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Stuttering at 2500rpm-3000rpm

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ADR2g

Probationary Member
27
0
Jul 30, 2006
n las vegas, Nevada
Alright guys, this is my first time owning a DSM. i got a 2g and im having issues with the car stuttering at around 2500rpm-3000rpm. I talked to a friend and he suggested changing the plug, wires, and coil. I did the first 2 along with an oil and oil filter change. The car runs smooth up til that specified rpm range then its starts stuttering. Another friend suggested maybe its the wastegate (stock internal), he said that normally you should be able to push the actuator arm manually and have the wastegate valve open. I tried pushing it and it takes quite a bit of strength. I'm extremely new with DSM's and also turbo's so any help or suggestions will be very appreciated.

Thanks!!

-Brand spankin newbie :confused:
 
Not yet, i just picked up the car this past friday and i haven't been able to take it to a shop because i've just been trying basic tune up items to see if it that would help. What equipment is necessary to perform such a test?
 
is there anything i can do "at home" with minimal tools on hand to check for leaks?
 
ADR2g said:
Alright guys, this is my first time owning a DSM. i got a 2g and im having issues with the car stuttering at around 2500rpm-3000rpm. I talked to a friend and he suggested changing the plug, wires, and coil. I did the first 2 along with an oil and oil filter change. The car runs smooth up til that specified rpm range then its starts stuttering. Another friend suggested maybe its the wastegate (stock internal), he said that normally you should be able to push the actuator arm manually and have the wastegate valve open. I tried pushing it and it takes quite a bit of strength. I'm extremely new with DSM's and also turbo's so any help or suggestions will be very appreciated.

Thanks!!

-Brand spankin newbie :confused:

I doubt this has anything to do with your wastegate (unless it's leaking boost), but here's what he meant:

To do the wastegate actuator (WGA) test, you first need to disconnect the WGA arm from the lever on the turbine housing. The arm sticks out the back of the gold can and runs toward the driver side. There is a small clip holding the arm on the lever. Pop it off with some pliers (careful not to damage the clip). With the arm off, you should be able to rotate the lever by hand. With the arm still on, you have to compress a big spring inside that gold can to move the arm, and it does take quite a huge amount of effort to move by hand. Inside the turbine housing, there is another arm (on the other end of the shaft that the external lever is welded to) with a big disk on it that closes off the wastegate exit (a hole inside the turbine housing that, when open, lets exhaust gasses bypass the turbine wheel, thus controlling how high your boost gets). If the wastegate can't open, you'll get uncontrolled boost and either knock like a mother (very bad for your motor) or hit fuel cut (the ECU detects when the engine is flowing what it thinks is too much air and cuts spark and fuel - that's called fuel cut).

Does it sputter above 3k or is it just a sputtering in that lower range and then it goes away at higher revs?
 
I havent gotten it above 3k ### ill switch gears just to keep the car moving. I've only driven the car from the guys house that i bought it from and just around the block.

so if i pull the actuator arm off the valve, i should be able to move the valve freely? and if i can't could that be the problem?
 
ADR2g said:
is there anything i can do "at home" with minimal tools on hand to check for leaks?

To do a boost leak test, you need to make a boost leak tester. Here is a link that describes one do-it-yourself design, but I don't like that design too much (too leak-prone). Here is another one that looks like the best design I've ever seen, but I've never tried it.

You'll also either need an air compressor or a portable air tank.

You disconnect your intake pipe from the compressor housing, and clamp the tester there (to the turbo compressor inlet). Pump it up to 20psi (make sure you set your compressor regulator to 30psi or something so you don't pump 120psi into it and blow your turbo seals). If you made the tester with the gauge on it, you can watch the pressure there. Otherwise, you need an aftermarket boost gauge to monitor how the pressure leaks down.

The idea is to be able to hold 5psi more than the boost level you're running without it leaking down quickly. If your sputtering is due to a boost leak, it's a doozy. You'll probably hear hissing somewhere when you do your first test.

Take care of all of the big ones first. Then you can tackle the smaller leaks using a spray bottle filled with super-soapy water (dish soap works fine). Spray, pressurize, look for bubbles. Check all couplers, the IC (can have corrosion holes or holes from rocks), BOV flange, TB gaskets, BISS, TB shaft seals, vaccuum lines, lower injector seals/insulators, IM/head gasket, and PCV valve.

When you get all the leaks fixed, repeat the boost leak test on a warmed-up motor. The piston rings won't seal well cold, and the boost test pressure will leak there confusing the results. Trust me, it makes a big difference in how much air leaks down during a test.

The stage 0 mods section in the tech article library describes other details of a boost leak test.

I think this should be your first test. The only hard thing to get is the air compressor if you don't have it already. The tester can be made from hardware store parts for a few bucks.
 
ADR2g said:
I havent gotten it above 3k ### ill switch gears just to keep the car moving. I've only driven the car from the guys house that i bought it from and just around the block.

so if i pull the actuator arm off the valve, i should be able to move the valve freely? and if i can't could that be the problem?

It could be a problem, but it isn't what's causing the sputtering. If the WG flapper can't open or is stuck open, you'll either overboost or underboost, but neither will cause sputtering at 2500rpm. We need to figure out the sputtering problem first, then go from there.:thumb:
 
Another couple of questions:

Do you see black smoke while it's sputtering?

Does the exhaust reek of fuel? Drive by a friend while sputtering and have him/her walk out after you pass (don't get hit by a car) and smell.

A major boost leak will result in a MAJORLY rich air-fuel mix. Super rich makes black smoke. Kinda rich doesn't make black smoke, but you'll smell it.
 
