I have a 1989 Buick Lesabre with 3.8. The ignition module was replaced a few years back (7-8) with a unit form Advance Auto. At the moment the car may or may not start, but when it does it will run for 32 seconds and shutdown. It may or may not re-start, but if it does start it will again die at 32 seconds. Prior to this there would be times when the car would not start but I could wiggle the wire harness going to the ignition module and it would then start. This was mostly after an attempted "warm" start.
My thoughts are there is a bad connection internally in the Ignition Module. But before I go replacing the module I'm trying to determine what the ignition pgm is looking for at 32 seconds after start so that I can check that component - any ideas?
Is the anti theft System activated when the engine shuts off?
The car does not have a factory anti-theft system. The security system I installed when my parents purchased the car in 1989 only disables the starting system.
When you mentioned those symptoms on an old GM 3800 engine, with a replaced ignition control module (ICM), my 1st thought was failing crankshaft position sensor (CPS) or corrosion in the plug/wires at the CPS connection.
Then you threw a fly into my ointment by saying that the vehicle would sometimes start after jiggling the wires at the ICM.
The crankshaft position sensor's wires are on that connection to the ICM, so now we're back at the ICM.
That said, 1st thoughts are like... well you know, everybody has one.
I'd want to rule out fuel/air starvation before getting into ignition issues.
You've made it easy. You know the car stalls 32 seconds after it starts.
First thing, remove and inspect your air filter and the air intake box where it sets for any obstructions.
Evict any rodents if found.
So just to make the test "legit", start the engine. Keep your foot off the accelerator pedal and let the idle air control valve (IAC) control the air flow into the intake manifold. We'll assume it stalls again around 32 seconds.
Next start: Start the engine but this time keep your foot on the accelerator pedal to maintain about 1,000+ rpms to remove the IAC valve from the equation. If it doesn't stall, then replace the IAC valve solenoid and clean the throttle body. If it stalls then it's probably not a air issue so move on to:
Next start: Remove the air intake hose and have an assistant hold the accelerator down again just above idle. When you're approaching the 30 second "mark" start spraying bursts of starter fluid into the intake and see if you can keep the engine running. If you can, there's a fuel delivery issue. If you can't it's time to look at the ignition side of the equation.
Be sure to look at the plugs and wire connections to the ICM and CPS for corrosion or damage first.
Here's a good link for walking you through, step by step, to test both the ICM and the CPS
https://easyautodiagnostics.com/gm/3.8L/ignition-module-and-crank-sensor-test-2
- A- WHITE wire.
- ECM control of Ignition Control Module (after the 400 RPMs and above are achieved).
- B- TAN with BLACK stripe wire.
- 5 Volt BYPASS from ECM for Ignition Timing Control.
- C- LIGHT BLUE with BLACK stripe wire.
- CRANK Position Signal to ECM.
- D- PURPLE with WHITE stripe wire.
- Fuel Injection Control Signal to ECM.
- E- WHITE wire.
- Instrument Panel Tachometer Signal.
- F- BLACK wire.
- CAM signal from the camshaft position (CMP) Sensor.
- G- YELLOW wire.
- CRANK (18X CKP) Signal from Crankshaft Position Sensor Assembly.
- H- LIGHT BLUE with WHITE wire.
- SYNC (3X CKP) Signal from Crankshaft Position Sensor Assembly.
- J- BROWN with WHITE stripe wire.
- CAM Signal from Camshaft Position (CMP) sensor.
- K- BLACK with WHITE stripe wire.
- Engine Ground (-).
- L- BLACK with RED stripe wire.
- Ground that ECM gets thru' the ignition control module.
- M- RED with BLACK stripe wire.
- CAM and CRANK Position Sensor Ground (-).
- N- WHITE with BLACK stripe wire.
- 12 Volts to CAM and CRANK Position Sensors.
- P- PINK wire.
- Fused 12 Volts power for Ignition Control Module.
