Turbo boosting 2psi only, stumped.
#1
Turbo boosting 2psi only, stumped.
I feel I can get better/faster information here than on m.net.
Little backstory. Car is a '92 Black and Tan. Has a Greddy kit on it.
I bought the car about 2 months ago, it had been hit by a deer and when I went to check it out it did not start. I looked it over and found a blown main fuse. Talked him down a bit, came back, replaced the fuse and the car started right up, with some blue smoke of course.
I get the car home, find out there are a lot of things wrong/jerry rigged/lazily done.
-Sebring Timing Box crimped into the CAS wires
-Vortech FMU
-Heater hose used for oil drain.
-A/C lines cut
-Heater core brass lines cut
-CLT wiring fucked
-Massive exhaust leak
-Nasty bad old gas
-Mold inside car
-Top torn
Plus a lot of other little things.
I basically tore the car down, check keyway, timing, wp, etc etc. Pulled exhaust manifold, turbo, downpipe off the car. I did not get the surfaces milled flat. I did take an emery cloth and worked on each surface. Then I installed brand new hardware, new gaskets, and torqued them down till I couldn't anymore. Go ahead and flame me on that one, I don't care. This car will not see more than 5-6psi. I am not building this car, I am simply trying to get it running right.
I have fixed everything. The only thing that eludes me now, is the turbo is not boosting past 1-2psi.
-I have checked wastegate operation. It starts moving around 5psi and is fully extended around 12psi.
-I have eliminated my intercooler as to remove possible leaks.
-I have installed a WBo2 that is now working correctly.
-The FMU is doing it's job, at the 2psi I am seeing it is running 10.5-11.5 afr (not the greatest, but not dangerous)
-I have no exhaust leaks
-I cut reliefs in the exhaust manifold between 1-2 and 3-4.
-I have adjusted the preload on the actuator both ways with no change
-I have unhooked the vacuum going from the compressor outlet to the wastegate actuator and wired the wastegate closed, no change.
-I have removed my BOV to eliminate possible leaks, no change.
-The turbo itself has little side to side play and no in/out play
The only thing I have not done is pressure test my charge pipes. With that I have a question though. If I have my boost gauge spliced into the vacuum line coming from the compressor outlet to the wastegate, if I had a leak in my charge piping, would the pressure I see at the boost gauge reflect that? Basically I'm asking, going with the flow of air, if I had a boost leak, would the pressure be the same in the entire routing of the charge piping, or would the pressure be higher the closer you got to the compressor outlet?
Thanks for any help guys.
Little backstory. Car is a '92 Black and Tan. Has a Greddy kit on it.
I bought the car about 2 months ago, it had been hit by a deer and when I went to check it out it did not start. I looked it over and found a blown main fuse. Talked him down a bit, came back, replaced the fuse and the car started right up, with some blue smoke of course.
I get the car home, find out there are a lot of things wrong/jerry rigged/lazily done.
-Sebring Timing Box crimped into the CAS wires
-Vortech FMU
-Heater hose used for oil drain.
-A/C lines cut
-Heater core brass lines cut
-CLT wiring fucked
-Massive exhaust leak
-Nasty bad old gas
-Mold inside car
-Top torn
Plus a lot of other little things.
I basically tore the car down, check keyway, timing, wp, etc etc. Pulled exhaust manifold, turbo, downpipe off the car. I did not get the surfaces milled flat. I did take an emery cloth and worked on each surface. Then I installed brand new hardware, new gaskets, and torqued them down till I couldn't anymore. Go ahead and flame me on that one, I don't care. This car will not see more than 5-6psi. I am not building this car, I am simply trying to get it running right.
I have fixed everything. The only thing that eludes me now, is the turbo is not boosting past 1-2psi.
-I have checked wastegate operation. It starts moving around 5psi and is fully extended around 12psi.
-I have eliminated my intercooler as to remove possible leaks.
-I have installed a WBo2 that is now working correctly.
-The FMU is doing it's job, at the 2psi I am seeing it is running 10.5-11.5 afr (not the greatest, but not dangerous)
-I have no exhaust leaks
-I cut reliefs in the exhaust manifold between 1-2 and 3-4.
-I have adjusted the preload on the actuator both ways with no change
-I have unhooked the vacuum going from the compressor outlet to the wastegate actuator and wired the wastegate closed, no change.
-I have removed my BOV to eliminate possible leaks, no change.
-The turbo itself has little side to side play and no in/out play
The only thing I have not done is pressure test my charge pipes. With that I have a question though. If I have my boost gauge spliced into the vacuum line coming from the compressor outlet to the wastegate, if I had a leak in my charge piping, would the pressure I see at the boost gauge reflect that? Basically I'm asking, going with the flow of air, if I had a boost leak, would the pressure be the same in the entire routing of the charge piping, or would the pressure be higher the closer you got to the compressor outlet?
Thanks for any help guys.
#2
Former Vendor
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Pressure is the same in all of the charge piping, basically. The difference will not be large enough for you to accurately measure with a standard boost gauge. 2psi is either a wastegate flapper that isn't closed or a big boost leak.
#3
I'm a terrible person
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Join Date: Apr 2009
Location: Arizona
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I read 10% of what you wrote, mainly your checklist, didn't see what are you using to check boost pressure? Is the gauge accurate? Is the line connected and not crimped somewhere? If the dude hit a dear maybe the impact pushed something against the vac line. To only make 2psi you have to have a pretty big leak if it isn't the gauge...
#6
Cpt. Slow
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Posts: 14,179
Total Cats: 1,129
I would blame your turbo. If youvd simplified your charge pipes to only a few couplers to run without an inter cooler, I'm guessing you would have found a leak big enough to only create 2psi. Does the turbo spin freely by hand? Does it spin for a minute after shutting down the engine from an idle?
#8
I still have about 5 couplers. I'm pretty sure listening to this
and then my car (try to ignore the intake induction sound, I have the hood off)
Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting
It has to be a boost leak.
and then my car (try to ignore the intake induction sound, I have the hood off)
Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting
It has to be a boost leak.
#16
Only bandaid I have hooked up right now is the FMU. I took the Sebring box out completely. Everything was split off of one vacuum port, so I spread them out. No more than two things per port now.
Will a clogged cat cause the car not to boost? I have not checked the exhaust yet.
The pinging sounds were my shift **** rattling around.
I didn't actually have the turbo apart. The only thing I did was take the vband off and tried to separate the exhaust side. When I found out it had large c clips I stopped and put it back on. I had to look up what chra meant :(
Will a clogged cat cause the car not to boost? I have not checked the exhaust yet.
The pinging sounds were my shift **** rattling around.
I didn't actually have the turbo apart. The only thing I did was take the vband off and tried to separate the exhaust side. When I found out it had large c clips I stopped and put it back on. I had to look up what chra meant :(