Fuel pressure drop

Duranali

New member
Jun 8, 2014
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I figured I would repost this as a new topic. I have an issue with my fuel temp sensor reading 32F all the time on my Edge CTS.

Still haven't found the fuel temp sensor but I've got a problem that may be related. It doesn't happen every time, but I am lose fuel rail pressure under full throttle. If I continue to hold the throttle, the pressure comes back and it accelerates again. It's never done it running the stock tune, but maybe I need to change the fuel filter? The truck is only a few months old though.

Before you say just take it to the dealer since it's under warranty, I'm not sure how to explain the fuel temp sensor issue w/I giving away the fact that I have a programmer.


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Last edited:

Burn Down

Hotrodder
Sep 14, 2008
7,092
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Boise Idaho
They will know it was programmed as soon as they hook up to it;) Sounds like your tune is draining the rail down. Do you have a lift pump or any other mods? How big is the tune?
 

Duranali

New member
Jun 8, 2014
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It's just the level 3 "performance" tune. I was told if you put it back to stock then they wouldn't be able to tell.


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durallymax

New member
Apr 26, 2008
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Under The Hood
I figured I would repost this as a new topic. I have an issue with my fuel temp sensor reading 32F all the time on my Edge CTS.

Still haven't found the fuel temp sensor but I've got a problem that may be related. It doesn't happen every time, but I am lose fuel rail pressure under full throttle. If I continue to hold the throttle, the pressure comes back and it accelerates again. It's never done it running the stock tune, but maybe I need to change the fuel filter? The truck is only a few months old though.

Before you say just take it to the dealer since it's under warranty, I'm not sure how to explain the fuel temp sensor issue w/I giving away the fact that I have a programmer.


Sent from my iPhone using Tapatalk


What year? Fuel temp sensor is in return line on drivers side of motor. Not sure on LML though.
 

ryan415

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Oct 24, 2012
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Your warranty is not necessarily void, it really depends on the dealer you go to. I replaced a tuned and deleted lml engine after the crank broke under warranty. GM determined the failure was not caused by the modifications, there for was still covered. Pretty cool if you ask me lol
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
It's just the level 3 "performance" tune. I was told if you put it back to stock then they wouldn't be able to tell.


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LML, LMM and I believe the LBZ has a tattle tale on how many times they have been programed, if it doesn't match what GM says, they know someone has been in there. Also the trans reads tq input and records the max number, if it doesn't match stock tq.... There are probably many ways they can tell.

Your dealer may or may not void your warranty...

What is the power rating on your level 3 tune? Do you have a lift pump?
 

durallymax

New member
Apr 26, 2008
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Under The Hood
Your dealer may or may not void your warranty...

What is the power rating on your level 3 tune? Do you have a lift pump?

Never understood this, I have never heard of a truck with a "Void Warranty". Just denied coverage on certain things.

Your warranty is not necessarily void, it really depends on the dealer you go to. I replaced a tuned and deleted lml engine after the crank broke under warranty. GM determined the failure was not caused by the modifications, there for was still covered. Pretty cool if you ask me lol

This is technically what GM's policy states, they are supposed to prove in multiple ways that the aftermarket part caused the failure. However its at the discretion of the tech and service writer. You could always protest it but that would be a long drawn out process.
 

ryan415

New member
Oct 24, 2012
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Yes, I know of a few dealers that refuse to work on any modifed vehicles. I had to take pictures of the ECM calibrations and maximum engine torque output off the tech 2 for them to decide cause of failure. Process took about a week before I got authorization to order a new engine.

Sorry for the derail.
 

kidturbo

Piston Tester
Jul 21, 2010
2,537
1,362
113
Somewhere On The Ohio
www.marinemods.us
Sites like this can be very useful at helping members sort the areas "cool" dealerships and techs from the "by the book" ones when it comes to certain modification.

Most of the good Dmax tech's I know are gear heads, and always up for a test drive in a hot ride... So if you take it in for regular oil changes and service, they ain't gonna rat out your mods unless ya have a rod hanging out the side at 10k miles or something.

:thumb: