1996 850 starting/ electrical ghost

hebronboat · Post by **hebronboat** » 10 Dec 2018, 14:43

Hi folks, I'm at the end of my proverbial rope! here goes, I turn the key to the on position, and all the usual dash lights come on ...except the cel. the car cranks , but doesn't start. If i wait 30 to45 minutes with the key on,.the cel illuminates and i can hear the idle air control valve activate, then the car starts and runs well! Sometimes the idle air control valve is heard, after the key is in the off position momentarily (the cel goes out after it starts.) What gives??

Post by **abscate** » 10 Dec 2018, 14:52

Sounds a bit like electrical part of ignition switch failing, about $50 fix

Diagnose by looking at 12 V on the IAC during the fault amd tracing back.

The CEL behavior is new and exciting, though.

hebronboat · Post by **hebronboat** » 10 Dec 2018, 15:13

Thanks for the tip, but if the switch is faulty, why would there be a waiting period??

Post by **abscate** » 10 Dec 2018, 18:02

Burned contacts, grease, intermittent spring pressure in switch. Lots of ways for this to fail

You can remove it and open it up and check it for just labor time of course.

Ozark lee did a great thread on this in this Forum

Post by **misha** » 10 Dec 2018, 18:59

If CEL is not appear when key is in pos.II along with all other lamps...and it's not burnt....that means that ecu is not getting power.
Could be ignition switch,but in this case all other lamps would not illuminate too.
I would check fuses first and main injection relay(grey one) on fan shroud under the hood for loose or corroded connections.
That grey relay is master(main) fuel injection relay and powers ecu.

You mentioned that iac valve is sometimes running when you turn the engine off...that would indicate that ignition switch is bad...like abscate mentioned.

Whatever you do....DON'T buy non oem part....it will fail fast and you'll be chasing your tail on this.

Post by **abscate** » 11 Dec 2018, 00:49

I think misha hit it correctly. The CEL is turned on through the ECU, while the dash lights are DIM (or equivalent on a 1996) so that's pointing to a problem in the relays and/or switch

Post by **Ozark Lee** » 11 Dec 2018, 08:13

If you are not hearing the IAC valve and the car won't start I would carefully check the master fuel system relay. That relay is not the fuel pump relay but rather the Gray colored relay on the left side of the fan shroud. That relay provides power to the IAC valve and the fuel injectors. The relay itself rarely fails but the wiring and the connector is highly exposed and subject to corrosion.

...Lee