2008 Tahoe no crank/starts and dies (solved)

[Woody258]

Good morning! Got in my Tahoe to head to work and this happened;

Starts, runs for a few seconds and dies
Repeated attempts and it either won't crank or cranks, starts and dies quickly

Battery good, lights bright, oil pressure looks fine when it does start. CEL came on a couple weeks ago but only get ERR when trying to read with an older code reader. Engine well maintained, no issues previously, ran good.

Has exhaust and a BB tune but nothing recently.

I immediately thought fuel problem but the crank, no crank confuses me. I had to take another car to work so I can't troubleshoot until tonight.

Any thoughts are appreciated.

 

[Geotrash]

Good morning! Got in my Tahoe to head to work and this happened;

Starts, runs for a few seconds and dies
Repeated attempts and it either won't crank or cranks, starts and dies quickly

Battery good, lights bright, oil pressure looks fine when it does start. CEL came on a couple weeks ago but only get ERR when trying to read with an older code reader. Engine well maintained, no issues previously, ran good.

Has exhaust and a BB tune but nothing recently.

I immediately thought fuel problem but the crank, no crank confuses me. I had to take another car to work so I can't troubleshoot until tonight.

Any thoughts are appreciated.

Year and mileage would help us help you. Need to get a decent code reader on there to see what's going on behind the CEL. Anything we say at this point would be guesswork because there are lots of things that can cause this from a bad fuel pump to a poor ignition coil ground, to a bad throttle body.

https://a.co/d/gy2CQny

 

[Woody258]

2008, 171k

Thanks

 

[Geotrash]

2008, 171k

Thanks

Thank you. You mentioned that on repeated attempts sometimes it won't crank. That's a smoking gun to me that you may have a bad ground in the engine compartment. These trucks have multiple ground points so the lights and electronics may stay on while a bad ground kills the engine. Without codes or a reader, I would start by loosening, cleaning and tightening the ground point on the front of the pax side cylinder head. Loosen, clean and reseat the battery terminals as well. The trucks are notorious for bad/weak grounds causing all kinds of problems, and the battery cables themselves corrode from the inside out. They look fine from the outside but are incapable of carrying sufficient load with internal corrosion. Seach "Big 3 upgrade" here and you'll find all kinds of good reading to help you sleep.

 

[Woody258]

Thank you. You mentioned that on repeated attempts sometimes it won't crank. That's a smoking gun to me that you may have a bad ground in the engine compartment. These trucks have multiple ground points so the lights and electronics may stay on while a bad ground kills the engine. Without codes or a reader, I would start by loosening, cleaning and tightening the ground point on the front of the pax side cylinder head. Loosen, clean and reseat the battery terminals as well. The trucks are notorious for bad/weak grounds causing all kinds of problems, and the battery cables themselves corrode from the inside out. They look fine from the outside but are incapable of carrying sufficient load with internal corrosion. Seach "Big 3 upgrade" here and you'll find all kinds of good reading to help you sleep.

Thank you! Gives me something to go on when I get home. It’s frustrating being at work and not able to work on it.

 

[stocksj]

Good morning! Got in my Tahoe to head to work and this happened;

Starts, runs for a few seconds and dies
Repeated attempts and it either won't crank or cranks, starts and dies quickly

Battery good, lights bright, oil pressure looks fine when it does start. CEL came on a couple weeks ago but only get ERR when trying to read with an older code reader. Engine well maintained, no issues previously, ran good.

Has exhaust and a BB tune but nothing recently.

I immediately thought fuel problem but the crank, no crank confuses me. I had to take another car to work so I can't troubleshoot until tonight.

Any thoughts are appreciated.

I had a similar issue and it was a crankshaft position sensor. You may also want to check your fuses in the engine compartment and make sure they are all reseated as they get loose.

 

[Woody258]

Thanks for the suggestion, making a list....

 

[Marky Dissod]

May not apply to your electronically signaled throttle, vs mine being a physically operated throttle ...
For the past two weeks, had what I THOUGHT was an electrical problem; my idle was living under 500RpM.
I was impressed, but did not realize it was a deeper problem.

One day, I went to start it after a short trip with lots of stop'n'go, and it tried to start but failed and died.
The extremely low idle was not allowing the battery to charge in stop'n'go traffic.
(Another reason why highway mileage is just better for any vehicle.)

In my case, the root problem was that the throttle body was dirtying up to the point that the idle was limbo-ing as low as 300RpM - yet it idled smooth enough that I did not recognize this as a root problem.
This eventually led to the battery being depleted by too much idling under 500RpM in too much stop'n'go traffic.

My next tune revision will raise the Drive-Idle to about 600RpM to keep the alternator excited.
A thorough throttle body cleaning and a brand new Idle Air Control motor were also called for.

PCV system needs a once-over. That's where all the stuff that accumulated on the throttle comes from.

 

[swathdiver]

I'm thinking fuel pump too. Get a modern code reader like this:

https://www.amazon.com/dp/B00W0SDLRY?psc=1&ref=ppx_yo2ov_dt_b_product_details

Get the Torque Pro App if you have an Android phone and set it up to read codes and fuel pressure.

 

[Woody258]

Thanks for jogging my memory. I do have torque pro that I had used on another car way back. I’ll connect it when I get home.