find boost leak

IdahoRob

IdahoRob

New member
Jun 5, 2007
1,151
0
0
05lly2500hd said:
I can hear it, SOUNDS like it's on the lower driver's side, but it's VERY VERY VERY hard to hear. I've give the compressor a shot. So say pull CAC off stocker and put compressed air into CAC driver's side pipe and just listen for a leak? How do I regulate, control how much psi is put into system? Do I need to use a gauge? or would me autometer work??

It just ticks me off, I should be running alot quicker, tonight I could only muster a 13.55@98mph.

Could a MAF or EGR cause this symptom? What about head gaskets with no other symptoms?
Click to expand...


I build the tunes so if you can't run good rail pressure, it'll pull fueling until it can maintain decent rail pressure.

Your logs show that your truck can't even hold 2500us when an avereage LLY single cp3 truck will hold 3100+. This is one of your big problems. Fix the fuel supply issue. Also one of the reasons your truck is running cool egt and little smoke, it's not fueling hard.

Fix the boost issue. When the proper fueling is reached, you will see more egt's and smoke with a boost leak.

These two problems need to be fixed before you will go fast.
 
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
My truck won't hold 2500us. Where do I begin to look?

on edit: oops, I was on my blackberry, didn't see rob's post.
 
Last edited:
TrentNell

TrentNell

Finally underway !!!!!
Jul 7, 2008
7,543
0
0
44
slc tuah
05lly2500hd said:
My truck won't hold 2500us. Where do I begin to look?
Click to expand...

2 things first , make shure the rail pop off isnt popping, it will require you to do a bottle test to check it , secound thing is the CP3 could be getting weak !

Edit: i would verify what lift pump pressure is also .
 
Last edited:
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
TrentNell said:
2 things first , make shure the rail pop off isnt popping, it will require you to do a bottle test to check it , secound thing is the CP3 could be getting weak !

Edit: i would verify what lift pump pressure is also .
Click to expand...
yea I'm trying to find an adapter 1/8 NPT female to M10-1.5? and use my boost gauge temporarily to check fuel pressure from lift pumps. They do have power and I can hear them running, just need to see how much psi they are putting off.
I did a bottle test a while back and it popped but that was before shimming it. I know last night it did set a 1093. Maybe I need to add another shim...maybe my cp3 is bad! damnit.
can anyone point me in the direction of the bottle test thread?
 
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
also, don't know if this is relevant or not, but it's been a hard crank for some time. Turns over a bit before cranking. Can't remember what I did, but somehow with efi i made it a lil better, i believe i added cranking inj. qty. maybe?
 
IdahoRob

IdahoRob

New member
Jun 5, 2007
1,151
0
0
Even with a race valve the rail can be leaking. Do a bottle test as Trent stated.

You'll need to see fuel pressure while at WOT, so I don't think a boost gauge is a good idea Jeremy, at least not in the cab. With all the mods you have, you'll like having a real fuel pressure gauge.

Look into bottle test, faulty lift pumps, faulty fuel pickup in the tank, bad fuel filter, air leak around filter or WIF sensor, and lastly weak cp3.
 
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
IdahoRob said:
Even with a race valve the rail can be leaking. Do a bottle test as Trent stated.

You'll need to see fuel pressure while at WOT, so I don't think a boost gauge is a good idea Jeremy, at least not in the cab. With all the mods you have, you'll like having a real fuel pressure gauge.

Look into bottle test, faulty lift pumps, faulty fuel pickup in the tank, bad fuel filter, air leak around filter or WIF sensor, and lastly weak cp3.
Click to expand...
Well the guage is electric I just didn't know if the sensor would read accurately.
I just wanna try and spend the least at least until i figure it out, don't wanna spend a grand on a guage and pumps to find out the cp3 needs replaced, lol its my luck though.
I will work on this.
Rob, thanks a ton for the help, I know i've bugged the hell out of you through email and phone. I appreciate it.:beer

I'm gonna go ahead and replace filter and WIF sensor and do the bottle test...hopefully tonight.Then go from there....Well I got a filter to swap, they wanted $89 for WIF sensor, I'll just get one from Eric.
 
Last edited:
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
well no fuel in the bottle! haven't been able to change filter yet, two young boys, one almost 3 and the other almost 2 take up lots of time and energy, lol. I've got a feeling it's the cp3. The lift pumps are fairly new and not only having it crank over a bit before starting, etc.
One of my employees has an air compressor and is gonna help me do the pressure test, just have to find a cap or something to plug off the tract, something like 5" ID. Got a soapy water bottle ready too.

I have a question though.............may be stupid but I'll give it a shot....
Would I be able to tell if my cp3 is bad, by running a stock tune with lift pumps off and logging it? Being that the tune isn't asking for much fuel it should be able to sustain the commanded pressure, if it doesn't...then what else could it be besides the cp3? Of course after changing filter and doing the bottle test.
 
Last edited:
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
I guess it wouldn't neccesarily work because if the cp3 is weak it may not show it until it is really pushed, say asking XXXXus on a stock tune is one thing, asking more XXXXus on a big tune is gonna really show it's weakness.............right?
Just trying to understand.
 
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
JoshH

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,765
834
113
Texas!!!
Ya, they must have stopped carrying that fitting. I haven't looked at the link for a while, but it used to be 1.5 pitch. It still says it in my bookmark folder. I guess I'll have to delete it and stop posting it. It redirects to the 1.0 pitch fitting from the 1.5 link.
 
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
JoshH said:
Ya, they must have stopped carrying that fitting. I haven't looked at the link for a while, but it used to be 1.5 pitch. It still says it in my bookmark folder. I guess I'll have to delete it and stop posting it. It redirects to the 1.0 pitch fitting from the 1.5 link.
Click to expand...
ok gotcha!
 
05lly2500hd

05lly2500hd

(903)293-6026
Feb 16, 2008
473
0
0
45
Texarkana, TX
JoshH said:
This is what I bought for my truck before I found what I tried to direct you to (which did used to be the correct fitting). I'm gonna put a T in between the adapter and the needle valve.

http://lubricationspecialist.com/front/shop.aspx?catid=10&parentid=0&productid=42
Click to expand...
LOL, I was gonna order from him but decided to find your thread about the above you posted, because I knew it was cheaper, ROFLMAO. Hell of a coincidence huh? I think I"m gonna order from here(lube special)
 
IdahoRob

IdahoRob

New member
Jun 5, 2007
1,151
0
0
You can also get a perma-cool filter head and filter from Jegs or Summit for around 35.00. Then just use standard npt fittings and hook up your pressure sensor. I use CAT filters for replacement filter and save that expensive stock filter for longer.

This is what is on my daily driver as well as the race truck.
 
You must log in or register to reply here.
Top Bottom