not reaching full boost until 6000 rpms in first gear and it smokes

[bmwracing_6]

i am new to dsm's and everything. i just bought a 92 GSX with 177,xxx milesand it runs really good. but there are a few problems with it. first it smokes some times just a little and sometimes a lot do i need to replace the piston rings to fix this. i have heard that alot of the 4g63's smoke at old age. also i think the turbo is bad on it cause i am not reaching full boost until 6000 rpms in first gear. my future plans are to get a hoset turbo with a dsmlink and 3in exhaust with a front mount intercooler this summer but for now it is parked until i get the money to even put insurance on it.

 

[drivemusicnow]

i am new to dsm's and everything. i just bought a 92 GSX with 177,xxx milesand it runs really good. but there are a few problems with it. first it smokes some times just a little and sometimes a lot do i need to replace the piston rings to fix this. i have heard that alot of the 4g63's smoke at old age. also i think the turbo is bad on it cause i am not reaching full boost until 6000 rpms in first gear. my future plans are to get a hoset turbo with a dsmlink and 3in exhaust with a front mount intercooler this summer but for now it is parked until i get the money to even put insurance on it.

Settle down there.

First thigns first, Smoke out of the exhaust can be caused by a couple different things. ONe of them could be the turbo seals being old/worn. this leaks oil into the exhaust and then burns creating smoke. Another is a blown headgasket leaking coolant into the cylinders. Worn rings can let oil into the combustion chamber to burn as well.

There is a problem if you're not reaching full boost until 6k rpms, however test in second or third gear.

Now, has anything aftermarket been done to the car? have you done compression and leak down tests? Have you check spark plug gap/ wires?

Basic maintenence on these cars MUST be done before you throw go-fast parts onto it. Your first purchases should be replacing worn parts, and logging tools and gauges.

 

[JDNSBR]

Agreed. Simple maintenance first before going crazy. Greg is correct in telling you to check compression and having you check your plugs as well. Also, boost leak test. Being new to thse cars you will learn fast enough that any small boost / vaccum leak can cause one hell of a headache.

A couple other things to check if you get good results with the compression and boost leak test is to take off your lower intercooler pipe and intercooler. If your seals are shot in your turbo you better believe it will be going thru your entire intercooling system. If you get oil in your pipes and intercooler it is putting even more stress on an already hurt turbo as it will decrease the airflow. Let us know what you find. Good luck!

 

[DSM_NOOBIE]

Another issue could be that the Valve stem seals are old, allowing oil to seep through the guides and burning up causing smoke. Also you could be running rich.

Blueish black smoke= burning oil
white smoke on warm to hot days= coolant burning or running in lean conditions this one is a bit tricky
black smell of fuel from tailpipe= runing rich
check coolant bottle for milky color=blown headgasket
check the turbo outlet piping for oil= blown turbo seals

all else fails u might need to look internally and do a rebuild

 

[spyderturbo007]

First thing I would do is check the turbo for shaft play. Just yank off the intake and check for both axial and radial play.

 

[MrBoxx]

Everyone pretty much summed it up.

I'll add a few things: On most cars, it's difficult to achieve full boost in first gear due to the lack of load on the engine. As Greg said, check what rpm you reach full boost at in second and third gear. If it's the same, check for boost leaks, turbo damage, and exhaust leaks.

Also, at 177k miles, there are likely several parts that are "tired" and could probably use a replacement. These include the valve stem seals/guides, the turbo (likely, especially if it's the original turbo) and possibly the pistons and rings. A compression/leakdown test should be in order to tell if anything is possibly wrong with these components.

my future plans are to get a holset turbo with a dsmlink and 3in exhaust with a front mount intercooler

There are a few things you should probably get in the manner of supporting modifications before you jump up to those parts, i.e. fuel pump, injectors, intake, etc. I'm sure you have those in mind, though.

 

[95talon_in_ma]

What guage are you using to measure your boost? If it's the stock one, it's very inaccurate. If it's an aftermarket, make sure it's hooked up right.
I have a stock T25. It reaches full boost by 2500 rpms. If you just got this car, firsth thing you should do is a complete tune up. Replace all of your vacuum lines etc. Do a boost leak. And then do a compression test.
Once you know the exact state of your motor, you can upgrade as necessary. At 177K, I'd be doing a rebuild first and foremost.
Good luck!

 

[want_a_gsx]

yeah i noticed the same problem after a while. everyone was hitting full boost way before 4k, i always got it close to 5k rpm.

checked compression and sure thing, motor is shot. you might want to do a compression check. you can buy the parts an at auto parts store for around $20ish and do a compression test following the instruction in vfaq.com.

good luck