HELP!? Can't make more than 15 psi

brandonb

brandonb

When in doubt GAS IT!!
OK, I am at the end of my rope here. The truck pulls well up to about 15 psi before it starts to break up and shudder and won't make any more boost. It just kind of stops there. I can hear a flutter in the turbo as it is doing it as well. I have checked everything I can think of and I have seached everything I can find on here as well. The datamaster logs show nothing out of the ordinary which is leading me to believe it may be something mechanical.

Here are the things that I have done and checked:
no exhaust leaks
new 3 bar map
new wastegate
IC has no leaks
all new vacuum hoses
new boost control solenoid
no cat
tried different chips (standalone and wideband piggybacked, code 59)
have tried stock o2 sensor and plx
no shaft play or wheel damage in turbo
no intake leaks
new plugs (ngk ur5)
new wires
new cap and rotor
walboro 255 fuel pump seems to be fine (fuel pressure is 40psi at idle but 60psi at 15 puonds of boost?????)
coolant temps sensors are new
knock sensor has NOT been replaced
turbo is detriot turbo tdo4e 57 trim
new ecm
160 degree thermostat
50lbs. injectors
And the list goes on...

I get knock retard readings from datamaster that seem to be false because there is definitely no audible knock happening. It happens whether it is set a 0 degrees or 7 degrees advanced so I think it is a false reading, it sometimes starts to pull timing at 7-8 psi of boost because of this reading. Could this be a bad knock sensor? Maybe a bad coil? Those are pretty much the only 2 things I can think of that have not been replaced.

Thanks in advance.

Brandon
 
nello

nello

Active member
Re: HELP!? Can't make more than 15 psi

Don't know what kind of wastegate ya have but on my external wg with the actuator rod, it was WAY off. I only was getting 5psi until it was adjusted correctly. Before that boost was just leaking out. Because you said it's new i'd defintilely take one more look.
 
brandonb

brandonb

When in doubt GAS IT!!
Re: HELP!? Can't make more than 15 psi

I do have an external wg, I have adjusted that nothing, i've even wired it shut and the same results.:(
 
bezerk

bezerk

New member
Re: HELP!? Can't make more than 15 psi

i would look a bit deeper in the knock issue instead of pushing it in boost. you are asking for an engine rebuild
 
Luke

Luke

Fish sticks SUCK !!!
Re: HELP!? Can't make more than 15 psi

datamaster knock does not = audible knock, if you can hear knock it might as well be too late. I would keep the boost at stock and lose the knock before going any higher
 
berzerker

berzerker

wookie
Re: HELP!? Can't make more than 15 psi

brandon what are your spark plugs gapped at ? try .025 gap , also do you still have the flowmaster muffler on the truck ? if so toss it and get an round straight thru design like magnaflow . call me if want so help.
 
TYTILIDIE

TYTILIDIE

METH HEAD
Re: HELP!? Can't make more than 15 psi

berzerker said:
brandon what are your spark plugs gapped at ? try .025 gap , also do you still have the flowmaster muffler on the truck ? if so toss it and get an round straight thru design like magnaflow . call me if want so help.
Click to expand...

Had this problem myself when I upgraded turbos a few years back. At the very least check them out to make sure they look decent.
 
brandonb

brandonb

When in doubt GAS IT!!
Re: HELP!? Can't make more than 15 psi

Thanks guy's for your help. I will try them at .25 instead of the.30 I'm at now. I'm also going to add a new coil to that list as well. Mine is still the stock one from the factory..
 
brandonb

brandonb

When in doubt GAS IT!!
Re: HELP!? Can't make more than 15 psi

Thanks for the help Jeff and the rest that replied. Put Jeff's new coil on, new plugs gapped at .026 and its starting to come alive again. Now on for some tunning:D
 
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