Startup issues

[aaronbtb]

I am having some weird issues starting my trailblazer in the morning. It seems to act up when sitting longer. Almost all the time it starts up with a hesitation, sometimes it knocks really bad, sometimes the starter grinds after the hesitation. I got one video so far of the starter grind, but I'll keep recording it in the mornings so catch the knocking.

All coil packs replaced two years ago, spark plugs replaced 1 year ago. I just pulled all the plugs and everything was dry, no oil, plugs tips look white. Cleaned throttle body(battery unplugged for 20mins), mass, map sensor last week. CPAS was replaced 3 years ago. Just put castrol edge 5w30 in it. Starter is 3 years old. I don't think its a failing starter tho.

Once it's started its fine, still has lots of power.

I guess I should mention, I do have a pcm4less tune (back when they where pcm4less, not pcmofnc) I have it set to premium fuel, and thats what I have always used. There is currently a bottle of lucas fuel injector cleaner in the gas tank to see if that helps any.

 

[DAlastDON]

Does the starter grind when cranked via the key and not the remote start?

The knocking...Is it dieseling?

Dieseling or engine run-on is a condition that can occur in spark plug, gasoline powered internal combustion engines, whereby the engine keeps running for a short period after being turned off, due to fuel igniting without a spark.

 

[aaronbtb]

Its grinded with the key aswell. And no to dieseling

 

[Mooseman]

Is that by "flicking" the key or holding it in the start position? It sounds like it starts, stops and then the starter grinds trying to get back in sync with the flywheel to try again while it's still turning from the first attempt.

Sometimes mine fails to start when I just flick the key (flick the key, it tries to start and dies, starter not trying anymore by itself) and then I have to hold the key to get it to start. That's with both the I6 and V8.

 

[aaronbtb]

I stopped holding the key to get it to start because it grinds the starter just like in the clip. I have to "flick the key so autostart can takeover, same goes with the remote start.
It seems to me like it started starting rough when I put the longer belt back in to router around the air conditioner. I just put a shorter belt to bypass the ac again, to see if that helps any, but I doubt it.

 

[aaronbtb]

Could it be the starter is not engaging long enough to get the motor going? Maybe time for a new starter?

 

[Mooseman]

The flick start thing is actually the PCM that does that.

What brand starter did you put in it? I'm thinking maybe the overrun clutch (i.e. Bendix) is failing.

 

[aaronbtb]

I first bought a Dixie starter and it lasted 2 days, I returned it for a Wilson starter. The Wilson was a reman. Those are the only two starter brands I can get discounts on, everything else is to expensive.

 

[Mooseman]

Maybe there's a reason why they're on discount

 

[aaronbtb]

I got another video, you can hear it ticking for the first 24 seconds, then it stops and sounds fine after.

 

[aaronbtb]

I fixed the rough start/knocking, it had bad gas in it.

But I still have not fixed the startup grind. I replaced the starter and it still randomly grinds. What else could it be?

 

[djthumper]

Have you inspected the flywheel? Maybe there are some teeth messed up.

 

[aaronbtb]

No, but I did have it in a transmission shop was talking to the manager, he thinks it has something to do with my remote start, loose wire, or bad bypass module. I asked if it could be a broken tooth on the flywheel, he said if there was a broken tooth it wouldn't grind, it would just spin till it hits the next tooth.
Basically he thinks its a communication problem. Not the fly wheel.
I inspected all the wiring to my remote start and it looks ok, I soldered everything when I installed it. Unless the bypass is failing.

 

[djthumper]

Maybe you can capture some audio when it is doing it and post it up. Most just do a video...

 

[aaronbtb]

I posted a video of it in my very first post in this thread.
Today when I tried to start it with the key, the starter kicked on for a second then shut off. I shut the key off and tried to start it again and it fired right up. To me it seems like a voltage issue?

 

[Mooseman]

What if you hold the key to the start position? Both of mine do that occasionally to the point I usually hold the key each time.

 

[Sparky]

I watched/listened to that video in the first post several times, and this seems to be (to me) what it is doing:

1) cranks
2) fires, so stops cranking
3) sputters a second (for whatever reason)
4) starter gets cranking again (again, for whatever reason), but since the engine is still spinning it grinds until it actually engages properly
5) engine fires again and actually starts

It makes me want to blame the aftermarket remote start. Yes, even if using the key flick to start it as it is interfacing with that auto crank feature.

I may even go so far as to blame it if you're using the key and holding it until it starts. Reason is, the PCM will not let you spin the starter with the key when the engine is running (I tested this by accident lol). But if it doesn't start, it lets you crank immediately again even if the engine hasn't stopped spinning yet (again, I tested this by accident). So if the aftermarket thingy is interfering with the engine starting somehow it could in theory lead to this.

I don't know how that system is installed or how hard it is to temporarily disconnect it, but I'd be tempted to start (no pun intended) there and see if it stops the grinding at start with the key, both holding it and just flicking for auto start.

 

[djthumper]

I agree with what Sparky said.

 

[aaronbtb]

Thanks guys. I "think" I have found the issue. I have 2 batteries, one normal size redtop upfront and a huge yellowtop in the back for my subs. I have a isolator in between wired to the ignition. Its bin working for over a year without issue. But now the isolator is becoming slow and not kicking in immediatly, I think its kicking in while its starting OR disengaging while its starting. Either way I have it completely disconnected, just using one battery and so far 3 days without issue. Another week and a half will be the test. And if that isn't the issue, then I'll start dismantling the aftermarket starter, but that has worked fine for 7 years now.