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Full boost pressure no power

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beamer1341

Probationary Member
26
1
Mar 19, 2011
Mt. Dora, Florida
Every once in awhile while driving my car under normal load typically headed up a hill it will be more noticeable. Entering the power band and giving it 50% to WOT the turbo will spool and hold pressure but the car will not "go" (not under revving) typically the issue happens at about 2.5k-3k+ RPM. Once I realize it is doing this I usually can close the throttle and get back into it and the issue stops. Often times after this happens when I shift I can blap the throttle (like you would rev matching in a downshift) and the car will back fire a brown colored smoke. I've tried to catch this with TMO logger but it never happens when I want it to. Any help would be appreciated.

Notable Info:
1990
14b
Stock motor, exhaust
Base at 5*
Boost leak was done last weekend (after new gaskets were installed)
New Fuel Filter
FIC Clean and flow tested last month
new exh mani gaskets
Turbo outlet gasket
downpipe gaskets
only non oem parts: PR solid SMIC pipes, pacesetter mani ( flame suit is on)
MBC at 12psi
Emissions & hose delete
 
if you hadn't just done a boost leak test I would guess boost leak. whenever I have one my car going up hills exspecially bogs really bad and I have to shift early to get it to keep moving. usually it is a noticeable boost leak when that is happening though. If not that your seals in your turbo could be going out. that is a wild guess because of the black smoke. however blown pistons rings could cause black smoke but that would be a constant on going thing. you would also notice a loss of oil that way.
 
I purchased a 92 GSX hackjob here from a member looking to get away from them, it came with a blown turbo that sounded like an air raid horn and built minimal boost. Left Atlanta GA on my way back home to alabama. 20 minutes into the trip i lost pull just as you described and the car had a slight buck. Black smoke would exit the exhaust then the car would run fine for a little while. I frequently had to add oil for the remainder of the trip. 4-5 quarts total.

After it completely failing on the way home and creeping along the interstate at 20mph i got it home and checked it. Seals completely blown in the turbo and the SMIC was loaded with atleast 2-3 quarts of Oil.

Hope this story helps since you seem to be experiencing the early stages of what i experienced.
 
If the turbo gains full boost easier than usual, its more than likely a sizable leak from in between the intake manifold to intercooler(Or a bunch of small leaks) How fast does it usually take it to go full boost in RPM's?
 
Hope this story helps since you seem to be experiencing the early stages of what i experienced.

I checked my intercooler tonight, no oil found

If the turbo gains full boost easier than usual, its more than likely a sizable leak from in between the intake manifold to intercooler(Or a bunch of small leaks) How fast does it usually take it to go full boost in RPM's?

This issue has been present for a good time now, before and after fixing some boost leaks
 
I checked my intercooler tonight, no oil found



This issue has been present for a good time now, before and after fixing some boost leaks

Like Str8Tune said it could be low fuel pressure and or the fuel injectors, test the injectors with a multi-meter and make sure they read in between 2-3 ohms, if they are I'd also clean them for good measure.
 
I finally was able to catch the issue on TMO on a average drive I might pick up, at most 3 counts of knock through the whole drive. When the issue occurs I get +/- 43 counts of knock. I inspected the wires leading to the sensor, they are very brittle gonna put a new 2g KS in and see if the problem persists
 
mines a auto and is power less at all RPms except when going on full throttle.

It must be a sensor that has to do with controlling fuel doesnt it? Since the Ecu ignores the o2 sensor and fuel ratios at wot if im not mistaken. and i replaced the o2 with a different one with same results.

Any help guys?
 
well i noticed my stock fpr wasnt the oem one. I ran the denso numbers on them but i couldn't find for which car they came off.

Luckily i found a 2g oem one laying around. I swapped them out with same performance.

Any help or advice would be great.
 
OP, you cant put a 2G knock sensor on a 1G, it will not work. Along with the brittle wires on the sensor, is the black goo coming out of the sensor as well? You can get a good used 1G sensor for fairly cheap, and as long as the back of the sensor isnt leaking the jelly out of it, it should work fine.
 
Spanky, have you performed a boost leak test to confirm you have no leaks? How's the air filter looking? Do you have a logger? A logger would be most helpful in this situation cause we could see whats going on. So, basically, your car feels gutless unless you floor it, but when youre at WOT, the car feels fine?
 
I had a similar problem where I could boost and it just wouldn't go anywhere, but it only happened unless I let the car warm up for a good 10 mins before driving.

Turned out I was getting a lot of (fake) knock and it was retarding all my timing.
Might try checking the sensor, I just wen't into link and tweaked my knock settings.
 
Times like these i wish i had link...

I checked my timing and heres a pick of what i saw.
The timing mark on the crank was about 2.5 - 3 centimeters past the T mark on the timing cover.
 

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In the pic of your harmonic balancer, is that plastic shavings I see everywhere? Id check to see if the balancer is coming apart on you before tearing the entire thing apart, cause if the balancer is failing, the outer ring that the belt rides on literally can spin independantly, thus moving the timing mark on the pulley out of phase. Also, Id check the timing mark from the top, looking down, instead of the bottom looking up cause depending on what angle youre looking at the mark from, it can really fool your eyes. If you dont know when the timing belt was last replaced, itd be a good idea to do it, the balancer belt, water pump, tensioner, idler and the hydraulic tensioner while youre in there. You can get all these parts in a complete kit from several of the vendors on this site.
 
I am also having a similar problem with my stock 92 tsi 1G at WOT the turbo spools up but the car won't go ...I can let of the throttle and get back on it and it goes away until the next gear change any help would be greatly appreciated ....I have no boost leak !
 
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