car is lagging around 3000 rpm help!

[twitchferd420]

i got a 98 gsx..just got the car 6 months back and everything is stock except the greddy blow-off. when i get on it it starts to lag arounnd 3000 rpm but once i pass it all seems to be well...i was told maybe a misfire? but im not getting a CEL...any suggestions...? i checked the spark plugs...they seem to be fine,probs gunna get new ones any way just to be on the safe side...please help!!

 

[turbodude]

Are you sure it's not just standard turbo lag? has it always done this since you got it or is it a recent occurrence?

 

[twitchferd420]

it just started the day i put the BOV on....maybe i just never noticed it until the BOV was put on

 

[stefanOst]

Have you done a boost leak test, particularly since you installed the new BOV?

 

[twitchferd420]

i have not done that yet...how can i go about that...this is all new to me..ivew never owned a car with a turbo

 

[turbodude]

Well, if this started to happen after installing the BOV i can pretty much assure you that's the problem. Either A: a boost leak perhaps around the seal of the BOV and I/C pipe itself or B: If it is a defective or knock off greddy BOV it could have a flimsy or torn diaphragm allowing boost to fluctuate and perhaps leak.

Also, make sure you installed your bov properly and tapped in to the correct lines. there are threads on this forum for proper install of a greddy bov.

 

[twitchferd420]

i know its not a knock off and it was used for a evo8 but it was flanged for my dsm...also i had a buddy of mine give me a hand putting it on and the only thing is its a BOV and deverter but i have not hooked up the deverter part yet since i would need to split one of the lines and i dont have the little plastic T looking thing

 

[turbodude]

Few questions...

1)Is it a Greddy type-s? typically are purple in color. With one larger nipple on top and a smaller one on the bottom?

2)Also, are you running the new BOV recirculated or vented?

3)And was your car running recirc or VTA prior to installing the new greddy bov?

 

[twitchferd420]

im running the BOV recirc and it was running that that befor i did it and yes i belive its the type s

 

[turbodude]

Okay, gottcha... So if you are sure that the seal is solid between the bov and i/c pipe then that's not the issue. You have the recirc tube connected as it was previously so that's not the problem.

The only thing i am unclear about is you said you need the little plastic t-fitting to connect the diverter? how do you currently have the vacuum lines connected to the bov? you only need the upper (larger) nipple connected, which it should be right now in your set-up.... The bottom one does not need to be hooked up, so why do you need the t-fitting? Or are you telling me that currently you just have the bov connected to the i/c pipe being recirc'd with no vacuum lines connected to the back? if so, there's your problem right there.

I don't mean to insult you by asking simple questions like this, but sometimes the simple things are what get ya,

 

[twitchferd420]

haha i got you its not insaulting...and i the T fitting well after what u said isa yea i ment the t fitting to go to the other one that you said doesnt need to be hooked up so thats not the issue..so im pretty sure there is no problem with the BOV...what eles could i look at?

 

[turbodude]

I would still do a BLT (boost leak test) for piece of mind. to find out how, just do a search on here. You can check out youtube as well, plenty of instructional videos on how to build your own boost leak tester and how to do the procedure. Real simple, as I made a solid one completely with parts from home depot. Here's one example of a video on youtube on how to do a BLT with a DIY approach:

Boost Leak Tester DIY - YouTube

Also, Have you checked your timing at all? perhaps it may have jumped a tooth and is a little off. Wouldn't hurt to check it anyway, and inspect your timing belt while your at it. That way you know it's good to go because the last thing you want it a timing belt misfortune. here's a thread of how to easily check if your timing is on point:

http://www.dsmtuners.com/forums/art...-1g-2g-quick-timing-belt-alignment-check.html

Good luck man

 

[twitchferd420]

thanks man i really appreciate the help and also i just had the timing done about 4 or 5000 miles ago due to someone ####ing up the timing befor i bought the car all my exhaust valves were bent...ha that was a pretty penny!! but i dont think its the timing

 

[turbodude]

No problem, maybe someone else will chime in as i am sure it could possibly be a variety of other things, but if the BLT doesn't solve your problem then i'm outta ideas. laters

 

[twitchferd420]

well i found that my piping from my intercooler to the turbo was loose a lil bit...i was poking around at it when i found it...im at work so i will see if the problem is gone...and if it is then a BLT would have found it...thanks man...hopefully its solved

 

[turbodude]

Yeah, no problem. A BLT would have definitely found it if you didn't find it yourself. Let us know if it's all fixed now, as i am now pretty confident that was your problem. Later

 

[twitchferd420]

It wasn't the problem

 

[97ebaygst]

can you explain the problem in more detail? is it stumbling, is it low boost, etc? it will help determine the problem easier.