I smell exhaust fumes but its primarily because im runnin only a downpipe and no cat or exhaust, my girlfriend said she saw smoke come out the back but i dont recollect whether it was black or white.
 
kenamond said:
Another couple of questions:

Do you see black smoke while it's sputtering?

Does the exhaust reek of fuel? Drive by a friend while sputtering and have him/her walk out after you pass (don't get hit by a car) and smell.

A major boost leak will result in a MAJORLY rich air-fuel mix. Super rich makes black smoke. Kinda rich doesn't make black smoke, but you'll smell it.


ill have to have my bro help me on this one.....so just ask him if he sees smoke and if he smells gas?
 
ADR2g said:
I smell exhaust fumes but its primarily because im runnin only a downpipe and no cat or exhaust, my girlfriend said she saw smoke come out the back but i dont recollect whether it was black or white.

Do the exhaust fumes smell like gasoline?

I'd find out if it's white, blue-white, or black smoke. These different colors indicate different problems, and we need to know which it is.

Some other things to check: Pull the intake pipe off the turbo compressor when the motor is cold and reach into the turbo and check for shaft play of the compressor wheel. It should spin freely, and it should not move very much side-side, and shouldn't move in/out at all. This will give you a sense of the health of the turbo.

There are numerous other tests that can be done, but we need to find out some info first, namely, the color of the exhaust smoke and how the exhaust smells.

Plan on building a boost leak tester, as you'll want to check for boost leaks regardless of what your current problem is.

So get to work!!:thumb:
 
ADR2g said:
ill have to have my bro help me on this one.....so just ask him if he sees smoke and if he smells gas?

Yes...and what color the smoke is. Burning oil is almost white with a slight blue tint. Burning coolant is white. Rich-as-shit is black. So the color is very helpful.
 
Ok will do, i will keep you guys posted on the color.

ill go check the shaft play right now.
 
ok i checked the turbine, it spins freely with lil or no shaft play at all...but i did notice that there was oil within the intake....is that a big problem?
 
ADR2g said:
ok i checked the turbine, it spins freely with lil or no shaft play at all...but i did notice that there was oil within the intake....is that a big problem?

Maybe. Maybe not. The VC breather hose (goes from the passenger side of the valve cover to the intake pipe) will blow oil vapor into your intake, and that's normal. So this oil collects all through your intake system. What you can do is clean out the oil that's in the compressor outlet (not the inlet where you checked for shaft play), disconnect the VC breather from the intake pipe, let the tube hang, and cap the nipple on the intake pipe. This removes the oil source and also keeps unmetered air from getting sucked in through the open nipple. Then drive around such that you get full oil pressure. Afterward, check for new oil in the compressor outlet. If you see fresh oil in there, the turbo is leaking oil. If this is happening, you're probably going to see blue-white smoke under boost, and your turbo needs replaced or rebuilt (UPGRADE!!!). Since you can't hit full boost (4k rpm), the turbo won't have enough oomph to push the oil into the cylinders, so you may not see smoke from this...yet.

When you're done, put the VC breather hose back on so you don't forget, but you should definitely consider doing a few other things in this regard (don't need to yet, but after you've fixed the sputtering problem). First, you can put a fuel filter in that VC breather line to keep oil out of your intake tract. Why? Because the oil layer degrades the performance of your intercooler and gums up the throttle body and cylinders. Second, you can disassemble your intake tract (lower IC pipe, IC, upper IC pipe, S-hose - everything from the turbo to the throttle body elbow) and clean it all out. You can also inspect for wear, corrosion of the IC, etc. The biggest help is to clean your IC out with gas.

If you do this test and don't see new oil, it looks like your turbo is in good shape.
 
Not trying to hijack this thread but i am having a similar problem. My car sputters and jumps real bad at those rpm levels. i am completeing stock except for bov. And when my car sputters it puts out black smoke. And i can't get it to go above 60 miles per hour. could this be a cloged cat or is it most likly bost leak?
 
Whats the sputtering like? Like misfiring with a back fire? or just like its running on 3 cyl? cause it could mean different things. Check the pulgs and plug wires I had a bad plug wire and it would arch inside of the plug well and not fire the plug.
 
the bov is not recurculated. i didn't do this it came like this. I did a boost leak test and it was my throttle boddie leaking. i just put another one on and now my car is running worse than ever. it sputters real bad and won't go over 2 grand. what could be going wrong
 
Pull your timing cover and check your timing marks. Sounds like it jumped a tooth. If so, change the entire belt, don't just reset it.
How many miles does it have?

Latr, Duane
 
CHECK FOR BOOST LEAKS. That's what it sounds like to me, it's cheap and easy and you're going to have to do it at some point anyway. My lower intercooler pipe popped off one time and I couldn't get about 3K and pouring out black smoke, put it back on and she was back to her old self. It's worth a shot at least.
 
ok, im plannin on doing a boost leak test soon, but i want to tighten down the couplers first to see if that helps. now, if i remove the couplers do i have to worry about anything spilling out (oil, coolant, etc.) im really new to the turbo scene so i dont know exactly what happens when you take the assembly apart.....and damm those couplers are expensive!!
 
PSI NRG said:
Whats the sputtering like? Like misfiring with a back fire? or just like its running on 3 cyl? cause it could mean different things. Check the pulgs and plug wires I had a bad plug wire and it would arch inside of the plug well and not fire the plug.


when i accidentally switched the plug wires on my honda it was causing misfires that resembled wuts happenin to my 2g now, but i know for a fact that my wires arent crossed cause it idles and runs fine up til 2500, they are also new plugs and wires.
 
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