car stutters/bucks at 4k rpms

[BoostKrazy]

The other night my buddy came over in his honda, and wanted to race, no sweat off my back, right? So we fired em up and go down the street (private road), we take off, 1st gear, my car hits 4k and starts shaking violently, bucking, stuttering.. take it home and it dies on me, jumped it, take cables off and it dies again.. as long as cables are on it stays running (battery, alternator, fuse, all brand new)

So heres what i did to my car before all of this happened.. it was running good, but i wanted to do some maintenace so i popped off my top IC pipe and was cleaning out my throttle body/manifold with BG throttle body cleaner, put pipe back on (pretty sure as tight as it was before i took it off)... hooked up my laptop to it (just to show my buddy what ecmlink was like, i dont know how to tune for shit yet) i dont think i changed any settings.. and i went down a steep ass curb (car is really low, it scraped all the way down the curb, pretty much almost got stuck bottomed out) obviously didnt mean to but might of tore an IC coupler?.. i dont know if any of these things would cause my problem, but car was running fine before i did these three things (only things i can think of that might cause my problems)..

Things you should know:
1:car is on t-25 with 750cc injectors 255lph walbro and dsmlink (un-tuned) i dont drive it much nor will i until i get bigger turbo and a tune (professional)

2: i have a major exhaust leak inbetween (stock) o2 housing and (3") DP but it was there before problem occured. Havent fix it because studs are too close to DP (thanks to stock o2 housing) and nuts wont tighten all the way, gonna install my 2.5" o2 with bigger turbo.

3: have not performed BLT yet, due to lack of tools, and i dont know when previous owner changed plugs, wires or anything else.. car was stock when i got it (130k miles) car now has 130,500 (maybe less) and is pretty modded now and rarely driven until im 100% done and satisfied

I might be forgetting stuff, i will update if anything comes up, thanks in advance

 

[Macspsi]

Car is going to run really sluggish with those injectors in un-tuned. They're could be many reasons why the car is acting like that. A 255 fuel pump without a FPR is not a good idea. T-25 with a 255 and 750cc injectors is also a no no. If you have the stock fuel pump and injectors I will put them back on until you can get the car tuned with a bigger turbo.

and do a blt. here's a link of how to make one http://www.dsmtuners.com/forums/articles-parts-fabrication/386650-how-build-boost-leak-tester.html

 

[snowborder714]

Car is going to run really sluggish with those injectors in un-tuned.

Untrue. As long as they're dialed in via link, the car will run like they're stock sized.

A 255 fuel pump without a FPR is not a good idea.

Correct. The car will still run normal, but it's not a good idea.

T-25 with a 255 and 750cc injectors is also a no no.

Explain that one to me. My brother is running 2150's with a T-25. The only issue with that combo is having an injector that you will never use to its full potential. But the OP said he plans on upgrading the turbo.




OP, you need to do a BLT, especially after removing an intercooler pipe. Get the tools (or find a local guy who has them) and do it. Might as well also pull the plugs and replace them, and possibly get some new wires if you have any suspicions about yours. Hopefully your timing belt was down around 120k miles or you'll have a bunch of maintenance to do.

You can also post a log for us to check if you have any tune issues.

 

[Slightlystoopod]

Was it backfiring at all? The engine could be flooded with fuel. I know when I installed my 850's, I started my car to see if it'll run and it wouldn't rev past 2.5k RPMs when it is untuned. it would just stutter at that point. (I know not the smartest and I was experimenting since I owned the DSM a month and a half and didn't know better. Its all good though) I also have a 255lph and I didn't have a FPR back then.

Maybe thats what could be the problem? Idk, im not an expert

 

[USAF 98 GSX]

Like snowboarder stated its not impossible to run the mods you have currently as long as you have your injectors tuned down. I would definitely invest in a FPR, since it is basically the last main component left in the fuel system. (Minus fuel rails, etc. etc.)

You did state that the car is not tuned with Link v3, so does that mean you just have it installed with no supporting settings inputted for your current mods?

I'd double check your Link settings and do a BLT when you can to assure your entire IC system is good to go.

 

[Macspsi]

Untrue. As long as they're dialed in via link, the car will run like they're stock sized.




Correct. The car will still run normal, but it's not a good idea.




Explain that one to me. My brother is running 2150's with a T-25. The only issue with that combo is having an injector that you will never use to its full potential. But the OP said he plans on upgrading the turbo.

I read this as, him not having a tune for the car at all. Meaning the car isn't tuned for the injectors, so therefore it would make the car sluggish. My friend had the same problem with his gst he had installed bigger injectors in his car without it being tuned and in result made the car slower. Took them back out put the stock ones in and the car ran strong again. but thanks for clearing me up im still learning and trying to help.

 

[3052Talon]

Sounds like it needs a tune! Are you running speed density with V3?

 

[BoostKrazy]

I do have an aeromotive fpr, not installed yet.

And i have been on V3 and tried to "calculate" my injectors but idk if it saved or even if i did it right..

I do have sd bundle, but like my fpr, it is not installed yet.

 

[snowborder714]

Post up a log as soon as you can so we can verify settings.