... 60-9447803

dj_v70 · Post by **dj_v70** » 05 Feb 2019, 19:40

“But the number one killer of ignition coils is voltage overload caused by bad spark plugs or plug wires.

If a spark plug or plug wire is open or has excessive resistance, the ignition coil's output voltage can rise to the point where it burns through the coil's internal insulation causing a short. The insulation in many coils can be damaged if output exceeds 35,000 volts. Once this happens, the coil's output voltage may drop causing ignition misfire when the engine is under load, or the coil may cease to put out any voltage preventing the engine from starting or running.”
https://www.aa1car.com/library/ignition_coils.htm

If positive terminal of coil has 12v when key is in position 2 and has 0v when key is removed, coil issue has nothing to do with ignition switch. I doubt ECU fried coil.

Post by **erikv11** » 06 Feb 2019, 00:14

I agree that the sequence of events doesn't argue strongly for a failed ignition switch, however ignition switch failure is super common on 850s, basically every one of them fails by about 200k (YMMV), and causes many bizarre and seemingly illogical electrical problems. Grab one from the junkyard just so you can rule it out.