Excessive fuel pressure while not running

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Katsslvn

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We have a 2007 gmc denali and it will display excessive fuel pressure 100 psi when truck/key is off. Mehcanic has supposably changed th fuel pump and module and vehicle wont start after driving for a few miles. Found if I release fuel pressure from fuel rail the vehicle will start. No codes showing. Anyone have any ideas?
 

Geotrash

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We have a 2007 gmc denali and it will display excessive fuel pressure 100 psi when truck/key is off. Mehcanic has supposably changed th fuel pump and module and vehicle wont start after driving for a few miles. Found if I release fuel pressure from fuel rail the vehicle will start. No codes showing. Anyone have any ideas?
This is one of the suspected causes of the hot no-start issue on the 2007 Denalis. A few folks have wrapped the fuel rail in heat tape to insulate it, but I suspect a poor quality aftermarket fuel pump as the root cause. Any idea what make/model of fuel pump they installed?

You can also likely get it to start by holding your foot to the floor while you crank (engages clear flood mode).
 

Fless

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Mehcanic has supposably changed th fuel pump and module and vehicle wont start after driving for a few miles.

If you have the invoice/receipt for the supposedly-changed parts, post up the part numbers that are on it, and any other identifying info (mfr?) for the parts. If you're not sure the mechanic changed the parts, then I'd recommend a frank discussion with him/her/they/it.
 
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Katsslvn

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We have a 2007 gmc denali and it will display excessive fuel pressure 100 psi when truck/key is off. Mehcanic has supposably changed th fuel pump and module and vehicle wont start after driving for a few miles. Found if I release fuel pressure from fuel rail the vehicle will start. No codes showing. Anyone have any ideas?
We changed the on start switch but still doing the problem
 

Geotrash

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We changed the on start switch but still doing the problem
In my opinion, you'd better served to stop throwing parts at it and let us help you with the diagnosis. We're quite familiar with these trucks and their common issues.

Question: it's not clear to me whether the fuel pump was replaced before the problem started or if the problem started first and the mechanic replaced the fuel pump to try and solve it. It matters so we can help you take the next steps. We're asking about the fuel pump itself because aftermarket pumps are notorious for causing problems like this on these trucks. If you can confirm that the pump was replaced with an OEM pump then we can move on to the next potential cause.

It's also possible that the high engine-off fuel pressure is a red herring. The usual cause of the hot no-start on the 2007's is the camshaft actuator. The problem with the camshaft actuator is in turn caused by low idle oil pressure because the actuator relies on oil pressure to control the angle of the camshaft. So sorting that out will be the next step.

Please respond to our questions when you can.
 
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