2005 avalanche won't start

ok need some help here, my son was drive the avalanche the other day and the brake light came on then the engine died and wouldnt restart. we checked the fuel pump its working good but were getting no spark at the plugs and when you turn the key the engine turns over the first time but you have to wait a few minutes before it will turn over again. checked the code i i had one for bank 1 knock sensor (have had that for awhile its been intermittent). any help would be welcome

One thing you may want to look at is the condition of the battery.

i'll have him check it, its not that old he said before it died the only thing out of the ordinary was the brake light came on.

checked the battery it was good, we also pulled an injector plug and plugged in a nod light, no injector pulse.

Check fuses?

If the obvious stuff tests OK........

No spark or injector pulse sounds like faulty crank sensor.

To test, or replace, pretty sure starter has to come off.

checked all fuses they were good, replaced crank send still doesn't start, i think it could be the ecu.

It might be the ECM, but usually isn't.

Really, it could be anything.  That's why the solutions are usually found in the obvious stuff, which includes battery, fuses, wiring, & grounds.

Another consideration would be a Passlock problem; or, an issue with aftermarket security systems.  

Once the obvious is out of the way, then individual components can be considered.

In sensor land, the one for the crankshaft is probably at the top of the food chain; however, wouldn't want to swap it out, before proper testing (on the vehicle.)  

On top of that, odds are the engine won't start on an '05, without undergoing a relearn procedure using a proper scan tool (after a CKP sensor replacement.)

So, before things begin getting expensive, would start over from square one, & reconsider everything.

Here's a little something that may help diagnose the sensor that was replaced.  Unfortunately, you'd have to re-install it.

Troubleshoot My Vehicle

thanks for the info, we were checking all the writing in the engine bay and did notice onto in the MAF harness the block wire chaffed really bad and was shorting tin the chassis. i'll have to go back in a week or so to test for power at the crank sensor.

Sounds like you're heading in the right direction.

On an '05, there will be more of those situations.  Keep looking.

Have an '08, and "everything" is on my watch list.

For less than $30 a year, AllData might be a wise investment.  Not as good as the factory Helm manual, but the price is right.  Will help you locate where all the grounds are hiding.

Very important: 

Remove battery negative cable, before removing "any" engine or chassis grounds; or, you might fry something.

instro84 said:

thanks for the info, we were checking all the writing in the engine bay and did notice onto in the MAF harness the block wire chaffed really bad and was shorting tin the chassis. i'll have to go back in a week or so to test for power at the crank sensor.

Click to expand...

Reminds me of an issue I had with our 2000 vette that I rebuilt the engine about 18 months ago.  About this time last year I had it out on a decent winter day, hadn't driven it for a while and got on it and when the automatic did the 1-2 shift the engine cut out some for a couple of seconds.  I thought it had hit the rev limiter so dropped the 1-2 WOT shift about 100 rpm.  For a while that seemed to have taken care of it but then later in the spring it happened again at a local 1/8 mile dragstrip.  I dropped the shift point again but this time it happened again very soon.  I started thinking that maybe something else was going on and started thinking wiring as I had noticed on the track while logging some PCM data I lost a few seconds of data.  Basically went from about 50 mph and still WOT instantaneously to over 80 and slowing down at the end of the run.  After some inspecting I found some chaffing in a wire bundle that was going around from behind the engine to along the passenger side of the engine, right where the bundle turned the corner around the head.  The corner of the head had worked its way through the wiring sheaving and I could see where one wire was also exposed through its individual insulation.  Apparently the engine was rocking a bit during the hard shifts and causing a momentary short of that wire to the head.  I addressed that chaffing and knock on wood have been able to go back to shifting at around 7000 rpm on that LS1.