: 4 Engine Questions

09-28-09, 08:01 PM
I have four main questions about the Northstar (1996 Seville STS).

What type of ignition system does my car run -- where is the crank angle sensor (CAS) or distributor trigger wheel, and what type is it (Optical/LED Sensor? Hall Sensor? VR Sensor?)

How many teeth/windows/slots and what orientation does the CAS, crank trigger, and/or distributor wheel have? (any missing? all evenly spaced?)

Is there a distributor? Single/Multiple Coils? Coil on Plug?

Does this engine have a fast idle valve (IAC)? If so, how many wires are connected to it?

Thanks in advance.

09-28-09, 08:23 PM
Your engine uses a 4-coil waste spark system with standard emissions rated high tension wire to prevent spurious radiation of noise to onboard electronics: each coil fires 2 plugs at the same time; one plug on the power stroke, one plug on the corresponding exhaust stroke. The plug wire/coil orientation is critical to get the spark trigger at the correct stroke. Google "waste spark ignition". The two Hall crank angle sensors (CKP) are in the left side of the block, just right of the oil filter adapter, and in your engine they have the same part number. The reluctor wheel (trigger) is machined onto the crankshaft and has a series of asymmetrical teeth which act in conjunction with the Hall cam position sensor (CMP) to set timing. To figure this one out, you'll need a crank from your year engine. You cannot modify initial mechanical timing settings in a Northstar. The ICM receives ignition trigger pulses from the the PCM and sensors. There are NO moving parts save for the crank wheel. Fast Idle/IAC is a solenoid just behind and below the throttlebody and is set by engine temperature, rpm, and gear selection before idle stepdown and closed loop changeover.

For your particular ICM (Ignition Control Module) setup and possible changes contact Wester's Garage. (2000+ COP [Coil On Plug] need not apply)

Understand that these are simplified diagrams.........

09-28-09, 09:24 PM
Wow. You know your stuff.

Thank you for your response. I appreciate it.