2001 Sonoma no crank

2001 Sonoma, 4.3 / stick.  195k.  All components mentioned below are OE except battery.

A couple weeks ago it did a weird no crank thing when I turned key to Start position. I tried removing and reinserting the key, no love. So I tried it again and it started right up. It’s done it a few more times since then. Each time, pushing in or pulling out on the key while turning has gotten it to start.  When it cranks, it cranks like fresh battery.  It has never slow-cranked..  Tonight, no amount of wiggling and jiggling the key will make it start.  I haven’t begun official diagnosis yet.  Things I need to check before ripping into switch R&R:

Is Battery really at 12+ Volts?

Can I bypass clutch safety switch?

If there’s a relay in start circuit, is it relaying?

Question for the hive:  is there a common failure mode which exhibits these symptoms? 

Thanks!

It sounds like a worn out ignition switch.

Don49 said:

It sounds like a worn out ignition switch.

I agree. If it is, you’ll definitely want to rent/buy both the steering wheel puller & the lock cylinder removal tools to do the job. 

Ignition switch FTW!  In this design, the ignition switch is a separate component from the key cylinder.  The switch slides up into place from below.  The key cyl turns a gear.  That gear meshes with a gear that protrudes slightly from the top of the switch.  Removal of steering wheel and lock cylinder not required.  I watched a video by “Main Street Auto Repair” once and that made me an expert.  Took me 2 hours from first tool out to last tool put away, including almost running over myself when I released the parking brake on my slightly sloped driveway wit the trans in neutral. Good times.

also, bought AC Delco switch for $58 on Amazon and picked up at a local locker facility. FLAPS had cheap Chinesium switch for $91.

OK, so the ignition switch didn't actually fix it.  it'll start fine several times over several days, then do the no-crank thing. the list below is probably not comprehensive, but OTTOMH i have had random, not consistent, success with the following:

i've tried turning the key back to ACC, then turning it to START, sometimes cranks and sometimes not.

one time i cycled the key from RUN to START and back 10-15 times and it did nothing nothing nothing then started.

i've tried all kinds of wiggling and jiggling the key.

i've stuck the key in gently and i've stuck it in hard.

i've held the ears on the cylinder as i've put the key in.

i've held the key in the START position when it didn't crank and one time it cranked after about 5 seconds.

i've left the key in RUN for 10 seconds and then turned it to START and it started.

i've jiggled the button on the key cylinder that allows it to be turned from OFF to LOCK and on the next key cycle it started.

anyone experienced similar and, if so, what fixed it for you?  i'm taking next week off work so i'll have plenty of time to tinker with it.

This thing doesn't have the key with the chip in it does it (PASSkey i think it was called).   Eventually the chip or the key cylinder wears and the resistor in the key doesn't contact well.  The bypass is to solder the appropriate resistor into the wiring harness, or get the BCM re-programmed to bypass the PASSkey security.  The key would look something like this if it has it.  (sorry for the huge image)

EDIT: My google-fu failed me, it's actually called VATS.  Looks like you can get new blanks off Ebay..

In reply to 06HHR :

thanks for the reply.  my key does not have resistor.  there is some kind of OE key detection security but i don't know how it works since the key doesn't have a resistor.  there are two very small electrical connections from the ignition switch harness to the lock cylinder housing.  one is the traditional "key in" circuit that enables the reminder buzzer / chime / warning, and the other is the key security anti-theft circuit.  i need to read up on that.

looking for a different thread, found this one and figured i'd update.  i'm an shiny happy person.  it needed a starter.

I didn't see this thread the first time through. I'm glad you got it fixed.

First step of diagnosis on one of those GMs is put a test light on the purple wire connection at the starter. If the light comes on when you turn the key to crank position you have ruled out the ignition switch, VATS, and clutch switch all in one step and narrowed it down to the starter itself. 

In reply to Cousin_Eddie (Forum Supporter) :

You're a genius Eddie. No idea why i never thought about this before. 

Dusterbd13-michael said:

In reply to Cousin_Eddie (Forum Supporter) :

You're a genius Eddie. No idea why i never thought about this before. 

You're giving me too much credit. Normal mechanic thought process there. I'm sure I learned it from some old guy when I was coming up. 

Dusterbd13-michael said:

In reply to Cousin_Eddie (Forum Supporter) :

You're a genius Eddie. No idea why i never thought about this before. 

uh, is it because you're *not* a genius?  and clearly neither am I.  ;-)