2007 Denali wont start after cylinder head replacement

[CAPT75]

Hello all,
I'm incredibly stumped. After almost 4 months (due to lack of free time) of my truck sitting in the garage, i finally got it all together and the damn thing won't start. I discovered that cylinder 5 had zero compression. I pull the head and one of the valve seats is about 1/4" out of place. Take it to a machine shop to get it all fixed and cleaned up and put it back in. During the compression test I had thought my starter was bad so I put in a new one, turns out my old one was fine so after it sat on my garage floor for a month, I put the old one back in and returned the new one. I replaced the starter through the wheel well so maybe I damaged the ABS stuff while I was in there? That's the only time I touched the starter or wiring going to it. When I pulled the head I had to unplug the wiring to the upper intake manifold, coils, injectors, alternator etc. There was a braided metal strap attached to the head, assuming that was a ground? That's reattached. Didn't remove anything that wasn't absolutely necessary. So now everything is back together and I charged the battery (it was completely dead) I go to start it and I get absolutely nothing from the starter at all when I turn the key. No crank, no click, no sound, no nothing. On the dash there are three lights staying on, ABS, check engine, and the triangle with the car in it and wavy lines, assuming traction control? On the info screen its saying "Stabilitrak off, traction control off, park assist off, service suspension system". I can shift gears when the key is ON and I press the brake but there is no indicator line under the gears in the gauge cluster screen to tell me what gear I'm in. I'm getting power to accessories, but the door locks don't work, the dome lights don't come on, and the power running boards don't come down when I open the door. Scanned with an OBDII and I get no codes. What the heck is going on with this thing?!

 

[thompsoj22]

im just guessing, the fact that the starter does nothing, but small low current lights illuminate sounds like the battery to me. are you sure it is good, check the positive/ground connections. you are missing somthing simple somewhere.

 

[Big Mama]

What happens if you jump start it? The lights on the dash do sound like a wheel speed sensor may be unplugged. Usually the abs light sets off the traction control light too. Check your ground again and if all looks well eliminate the battery with a jump start or different one

 

[CAPT75]

The battery has been hooked up to a charger/jump box for two days, so it should have plenty of power. Could the inability to start have something to do with the security system? The security light comes on the dash when I first turn the key but turns off after about 5 sec. I’m out of town so I’ll check the grounds and speed sensor when I’m back home and report back. Could the ABS light issue also be causing the “service suspension” message on the gauge cluster screen? I also read somewhere that to feel the starter relay in the fuse box while someone turns the key to see if it clicks and that’ll tell you if it’s getting the ignition signal.

 

[petethepug]

Look for the ez stuff first. Plug /coil wires are placed correctly and 200% sure? Plug wires damaged or lost continuity during removal?

The dash indicator lights will do what your describing if one of the plug wires is left off. Obviously thats not the case so it leads to a concealed open in a coil or coil harness.


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[Big Mama]

But even with all that it should still turn over right? Yes the abs and suspension light and traction control lights can be related. Anxious to see what a good battery does. Check what it’s got before installing it. I just charged my bike battery overnight and it showed 13.8v not sure if a truck battery would be higher

 

[CAPT75]

Looks like it'll be on hold for a moment since over the weekend I rolled my ankle, strained my calf and hyperextended my leg I did check the starter relay in the fuse box and it's clicking when turning the key, so that should mean the relay and ignition switch are good, which only leaves the starter itself, right?

 

[Big Mama]

Good grief man. You’re having a tough go. You can always rap the starter with a hammer a few times to see if turns over. If so, no question

 

[CAPT75]

So my leg is finally healing to the point where I can get around decently enough, so I’m going to pull the starter tomorrow and get it tested to eliminate that. Does anyone know where I can get a schematic of the starting circuit? I was reading that the starting circuit may or may not pass through the BCM and/or PCM. If it is, and the starter is also fine, what could be causing the BCM/PCM to block the signal to the starter? The only wiring I removed and replaced during the cylinder head replacement were the spark plug wires and the upper harness to the upper intake manifold, coils, injectors, alternator, etc.

 

[wjburken]

When I replaced the Cam on my ‘07 XL Denali and got everything back together, I experienced the same thing. It ended up being the starter.

Can you check to see if you have voltage at the starter when you turn the key?

 

[Kraig]

If the battery was completely dead, it’s probably garbage. When you get your starter checked, get your battery checked too

 

[CAPT75]

I don’t have a voltage tester but I believe my neighbor does so I’ll see if I can get ahold of one. L When you had the same problem, did you also have any of the service/check engine lights/messages? I’m worried it may be a BCM/PCM issue only because I don’t get power to all my accessories (battery is fully charged) and the gear indicator light under PRND12 in the gauge cluster doesn’t illuminate either. I can shift into any of the gears, with the key in the on position, just no indicator light under which gear it’s in. The only other time I’ve seen it do that was when I was having issues with the MAF sensor, and it went into low power mode, but it never wouldn’t start.

 

[wjburken]

I did not have the warning lights as you describe. The BCM could very well be you issue but checking voltage at the starter is a cheap diagnostic step you can take. No voltage, it’s probably not your starter. If you have voltage, it warrants looking at the starter a little closer.

Once I got a good battery, the dash would light up like normal but when I turned the key to start, all I got was silence other than the relay for the starter clicking. I checked and was getting voltage to starter but no action. Took starter out and tested on bench in a vise with a set of jumper cables and still nothing. Took to Autozone and they said they confirmed it was dead.

I look back and laugh, but at the time I was going crazy. Imagine having everything but your block, pistons and crankshaft on tables in your garage to replace the camshaft and once you get everything put back together it doesn’t even turn over. First step in trouble shooting is look at what you just touched, which was basically everything! Once I went through and checked everything I could and confirmed with my brother-in-law, who helped, that everything we couldn’t easily check was done, I started chasing power.

Imagine my surprise, and eventual relief, when the starter, which had nothing to do what the vehicle was getting torn apart for, was the reason it would start. I thought for sure I jacked something up and was looking tearing things back apart.

 

[CAPT75]

Took the old starter to autozone to have it tested. I heard what sounded like spinning noise when they tested it, but they said it was bad. Got a new starter, put it in, exactly the same. No response from the starter, just silence and the relay clicking. Pretty sure the battery is garbage, had it on a trickle charger for a night and still barely got dash lights out of it. Jumped it off another truck and got all my dash lights, hvac fan, radio, but still no dashes illuminating under the gear indicator, can’t roll the windows up, power running boards don’t drop. The service engine light lights up but the obdII doesn’t read any codes. Traction control off, service stabilitrak, etc on the info center. I’m at a complete loss. I’m going to pull and check every single fuse in the truck to see if anything at all is bad. After that I have no ideas left!

 

[Doubeleive]

Took the old starter to autozone to have it tested. I heard what sounded like spinning noise when they tested it, but they said it was bad. Got a new starter, put it in, exactly the same. No response from the starter, just silence and the relay clicking. Pretty sure the battery is garbage, had it on a trickle charger for a night and still barely got dash lights out of it. Jumped it off another truck and got all my dash lights, hvac fan, radio, but still no dashes illuminating under the gear indicator, can’t roll the windows up, power running boards don’t drop. The service engine light lights up but the obdII doesn’t read any codes. Traction control off, service stabilitrak, etc on the info center. I’m at a complete loss. I’m going to pull and check every single fuse in the truck to see if anything at all is bad. After that I have no ideas left!

invest in a tech2 it will tell you all the little things that would be important right now, like is it sending a starter kill signal.
and just for fun, disconnect your battery then go turn the key to run/off a couple times, turn the light switch on/off a couple times, hit the brake pedal a couple times, then hook your battery back-up (preferably charged or new) and see if it will start then.

 

[CAPT75]

So it’s been a while, but I finally got the thing running. New battery, replaced all the relays in the starting circuit and reprogrammed the key. Although it’s still not without some issues. I’ve been driving it short distances periodically the last week or so. Still smells like burning oil, not sure if that’s the new gaskets or what. Figured excess spilt oil or other fluids that made a mess in the engine bay would’ve burnt off by now. My oil pressure is reading low for some reason, I’m maybe a quart low, but that shouldn’t be causing almost no oil pressure (that is if the gauge is accurate). Then a couple days ago the check engine light came back on and I noticed excess vibration coming and going while idling, like a shiver. Got the code read, and it’s a misfire on cylinder 5. Same cylinder that had the initial problem. It’s got new plugs and wires all around, I pulled the plug going to the coil as it was running and I still got spark arc’ing across, tells me the coil is good, and I compression tested it again and I have good compression in the cylinder. Not sure how to test the injector, but if it’s not the fuel injector, I’m not sure what else it could be? Especially since it’s only that cylinder. I thought maybe the gas could’ve gone bad since it sat for 8 months, but then wouldn’t that affect all the cylinders? If anyone has ideas, I’m all ears. Maybe something with the air/fuel mixture in the cylinder? I just want to get this thing running right so I can trade it in!

 

[Big Mama]

The fuel could certainly cause clogged injector. What was the code? There’s usually a little more info with a misfire code. Was the oil full or was it a quart low before the repair and was pressure low before too? If it was full how long did it take to lose a quart?

 

[CAPT75]

I never really knew what my oil pressure was before the repairs because my oil pressure sensing unit was bad, so I finally replaced that while I had the upper half of the engine torn down. I completely drained the oil and refilled it once it was reassembled. The code was a P0305, and there was another code I don’t remember off the top of my head. Something to do with the transmission fluid and low current. I’ll have to check my notes when I get back home, but if figured that a tranny code wouldn’t have anything to do with a cylinder specific misfire?

 

[CAPT75]

So I haven’t had a chance to get around to pulling the injector yet. I’ve been trying to at least run it for a few min each day to keep the battery charged and burn through the old fuel. I’m still above 3/4 of a tank. Oil pressure seems ok while I’m sitting there idling, a little below 40. I noticed when I start it, it runs smooth for about 30sec and then the misfire starts in. When I was installing the upper intake manifold, I accidently over torqued it. The specs called for an in/lbs torque wrench and I used a ft/lbs at the lowest setting because that’s all I had. As I was torquing it down, I heard the plastic pop. If something broke, or if the new gasket isn’t sealing right, that would cause a misfire correct? Throwing off the air/fuel mixture? I just figured if that was the case, it would affect more than just the one cylinder.

 

[bfourman]

Yes a cracked intake can cause a vacuum leak and a misfire.