dead 2003 malibu

[The_Jeff]

BIL's car. Conked out driving down the road. Was running fine before hand. 3100 V6, 120k mi.

A year ago, I bypassed the passlock system by cutting yellow wire while it was running. This cured a no-start. I am familiar with passlock operation and this does not smell like that. There is no (abnormal) security light; I did let it sit "on" for ten minutes anyway. There is a remote start and module to mimic passlock. Remote start Y's into the ign switch wiring; unplugging remote start harness still allows car to crank normally.

I hear the fuel pump priming. There's lots of fuel pressure. My OBDII scanner reports 200 RPM during cranking in the live data.

There's no spark; I put a timing light between a coil and plug wire. There's no power at any of the 4 pins of the ign module harness. There's no voltage at fuse 41, IGN MOD. All the "big" fuses are good as well as all the little underhood ones. With the key on and engine not running I hear a relay/ solenoid clicking regularly under the intake manifold; don't think it's purge valve. Normal?

I'm continuing to trace this, but any ideas?

 

[spasm3]

Would a crank position sensor failing cut out the fuel pump or would it interrupt power to ignition?

 

[The_Jeff]

CPS probably good b/c I saw cranking RPM.

Found a 3rd connector by the alternator (opposite side) that actually supplies power. Corroded and twisted. This is a typical GM connector that they use in "everything" and I witnessed another failure on a ABS sensor.

 

[Nyquist]

Do you have reference voltage for the ignition and other sensors?

 

[The_Jeff]

It's all fixed. Connector on ign module. The "four pin harness" I found earlier, despite having a red/black stripe wire, was not the power harness.

GM seems to have an engineer whose sole job is to make sure wiring is stretched extremely tight. This made repair difficult and also tugged on the affected connector, IMO chafing insulation, metal fatiguing, and breaking when it corroded.

Also fuse 41 was fine, I misdiagnosed. Red herring.

 

[GreeCguy]

Broken timing chain?

 

[GreeCguy]

Glad you found the problem -

 

[andyd]

Good job. Thats an easy auto-electrical fix. That is one of the attractions to the E28, enough length for repairs. I had to do a small amount of terminal repair on the Rat's primary circuits. I unhitched all sorts of stuff when I got it going. I thought putting it together was gonna be hard after having it unplugged for 3 months. It was idiot proofed though. All I had to do was to find the plug that the harness just barely reached.