 

[twitchferd420]

it boost..but once it gets to its max it kinda drops a little bit then back up and the car actually lags like it bumps as i am still giving it gas....i still need to do a BLT i just havnt had the time to run to home depot the buy what i need to do it

 

[twitchferd420]

well i found out where the problem is...its at the turbo but on the exhaust side...i think its coming from by the O2 senser housing....any suggestions on that...i will be taking the manifold off with the turbo and doing a visual inspection...im also going to get new gaskets and what ever eles is needed....anything eles i should look at or do since i got the turbo and manifold off?

 

[CrawlinZX14]

ummm if its a boost leak like you described there, then its not in your exhaust. Chances are your BOV is opening slightly and allowing air to bypass. If you didnt have it recirc im sure you would hear it better. Is this at only cruising speeds or WOT? My stock BOV does this to me all the time cruising but as soon as I go WOT it will close off and boost hard. But easing into it it stumbles. Im replacing my BOV with a SSQ I picked up, but im willing to bet its in your BOV. the valve is likely opening slightly. Take the recirc off and take a cruise around the block. If you hear a rush of air as the problem persists, then its your BOV opening. Chances are with it not recirculating it will make the car run like crap until you let off enough to get out of boost, or you go into more boost. Mine does it from about 4psi to about 8psi at highway speeds. Try adding a little tension to the spring in the BOV making it harder to open. that may help.

It could also be your wastegate opening causing a lag too. You may want to check you actuator if you have an internal wastegate.

 

[twitchferd420]

well no after driving i open the hood then turn my car off and i see smoke coming from the exhaust side of the turbo and when you rev it and put you hand near where the smoke was coming from and sure enough there was air coming from there...i had a guy look at ut and he said thats def the problem because the turbo is spooling and building presser but then it never goes back into the motor

 

[CrawlinZX14]

I think Im a little confused then. You said it was on the hot side at your O2 housing this leak is coming from. Meaning after the turbo. The cold side is the silverish colored side and that is the side that will return to the engine. Meaning that is a boost leak and a BLT would have told you that was the issue. If its on the exhaust side after the turbo, it will have little to no effect on your boost levels. Unless you have an external waste gate and your venting exhaust away from the turbine. And that is between the head and the turbo ONLY. The smoke coming off the mani is likely from you putting your hands on the mani. Your greasy and oily finger prints will make smoke roll off it right after you mess with it. Hell when I did my mani gasket I used rubber gloves and it still smoked after the test drive.

So again, if your boost level is fluctuating you have a boost leak or a faulty waste gate. There is nothing else that would cause boost pressures to fluctuate like that. Now a boost leak can be a loose connection, a vac line not being connected correctly, a faulty BOV leaking pressure either to atmosphere or into the intake pipe, a bad gasket in the J pipe, TB or even a leak in your system like the intercooler or in a hose.

The wastegate would be another place because it allows exhaust gases to simply bypass the turbine and thus lowers your boost pressures. Either way, that is the only way an exhaust leak would effect your boosting like that. Many turbo people just dump their exhaust out the side or under their cars. A turbo car is not a small block needing to scavenge air out of the exhaust as there is little to NO overlap in the cam duration.

I would question your friend that told you an exhaust leak was the cause of a boost issue, especially if it was in the O2 sensor area. thats also called a turbo elbow or down pipe. Either way, it does not recirculate into the engine ever at that point.

Could u please take a picture of the area you think the problem is so we can see for ourselves? An exhaust leak is normally seen with a ton of carbon build up around the leak. When the stud backed out on my mani and the gasket went out, my head was nearly black and full of carbon soot. And even with 2 cylinders leaking exhaust gases, I was still boosting nearly 18psi on a 14b with no problems. It was just annoyingly loud under the hood because of the leak.