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Extended engine crank time on my 2017 6 liter


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So far it's intermittent which is why I don't want to be bothered with GM..... they are just going to say it's "normal" or "cannot replicate customer condition" unless I do the leg work for them.  So please refrain from the "take it in" comments...... thanks!

 

In recent times every once and a while the truck will crank a lot longer before starting.  Usually it's maybe 2 revolutions and it's running but then this sounds like the direct injected trucks and it will crank 6 or 8 times to get going.  I added fuel pressure to the scanner and it builds 550 kpa and holds it engine off but key on.  However taking it to start it will crank the longer duration before it lights off.  I thought it was only after sitting overnight but I just got it to do it with the truck just running, shut off and then restarted.  The scanner showed normal looking fuel pressure the entire time.  

 

Has anyone else had an issue or is there a TSB floating around for it?  

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Well if you have good fuel it must be a spark issue or fuel delivery issue.  How many miles are on the truck?  I had a similar issue when my fuel pump was putting out too much pressure.  Once it does start, does it sputter or does it light right off?

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Truck has under 20000 miles on it.  Fuel pressure drops on engine crank to around 400 kpa which is basically 60 lbs.  It fires normally just sometimes takes longer than others.  Talking with others they are mentioning the cam phaser being out of position on start... but that should set a code which i am not seeing.

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5 minutes ago, SierraHD17 said:

Truck has under 20000 miles on it.  Fuel pressure drops on engine crank to around 400 kpa which is basically 60 lbs.  It fires normally just sometimes takes longer than others.  Talking with others they are mentioning the cam phaser being out of position on start... but that should set a code which i am not seeing.

DId you go from 87 to E85 recently? only time my truck has acted like that was when I hadn't read the ethanol content correctly

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5 minutes ago, SierraHD17 said:

Truck runs 94 octane premium and is custom tuned.  Ethanol % is around 11% like it should be with that fuel.

 

gotcha, just a thought as mine had very similar symptoms when it calculated the % wrong

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It's not tune related considering i have rewrote it and it's been on the truck since I bought it 8 months ago.  It's like the ops at work blaming a plc program lol.... they don't just go bad.  Hasn't done it in a couple days now so who knows what it's problem is or was.

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If your truck is a 2017 l96 it is flex fuel correct? Read document ID #4518520 . The second paragraph details the fuel delivery system and yours does not have a fuel composition sensor.

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