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Another Fuel Pressure question

3K views 34 replies 5 participants last post by  danmanswag 
#1 · (Edited)
2016 6.7 F250

Got a delete and 5 stage tune at GAW diesel...they came highly recommended (not sure about that)

Everything was good, no issues...took my truck in for oil change and fuel filter changes a few thousand miles later. 1 day after the service I get the fuel pressure light and start reading up on it. I called them up and explained and they tell me "bring it in, we'll check it out, might need a new fuel pump"

That really bothered me because they went right into saying I might need a new fuel pump instead of just saying they'll check it, maybe something is loose, etc. I decided not to do anything for a few thousand miles until I needed a couple new tires. Took it to my old mechanic (extremely trustworthy). He changed oil and both filters, checked everything out and said he didnt see any issues. Sure enough the light comes back on.

I've now driven almost 10k miles with this stupid light. My truck still has plenty of power..in the words of my mechanic "it's a rocket ship".

What is everybodys opinion? Should I be worried? Should I take it to the original place that did my delete and tune and possibly get bent over and raped? Being in Miami it's hard to trust ppl...GAW shop seems like good people, but it didn't sit well when they didn't offer to double check their work and went right in to an expensive repair.

TIA
 
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#2 ·
I would get it checked out pronto, shouldn't be driving it because for all you know you're starving the injectors for fuel. What is your actual fuel pressure? Could be as simple as the FRP sensor...

And who the hell is GAW Diesel
 
#8 ·
What did you tune the truck with? EZ Lynk? GtX? If it's an X4 I don't think you'll be able to see FRP sensor data so you'd need an OBD dongle and an app. The other 2 you can see it. But this "trusted" shop I'd certainly question, they should be able to check that with ease for you. I'd certainly think twice of running their tune from here on out.
 
#9 ·
That's what I was thinking....is it worth just going to another shop and going with a new tune? My mechanic couldn't get the sensor data because of the tune.

At this point it's either trust the original shop that did my delete and tune, or find another one in the area.
 
#10 ·
...what did you use to tune the truck with? You can check the data yourself.
 
#14 ·
Yeah lets not get into bad decisions lol...just want to resolve and then we can get into that stuff.

I dropped off truck for delete and tune. Tune is "allegedly" a 5 stage that has a knob under my steering wheel area. Knob has 1-5 turns for the different stages (allegedly).

Instagram gaw_diesel This is the place for reference...maybe you see something in the pictures that gives away info.
 
#15 ·
You might want to take the “highly recommended” out of that first post. The fact that they deleted and tuned your truck without giving you a tuner sucks.

You should’ve been given a tuner. That way you could buy tunes from anywhere if you didn’t like what they gave you. They’ll probably say it would cost more money, which it would, but it’s worth it. I just hope they sold you a good tune and not something they concocted. They might be the best tuners in the world. But I doubt it.
 
#16 ·
I stopped scrolling when I saw trucks with 24's and stretched tires.
 
#17 ·
I've now driven almost 10k miles with this stupid light.

Well that has already happened, not much else you can do.



With the concerns over the type of device used to tune the truck, you need that answer first and foremost. If GAW isn't going to give you a physical device your options are going to be limited in the future. Nice way to keep you captive as a customer.



To the Low Pressure "light" seems odd it popped up long after the initial work...yet it happened after fuel filter changes. Hmmmm.....You should be able to cycle the key to ON, if there's no noise from the fuel system that resolves the "air in the system" concern....I'd say it's a sensor issue. If you hear pump noise, you need to go thru the key ON position purge to run the lower pump till you don't hear any noise. Most will say 6x but I have gone as much as 10-12x before the noise has decreased to an acceptable level. IF by some chance the noise is still present after 10-12x key cycles you need to check the filter connections on the upper filter, then check the lower housing is sealed properly. People report the lower housing o-ring will roll over, or not seal properly. At the end of all this air is a M-Fer to the 6.7L fuel system. Adding another wrench is the truck runs fine by your accounts.





At this point we can sling poo into the fan till the end of the day....you need to get a no BS shop to hook up and see what's what with the system info. Especially to find fuel pressure readings or any soft codes on the PCM.
 
#19 · (Edited)
Appreciate the info. I'll check a few things out when I get my truck back later after work.

They did offer a device but insisted it was unnecessary and expensive. In hindsight, I should've just gotten it...but as you can see, I'm no expert....I thought I was taking advice from the "experts".

