Motor refresh complete, now no crank, no start

[nadthomas]

So, for anyone that has been follow my build thread, I pulled the motor out of my 2007 Yukon Denali with 192k miles over the summer to replace the oil pump, refresh all of the gaskets, fix the broken exhaust manifold bolts, and address a handful of other things while also doing a lot of cleaning and degreasing. I also pulled the transmission valve body to inspect it and to check for worn check balls. I finally got everything back together over the weekend that is needed to fire her up. I reconnected the battery, and go to start it up.

The first thing I did after turning the ignition to on, was cycle the gear selector to make sure the vehicle was in park. I only drove this vehicle occasionally for the few months I owned, so my memory could be fuzzy on how a few things work on this vehicle. I noticed the the gear indicator on the dash did not change at all as I moved the shift lever. Shouldn't there be a line or some sort of indication of gear change even with just the ignition turned to on?

Setting that aside for the moment, I proceeded forward and turned the key to start. The radio and dash reset, so I assume the battery was weak after sitting for 4 months, and apparently at one point I popped the rear glass so I'm not sure how long the battery was connected with glass popped. So I could have drained the battery pretty good. Off to Autozone to have them test and charge the battery. They said the battery tested good, and charged it for about 1.5 hours. I dropped it back into the Denali, test the voltage which read 12.3V on my multi-meter. Attempted to start, and got the same thing. No start, no crank, gauge cluster blanks while the key is in the start position and resets when release. So, I started to research and diagnose.

When the key is turn on, I believe I hear the fuel pump prime, but its kind of hard to tell since there are several things that make soft buzzing and humming noises when you turn the key to on.

I don't believe its a key transponder issue with the Passkey III security system. The light for that on the dash lights up when the ignition is turned to the on position, and then turns off after a few seconds.

The starter is new, and when put a screwdriver across the terminals it certainly spins.

One thing that leads me to believe I have an issue with the computer or communication issue with the computer is that the fuel gauge never moves and is on Empty.

Following some of the diagnostic test from this video.

With the ignition on, I tested with a test light, and have power across Fuse 56, 12, and 4. I also have 5V reference on both the MAP and MAF.

So, I'm a bit stuck at the moment. I bought a trickle charger to ensure the battery is fully charged, and I bought the VXDiag VCX Nano GDS2 which should give me a Tech2 virtual machine that I can run from a laptop. I'm hoping once I have that I will have a lot better understand of what the truck can and cannot talk to. I'm open to any thoughts or inputs, or even steps I should take once I have access to Tech2.

 

[Rocket Man]

Sounds like it might be a ground issue. Are you sure you reconnected all the grounds, especially from the block to the frame?

 

[kbuskill]

It sounds almost like the truck doesn't know it's in park.

 

[nadthomas]

Sounds like it might be a ground issue. Are you sure you reconnected all the grounds, especially from the block to the frame?

Off the top of my head I can think of 4 ground wires on the block. Although the only one that I'm confident where the other end attaches is the one on the firewall near the brake booster. I don't recall removing any from the frame, but its possible I may have removed one or two from the frame while I was cleaning and painting things. I will check those tonight.

Let me make sure I have them all

1. Driver side Head to Firewall
2. Driver side below the exhaust manifold to Frame(?)
3. Passenger side head to Frame(?)
4. Smaller gauge wire also on passenger side head to (?).

 

[nadthomas]

It sounds almost like the truck doesn't know it's in park.

I was wondering if that was a possibility as well. If so, what tells the computer its in park?

 

[camaroz2887]

Had almost the exact same issues with an 03 after an engine swap. Turned out to be the battery/ground cables on the starter. I think a park/neutral safety switch or something with trans linkage could b possible too. I Didn’t have the shift issues tho.

 

[kbuskill]

I was wondering if that was a possibility as well. If so, what tells the computer its in park?

Park/neutral position switch is on the side of the transmission where the shift linkage connects.

Try this...

Open the hood and remove the cover from the underhood fuse panel. Place your hand on the Starter relay and have someone else turn the key to start. You should feel the relay click each time the key is turned to the start position.

If the relay clicks, the ignition switch, neutral safety switch and all wiring is good up to that point.

I'm thinking maybe when you dropped the transmission pan to check your balls that perhaps you didn't plug it back in or somehow damaged the wiring.

Not sure if you removed it to drop the pan or just pried it out of the way, which is common.

 

[nadthomas]

Hmmm, I didn't have to disconnect or move anything to drop the pan. Now, to remove the valve body there was clearly connections to the gear shift selector, and an electrical connection for the TCM. I think this may have been where I screwed up. After pulling the white plastic tab to release the TCM electrical connections the valve body slide right out. So, for the re-install I just slide the valve body back in making sure to first align the TCM's electrical connection, and push back in the white tab.

According to this video the connection is much different then what I thought I was working with.

 

[Scottydoggs]

years ago my 03 sierra did something like this out of the blue, turn key and the gear indicator just went to 1, of course it wont start then, was under warranty so the dealer towed it in, iirc they said it needed the pcm reflashed to a newer os.

 

[Rocket Man]

Hmmm, I didn't have to disconnect or move anything to drop the pan. Now, to remove the valve body there was clearly connections to the gear shift selector, and an electrical connection for the TCM. I think this may have been where I screwed up. After pulling the white plastic tab to release the TCM electrical connections the valve body slide right out. So, for the re-install I just slide the valve body back in making sure to first align the TCM's electrical connection, and push back in the white tab.

According to this video the connection is much different then what I thought I was working with.

The symptom of no gear indicator position is what I had on my 08 Silvy when I accidentally removed one of the TCM fuses and the trans went into limp mode. The gear position indicators went out. I'll bet that connector you messed with isn't plugged in correctly and like was mentioned earlier, it needs to know it's in park before it will start.

 

[nadthomas]

As much as I hate the idea of dropping the trans pan again (why didn't GM put a drain plug on these), I think we are onto something. Hopefully, my wife and kid will give me enough time to work on this tonight.

 

[Rocket Man]

As much as I hate the idea of dropping the trans pan again (why didn't GM put a drain plug on these), I think we are onto something. Hopefully, my wife and kid will give me enough time to work on this tonight.

By chance did you change the filter while the pan was off? If not, now’s the time.

 

[kbuskill]

I forgot you have the 6L80 because its a Denali.

I was thinking '07 = 4L60... in which case the gear position switch is external.

Sorry for the confusion but sounds like you are on the right track.

 

[Doubeleive]

I had some body work done this summer and the body guy ran into a no start, I went over there to see what they had done and saw one of the fuse box handles was not in position, apparently they had pulled the handle to remove a bolt for the quarter panel, after messing with the fuse box a few times lifting it and putting it back down and banging on the fuse box it finally went back to starting, everything else was working just no start. so my point is if you moved the fuse box at all you may want to check that out also but I would say only if it is was moved otherwise it could be compounding the problem

 

[nadthomas]

By chance did you change the filter while the pan was off? If not, now’s the time.

That was the original reason I was diving in there. Drain the fluid and replace the filter. I figured while I was there I would also inspect the valve body.

 

[nadthomas]

I had some body work done this summer and the body guy ran into a no start, I went over there to see what they had done and saw one of the fuse box handles was not in position, apparently they had pulled the handle to remove a bolt for the quarter panel, after messing with the fuse box a few times lifting it and putting it back down and banging on the fuse box it finally went back to starting, everything else was working just no start. so my point is if you moved the fuse box at all you may want to check that out also but I would say only if it is was moved otherwise it could be compounding the problem

One problem solved. Tried this as one of the first things I did this evening, but apparently wasn't aggressive enough with it. So, I dropped the exhaust, drained the trans fluid, dropped the pan, pulled the valvebody and fiddled with it and its connection for over an hour with no improvement. So I came back to review this thread. Decided to get more aggressive with pushing the fuse box back in, and bam. Gear selection is now displayed on the dash, but still no start, no crank.

The Tech2 device should arrive tomorrow, hopefully that will shed more light on things.

 

[Doubeleive]

One problem solved. Tried this as one of the first things I did this evening, but apparently wasn't aggressive enough with it. So, I dropped the exhaust, drained the trans fluid, dropped the pan, pulled the valvebody and fiddled with it and its connection for over an hour with no improvement. So I came back to review this thread. Decided to get more aggressive with pushing the fuse box back in, and bam. Gear selection is now displayed on the dash, but still no start, no crank.

The Tech2 device should arrive tomorrow, hopefully that will shed more light on things.

you might want to keep trying I had to mess with mine a few times as well (but) I knew that was it because that was the only thing they touched

 

[nadthomas]

you might want to keep trying I had to mess with mine a few times as well (but) I knew that was it because that was the only thing they touched

Oh I did, but I have more variables going on so I think there is probably something else going on as well.

It looks like my VCX Nano/Tech2 won't arrive until Thursday now. So, I have one more night to try other things. I feel like the gas gauge not registering anything is still a key indicator to this problem.

 

[kbuskill]

Oh I did, but I have more variables going on so I think there is probably something else going on as well.

It looks like my VCX Nano/Tech2 won't arrive until Thursday now. So, I have one more night to try other things. I feel like the gas gauge not registering anything is still a key indicator to this problem.

Not trying to hijack your thread but I am curious about the "VXDiag VCX Nano GDS2" you mentioned earlier.

When you purchase that does it come with all the software and everything you need to make it work or do you have to purchase software separately???

 

[nadthomas]

Not trying to hijack your thread but I am curious about the "VXDiag VCX Nano GDS2" you mentioned earlier.

When you purchase that does it come with all the software and everything you need to make it work or do you have to purchase software separately???

Its supposed to come with both GM's GDS2 software, and a virtual machine for WinTech2. From what I was reading WinTech2 does not support writing to the controllers, so I won't be able to reprogram anything, but I believe you also need some sort of subscription from GM to program controllers anyways. It should do pretty much everything else from what I understand.