Intermittent no crank, no start

[watuzi]

Hi guys, please help me out if you can. I have an intermittent no-start, no crank problem on my 2005 base RWD Tahoe with 250K+ miles. I have replaced both the battery and starter, but I still have the intermittent problem. Usually, it would only take me one to three turns before I could get her to start. But today, she really wouldn't start/crank no matter what. Out of desperation, I put the gear in neutral, and she started right away. Does it mean it's a faulty neutral safety switch or another problem altogether, like I'm guessing it might be the ignition switch? I hope someone can help me out here. Thanks.

 

[LsHart]

What is the key on engine off fuel pressure? And the key on engine running pressure? Theft light blinking? Cycling the key on and off twice, will it start and run? I know many questions. Lol gotta start somewhere

 

[LsHart]

My issue on my 04 5.3 hoe was my crank sensor

 

[watuzi]

Key on Engine off, the oil pressure is zero. When she's running, oil pressure is in the middle. Yes, usually it will take one or two tries, then she will start just fine. I'm just scared one of these days, she won't start anymore, and I'll be stranded.

 

[watuzi]

My issue on my 04 5.3 hoe was my crank sensor

Thanks, it's possible.

 

[mattbta]

If the camshaft position sensor is not an OEM, you may experience this problem. This is what my 2004 did on a shop unknown origin part:

I put an OEM one in and back to normal, after firing a massive parts cannon of fuel pump, pressure regulator, and doing the crank/cam correlation relearn. Oh well, pump should last another 170k.

Edit: did you also post on the GMT800 subreddit? I saw a similar post there today.

 

[Fless]

If it always turns over, but sometimes doesn't start, use a decent scanner on it to perform a CASE relearn to re-sync the cam and crank sensors.

Are you saying that it doesn't crank sometimes? Or it cranks (turns over) but doesn't start?

 

[LsHart]

Oem cam sensor was my only fix. Multiple ones from aftermarket places and the oe fixed it. Go figure. What I'm thinking is the OE has tighter spec range for the computer. Aftermarket ones the band is to wide.

 

[Doubeleive]

I have an intermittent no-start, no crank problem
no crank means no crank that has nothing to do with fuel pressure or crank/cam sensor
it's starter, starter cable, battery, ignition, park/nuetral, starter relay or something inbetween.
not too many other things that would prevent cranking

 

[LsHart]

So the issue is just no crank. No start leans to what has been said with sensors and fuel.

 

[LsHart]

Key on Engine off, the oil pressure is zero. When she's running, oil pressure is in the middle. Yes, usually it will take one or two tries, then she will start just fine. I'm just scared one of these days, she won't start anymore, and I'll be stranded.

Oil pressure should be zero with the engine off. Key on engine off fuel pressure.

 

[watuzi]

If it always turns over, but sometimes doesn't start, use a decent scanner on it to perform a CASE relearn to re-sync the cam and crank sensors.

Are you saying that it doesn't crank sometimes? Or it cranks (turns over) but doesn't start?

I have a no-start/no crank problem, meaning I turn the key to start the car, and nothing happens. The dash works (gauges work), the radio turns on, but the starter is not cranking to start. Also, no DTC.

 

[watuzi]

I have an intermittent no-start, no crank problem
no crank means no crank that has nothing to do with fuel pressure or crank/cam sensor
it's starter, starter cable, battery, ignition, park/nuetral, starter relay or something inbetween.
not too many other things that would prevent cranking

Thanks, I'm leaning towards a neutral safety switch cause I was able to start the car in Neutral.

 

[Doubeleive]

Thanks, I'm leaning towards a neutral safety switch cause I was able to start the car in Neutral.

a decent scanner like a tech2 should show you if it see's it is in park or not

 

[TJ Baker]

Thanks, I'm leaning towards a neutral safety switch cause I was able to start the car in Neutral

The most reliable check is to test for 12 volts at the starter relay from the park/neutral switch in the ignition switch RUN position.

There should be two different relay terminals at the starter relay that get 12 volts. One comes from the IGN A fuse and is "hot at all times".

The other comes from the IGN E fuse then through the Park Neutral switch to the starter relay. That one should have 12 volts positive when the key is at RUN and nothing when the key is at ACC or OFF.

Electrical Diagrams — 2005 GMC Yukon/Denali 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2005 GMC Yukon/Denali 4WD V8-5.3L VIN T.

charm.li

 

[Joseph Garcia]

I have a no-start/no crank problem, meaning I turn the key to start the car, and nothing happens. The dash works (gauges work), the radio turns on, but the starter is not cranking to start. Also, no DTC.

I had a similar issue on my 1997 Yukon (RIP). Occasionally, when I turned the key to start, I would get absolutely no response at all from the truck. Just like trying to start the truck without a battery connected. I'd try a few more times, and it would suddenly start.

Over time, the frequency of this issue increased, until I eventually got stranded in a shopping center parking lot. Turns out, it was the ignition that had failed in the start position. Replaced the ignition switch, and the issue was gone.

 

[watuzi]

I had a similar issue on my 1997 Yukon (RIP). Occasionally, when I turned the key to start, I would get absolutely no response at all from the truck. Just like trying to start the truck without a battery connected. I'd try a few more times, and it would suddenly start.

Over time, the frequency of this issue increased, until I eventually got stranded in a shopping center parking lot. Turns out, it was the ignition that had failed in the start position. Replaced the ignition switch, and the issue was gone.

Thanks for sharing your experience. It just might be the culprit.

 

[watuzi]

The most reliable check is to test for 12 volts at the starter relay from the park/neutral switch in the ignition switch RUN position.

There should be two different relay terminals at the starter relay that get 12 volts. One comes from the IGN A fuse and is "hot at all times".

The other comes from the IGN E fuse then through the Park Neutral switch to the starter relay. That one should have 12 volts positive when the key is at RUN and nothing when the key is at ACC or OFF.

Electrical Diagrams — 2005 GMC Yukon/Denali 4WD V8-5.3L VIN T Service Manual | Operation CHARM

Detailed repair manual for the 2005 GMC Yukon/Denali 4WD V8-5.3L VIN T.

charm.li

Ok, thanks so much. I will check the voltage at the starter

 

[Fless]

You could save a little legwork with a scanner that can read live data. Initially you can see what gear is selected, and if the "crank" request is being sent. Physical checks at the starter relay and the starter are also indicated.

 

[TJ Baker]

You could save a little legwork with a scanner that can read live data. Initially you can see what gear is selected, and if the "crank" request is being sent. Physical checks at the starter relay and the starter are also indicated.

Keep in mind though, if using a scanner you may be seeing the park indication from the transmission range switch set of contacts, A, B, C, & P. I don't think that output is involved in engaging the starter relay which is connected to other terminal pins at the Park Neutral switch assembly.