The Diesel Stop banner
1 - 20 of 46 Posts

·
Registered
Joined
·
392 Posts
Discussion Starter · #1 ·
My question is in the last paragraph. This middle section is my back story. Thanks in advance for those who have the patience for me.
Ok, so I need some help understanding afr for a diesel engine
I have what appears to be low boost and moderately high egts. I have replaced and properly adjusted my wastegate pressurized my intake and found no leakes. Have no soot on my exaust pipes and my turbo spins freely with no side to side play and all the vanes are there and not bent or missing.
Truck starts fine drives mostly fine just seems to fall on its face during wot. It will get most of the way through the gear and right before it shifts it feels like it looses its umph. I have mated the go pedal for 3 minuites and the rpms do not hold as steady. It will fluctuate by about a 100 rpm every so often.
I haven't put a fuel pressure gauge on yet but I am going to.
My question is. How does low fuel pressure create a night egt situation. My (flawed) logic says low fuel pressure lower egts because less fuel with the air? Am I just completely wrong here?
 

·
Premium Member
Joined
·
7,934 Posts
Fuel acts as a coolant to a level.


If you have fade out in power and the tach needle hunts around when trying to hold it steady, it's in your fuel supply or in the case of aeration, in the fuel itself.

Check pressure and flow. Give it an alternate source to drink from at the pump to try to root out aeration.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #3 ·
I feel like my in tank feet are cracked. Because at about a 1/4 tank it really behind to run funny. Anything above she behaves as it is supposed to. So my fuel is most likely aerting? I saw in another post that that can cause the injectors to make more noise. I do occasionally hear the engine making a metal on metal clanking sound. So that could be the injectors, yes?
 

·
Registered
Joined
·
628 Posts
Look up guzzle hutch mod. It'll fix all your in tank woes. Also a good time to consider adding a spin on filter and helper pump.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #5 ·
How much can a helper pump actually benefit? Wllouldnt just upping the fuel pressure do more? Or does a helper pump up the pressure too?
 

·
Premium Member
Joined
·
7,934 Posts
Yeah I don't subscribe to them on a pick up as the fuel line is not that long.
The stock pump will hold a prime leading up to it.
I do recommend removing the tank filters and installing a big fuel filter water separator spin on filter with a drain peacock in bottom of it, mounted to the inside of frame before the pump.
 

·
Premium Member
Joined
·
3,754 Posts
Here's the post filter / water separator that's fitted on my truck , this same filter can also be fitted to the pre side.
Have you a chip fitted and what brand?
 

Attachments

·
Registered
Joined
·
392 Posts
Discussion Starter · #8 ·
I do have a chip. It's a dp Tuner. I have all his tow tunes and run with his 80hp daily tune. I do also have his 120 horse tune as well but only have ran it once so far as my boost is slow to build and it keeps the egts way high.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #9 ·
I think I need to be prepared to clean my fuel tank as well. Before my injectors went I was getting a lot of oil in my fuel system. Haven't checked it lately but my filters are staying black.
 

·
Registered
Joined
·
628 Posts
The pre-pump is there to protect the main pump. It'd a whole lot cheaper. Is it necessary? Probably not. But in my experience it does help stabilize your fuel pressure.
 

·
Premium Member
Joined
·
3,754 Posts
I think I need to be prepared to clean my fuel tank as well. Before my injectors went I was getting a lot of oil in my fuel system. Haven't checked it lately but my filters are staying black.
I would do the hutch mod as Gator5713 suggested, then test.
If the fuel is showing black now you have some problems with inj O-rings maybe.

Dp - chip will possibly give you a slightly higher egt's , but you need to get to the source of the low boost.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #12 ·
I don't know if its still turning black. But it was after I re oring the injectors. I figured it's built up in the tank still. I have only been through 2 fuel filters since I have repaired my injectors.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #13 ·
Is there a chart or something that's show rpm to speed to boost? I realize you have to work these engines to make boost but maybe at least a general idea? I will be doing the hutch mod. And will harpon it since it will be down . maybe check the auction line for kinks. I can hear air going through the fuel bowl with the hood open. So I imagine this is a good start.
I hope this is a simple repair. This truck has been so complicated. :/
 

·
Registered
Joined
·
13 Posts
Boost will be dependent on load of the engine. I can pull 8# doing 75mph @ 2200rpm empty or I can pull 26# of boost doing 75 @2200rpm towing my 5er up a hill.
 

·
Premium Member
Joined
·
7,934 Posts
Oh it's easy once you understand it and when squared away correctly, is a great truck.

No chart like that as there us a bazillion factors that effect boost.


So your doing a hutch mod and you are or are not thinking you habe injector orings still leaking?
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #16 ·
I would hope I don't have a leaking injector. Ford just replaced all 8. Ieam I had leaking injector orings for so long it contaminated the fuel tank.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #18 ·
About 6 months. Then two months ago all eight were replaced by ford in starkville ms. I changed the fuel filter right after that. And it's due for one right now anyhow. I am fixing to go pull it to see what it looks like.
 

·
Registered
Joined
·
628 Posts
Oil in your diesel isn't going to be a problem at all. It'll burn through.
 

·
Registered
Joined
·
392 Posts
Discussion Starter · #20 ·
Should I not be concerned how its either still in the fuel system or getting into the fuel system?
 
1 - 20 of 46 Posts
Top