Buck under heavy acceleration

[chuckstsi]

Whats up? New here to this site and its great. Not so new to DSM's though but I'm having some trouble.

Under hard acceleration, from 3rd up, the car will give me a buck then continue to pull fine until I grab the next gear and I get the same thing. This is not every tiime but more often than not. First and second pull smooth.

Checked the norm, no boost leaks, changed plugs and wires. The car otherwise runs like a champ..I'm kinda stumped...

At first I thought maybe the clutch, but its an ACT 2200 and its new. But even then I figured I would slip in first and/or second...

Thanks for any help!

 

[gtbread77]

What psi you running that 16g at?At what rpm do you feel the bucking?? Any other mods to the car???

Also it's a ACT2100 or ACT2600 clutch just fyi

 

[Imback]

OP fill out your profile so we can get a better idea of what is done to the car

 

[chuckstsi]

Sorry guys, the profile is correct. I purchased the 16G as a replacement. Never did anything else to the car. That turbo has been in the car for probably three years now. Act 2100 is correct, my fault. Never really noticed what RPM, but I'll be sure to look.

I've been doing a lot of reading for some future touches to the car. I'm splitting the wallet between it and my 69 Camaro...so any thoughts would be appreciated.

 

[Dert]

What kind of plugs and at what gap are they set to? You will want ngk's BPR6's capped at .028


Sent from my iPhone using Tapatalk

 

[dsm03]

Exhaust Gasket? check the the where the downpipe connects at the front of the vehicle.. also, as mentioned Spark Plugs,

 

[my dreamt dsm]

You are either starving your injectors or have a very big leak after the exhaust manifold between the exhaust housing. Another thing to look at is the front o2 sensor.
I don't know when a 16g kicks in but are you also buckling at that rpm?
Another thing to, I guess your having problems with is you can hear your turbo spooling but your not going anywhere?

 

[BigBeans]

Exhaust Gasket? check the the where the downpipe connects at the front of the vehicle.

It's not that.

It's most likely an ignition issue. It could be spark blowout, or it's possible that it's a fuel/airflow issue but that's a lot less likely if it pulls clean from spoolup onward.

 

[Dert]

Another thing as mentioned is you are running out of fuel, change pump to at least 190lph and it may help, but you will most likely be overrunning your injectors too


Sent from my iPhone using Tapatalk

 

[ty92dsm]

Check your ecu to make sure the capacitors haven't leaked all over the board

 

[chuckstsi]

Sorry I'm confused. Other than the 16G which is controlled by the ECM, the car is stock. How could I possibly be having fuel issues? I dont really hammer this thing at all. The only thing I can think of is maybe the stock pump is not doing the job it used to?

Just put new plugs and wires in as a first resort. Wouldnt I see misfire codes?

Dont mean to question you guys, just trying to learn...

 

[ty92dsm]

Once again......check your ECU. Do you have a boost gauge?

 

[chuckstsi]

Ok I can check it, got to do a front wheel bearing tonight. Yes I do have a boost gauge, is there something specific I should look for?

 

[kchaazz]

What kind of plugs? You should be using NGK BPR6ES at .028 gap. Stay far away from iridiums and platinums, they are crap for these cars. Ive had the issue youre having before. Check the plug wires at the coil and make sure theyre all plugged in all the way. In fact, pull em out one at a time, and reinsert each wire into the coil; you should feel a "click" as the fitting snaps into place. Of course, this is assuming you have no boost leaks. Personally, Ive had MASSIVE exhaust leaks as a direct result of using the wrong grade bolts in my turbine housing and the car never bucked once, so Id look to ignition first, which is easiest, then boost leaks, then test your fuel pressure, change the fuel filter; if the cars been sitting a long time, Id pull the plug on the bottom of the tank, drain it, and put in new fuel; youd be surprised to see how nasty the crap in the tank can get!!

 

[2g2ner86]

Possibly fuel cut??

 

[ChiTownHussla]

Agreed

Possibly fuel cut??

 

[chuckstsi]

Ok ill go over the plugs and wires again, thanks for the suggestion.

Fuel cut? Can someone explain this a little deeper?

 

[ty92dsm]

What is your boost set at?....is it holding it or is it creeping? Basically fuel cut is when your MAS sees too much air being pulled into the engine, therefore it cuts off fuel supply to prevent blowing your car up, you will know when you hit fuel cut it is quiet violent. You will usually hit it somewhere around 18psi but it is there for a reason because the stock fuel system cannot handle much more than that with doing damage to your engine.
I don't know if that was a good enough explanation but I tried

 

[chuckstsi]

Boost is factory controlled. It doesnt go over 15psi.

 

[ty92dsm]

Hmm well when I first got my car it hit fuel cut and stock acuator it was like 8-10 psi. I couldn't figure it out, I put a 190 in, fixed all of my boost leaks, everything possible and it still did it. Come to find out my ecu was junk so I replaced it and it ran like never before