I tried to listen to the "pump noise" when I read some threads months ago or anything else and didn't notice anything...at the same time, I'm not sure what I was listening for exactly.

I'll start from square 1 again and report back here later....appreciate the help.

/ as you can see, I'm not much of a diesel mechanic....give me an outboard and I'll pull the lower unit, change oils, filters, pumps and tstats.
 
#20 ·
So what did they give as an "expensive" device price? What work was done? What did they charge you for all the work??


I'm not trying to bust your chops, if you want an outside opinion to consider before you want to recommend this shop to anyone else.
 
#21 ·
I want to say it was like $300-$500...honestly I don't remember. I actually wanted it, and they talked me out of it. If I recall, it was around $1,500 for the delete and tune. Once again, I dont remember as it's been a while. It was never about the money...I just wanted good work done.

I am not recommending them, but rather they were recommended by a few guys I spoke to.

Let's see what happens and if I end up taking it back there or to another shop...If I can find a good one.
 
#22 ·
I'm willing to bet they bought tunes for his truck through one of the few that tune 6.7's, charged him an extra 300-500 and said it was their tune. Then kept the device.
 
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#25 ·
Ok, so I got my truck back...no light for fuel pressure yet after about 4 miles of driving. I turned the key to on position and heard the pump. I let it run till it stopped. I then turned the key off and then back to on again and didn’t hear it again. I did this about 6 times and it never came back on.

Just drove the truck about 1 more mile and turned it off. Put the key back to on position and I hear it again....but it’s not stopping after 2 minutes straight
 
#26 ·
Do you mean you cycled the key to On, let it run till it stopped (after 30 seconds), then cycled the key off, then cycled to ON at least 4x.....for a total of two minutes of run time??


The lower fuel pump will only run for 30 seconds at a time when cycled to ON.



After all that if you still hear noise, I'd suggest checking the filter connections and housing.
 
#27 ·
Was on my phone so wasn't too clear...

Cycled key to on and let it run till it stopped (30 seconds)...did this at least 4x and didnt hear anything.

Went to the gym and when I got there I did it again...this time it ran for a long time (I should've timed it, but felt like 2 min).


Let's fast forward to this morning....before leaving to work I go through this again.

Key to on position - 30 seconds of it running and then it stopped. I did this 5x and each time it ran for 28 seconds exactly. I had to eventually stop because I needed to leave to work.

The fact that this is happening...does that mean I have air in the system? Like you mentioned, possibly the filter connections or housing?
 
#31 ·
If you find that one or both of your filter housings are loose in some way, I wouldn't take my truck back to the "highly recommended" shop again, if they couldn't discover either one was loose.
 
#32 ·
@joebuck and @jman37 have you covered and have awesome advice as well. Check the connections on the filters to be sure.



As long as the Low Pressure warning is gone just pay attention to the pump noise. It may come and go. We do want it to stay away of course. If one day it's gone, another day it's there, then goes away. My experiences say that's a upper or lower connection issue that is letting in air. Just keep it in mind.

I almost always get in cycle the key to On, fasten the seat belt, lower the window, and listen. Since the pump will only run for 30secs I give it 15 or so.....lots of noise....cycle the key again once the pump shuts down. No noise....start the motor.


BTW you are running what is most commonly referred to as a SOTF (Shift On The Fly) 5 position switch. Changing the position while driving can be accomplished with whatever setting you prefer. My advice: Find a happy spot and leave it alone.
 
#33 ·
Just an update...don't want to ask for help and then just leave ya'll after helping me out.

Haven't had time to get dirty and check out the filters, but I will this weekend. Do you know what specific tools I need? (specific size socket wrench?)

I've been letting the it pump before starting my truck and my light has only turned on 1 or 2 times so far this week since I've gotten the truck back. That would lead me to believe that it's definitely air like you mentioned.
 
#35 ·
Haven't followed up, been slammed...especially this week with this hurricane!

So I removed and inspected everything. Put filters back on securely. I let it prime doing the whole "key on for 30 seconds thing" countless times. I have not had a light on for almost 2 weeks now. Truck seems fine. I'm going to assume I had air in their and was causing the pressure to drop and the light turn on.

Thanks again everybody for their help with this!

/ side note - most gas stations are out of gas or have massive line down here. It's nice to roll into a gas station and its empty because they have no gas, ONLY DIESEL LOL. Filled up my tank this morning without waiting while all the suckers are scrambling and waiting in 1 hour lines
 
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