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low boost

4K views 30 replies 7 participants last post by  sgleshot 
#1 ·
ok, now that I have the ts 6 position chip in my rig, should it build more boost? on the highest setting at WOT the gauge says I'm only getting about 14lbs. This is an early 99 7.3 if it makes any difference, it doesnt look or sound like I have any exhaust leaks, everything runs smooth. I just dont think I'm gettin the boost I should. Any Input?
 
#2 ·
oh, the rig is straight piped with diy afe intake. Other than those two and the ts chip there are no other mods. and its a standard.
 
#3 ·
So, You've got it straight piped, TS 6pos chip, and a afe intake, and About 14lbs boost... I guess that sounds about right if your brake torquing it... I don't think that should be at WOT going down the road. IDK, my truck when I bought it had a 6.0 Swap... Althought its a 2001...
 
#5 ·
you should be seeing around 22-25psi with a chip. Does it boost like crazy and hit 22-24psi and then back down to 14psi? OR does it never make it? If it naver makes it check all of your clamps on your intercooler boots.
 
#6 ·
yeah, it never makes it there, that 14lbs is WFO all the way, killin bugs as I go and stoppin traffic. I also noticed that I more of less dont have a whole lot of boost around 1500rpm, thats about where the needle starts to move, most movement occurs after 2k.
 
#7 ·
Wow, I think their might be some damage to your Compresser wheel. The bearings in the wheel may have something wrong with it.. Take the Housing off and get into the internals check her out. It also might be something with your gauge, but if she's not whining like it did stock or not at all.. This may be it.. How many miles are on it?
 
#8 ·
its got 110k on the ticker, I can hear the turbo spoolin nicely, everything sounds like it is running nice.
 
#9 ·
Make sure you don't have any kinks in the boost line to the gauge. Is it a T off the map line? Also make sure all your clamps to your intercooler tubes are tight you might have a leak.
 
#10 ·
ya its the t style, I'll check the intercooler hoses tonight, if that line is kinked, can I use copper tube like for an oil pressure sending unit on it?
 
#11 ·
My early 99 will hit 25lbs in no time at WOT it boost righ up there very easily and will stay there if I keep the pedal floored, but I usually dont because of fear of blowing my turbo.
 
#12 ·
Honestly I haven't heard of anyone using copper tubing:dunno: I guess I would worry about getting the copper to seal around the ends.
 
#13 ·
I use it for lines to oil pressure gauges on my race trucks, I just didnt see why it wouldnt work, and its more rugged than the plastic garbage.
 
#14 ·
Yeah I can see it working on the back of the gauge with a compression fitting, but probobly would leak on the T. If you used a compression fitting on the other end then I don't see why it wouldn't work.
 
#15 ·
yeah the motor end came with a plastic t and then brass compression fitting that bolts onto it. would it be more accurate to put it somewhere else?
 
#16 ·
Oh okay so there is a compression fitting on the T? I always thought it was just a slip on with a hose clamp for the T. I used a air intake heater plug with boost fitting. You remove the aih and plug the hole with the fitting on the Y-pipe. Do you have an early 99? If you do then you don't have the aih. The T is fine or you could drill and tap the Y-pipe.
 
#18 ·
now in neutral should this be able to build boost or does it need to be under load?
 
#19 ·
Yeah you need to be under load. I remember the first time I installed mine and was mashing the pedal and there was no boost! I figured I did somthing wrong:lol:
 
#20 ·
Also pull the red hose off the turbo wastegate. You could have a wore out wastegate, I had one. It would not hold 12psi. I replaced it and I went to a max of 32psi. Then I had to tune it down to 28psi.

While you are checking the hoses tonight, grab a flash lite and look between the engine and the fire wall. Look for black soot on the fire wall and at the connections between the up pipes and the headers and the bay butt. You could also have an exhaust leak letting the back pressure out before it can spool the turbo.
 
#21 ·
I know I dont have any leaks in the up pipes, or the exhaust manifolds, now let me get this straight, if the waste gate is wore out it wont build boost? now if I disconnect the red hose going to it and then it builds pressure that would mean the wastegate is junk?
 
#22 ·
Its possible the spring in the actuator could be bad. The spring holds it shut the red line applies air pressure to start to open the wastegate at around 5 psi to bleed boost. If you remove the red line it will hold the wastegate shut longer as long as your spring isnt shot.
 
#24 ·
ok, so I unplugged the red line going to my wastegate, and I also wired the arm on it so that it couldnt open to see if that made any change. it didnt. Next I unhooked the hose going to the map sensor, connected an air hose, then plugged the intake, I couldnt hear any air leaking out, then I found a small kink up by the gauge, fixed that, and after all that it still shows only around 10 to 12 pounds of boost. I then thought it could be the gauge, so I hooked up an oil pressure gauge, figured it was the same concept. and that gauge read the same. Then I took off all the blue connectors for the intercooler and checked them to see if there were any holes, there wasnt. I'm lost.
 
#26 ·
Hmm did you block the black rubber boot on the red line so no air could escape? What you should do is block the intake off again and if you can dial up the pressure from your tank to say 15 psi and leave it for 15 minutes or so and see if it leaks down. In other words pump your tank up to ony 15 psi and see if the tank leaks down. Did I make any sense?
 
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