high rpm problem

[lnvisiblejon]

this is my first post on dsmtuners but ive been a member for awhile now and ive ran into a problem that i have been unable to find a solution for. so here goes i have a 93 talon tsi fwd AUTO w/ 16g 720cc injectors, 255 fuel pump, afc neo, greddy TT and boost controller. im running stock intake & exhaust and stock intercooler setup. when im at 100% throttle i hit 15psi than it drops down to 9psi and holds there. while the rpms climb around 5000 the car jumps and it feels like im about to get whiplash from the car doing this so viently. i had my car worked on by garry marsh at speed injected and yesterday we spent a couple hours with the car on the dyno and we were unable to resolve the problem. he said he never ran into a problem such as this one. we put new spark plugs in tried new wires still nothing. he advised me to ask around on the forums for furthur help. im gonna be doing a boost leak test today aswell. could it be possible that my intake or intercooler are being overworked for the amount of boost being supplied? are there any other trouble points i should double check?

 

[v2ner]

Your intake and IC should be fine at the boost level. I'd swap in EVO injectors or 2G injectors just to see how it would react. Boost leak test is also a good idea.

 

[Street_Killer]

Sounds like your hitting the brick wall of fuel cut. Somone more experienced is gonna have to tell you why.

 

[lnvisiblejon]

yeah i thought it was fuel cut aswell, but dont my fuel mods come into play than? the shop also advised me to get a fuel pressure regulator or a fuel cut defender. im in the process of doing a boost leak test right now.

 

[v2ner]

yeah i thought it was fuel cut aswell, but dont my fuel mods come into play than? the shop also advised me to get a fuel pressure regulator or a fuel cut defender. im in the process of doing a boost leak test right now.

Fuel cut is a good thing. It's their for a reason, to save your motor. I wouldn't get a fuel cut defender without a logger. What color are your plugs?

 

[ChunkyLover53]

If you are still on the stock FPR, you need to upgrade ASAP. The stock FPR can not handle the pressure from that fuel pump. The highest you should go on the stock unit is the 190lph. I don't think this is causing the problem you are having, but it is something you should get done.

 

[v2ner]

If you are still on the stock FPR, you need to upgrade ASAP. The stock FPR can not handle the pressure from that fuel pump. The highest you should go on the stock unit is the 190lph. I don't think this is causing the problem you are having, but it is something you should get done.

Even a 190lph will overrun it. It's not a big deal unless you're fine tuning.

 

[lnvisiblejon]

If you are still on the stock FPR, you need to upgrade ASAP. The stock FPR can not handle the pressure from that fuel pump. The highest you should go on the stock unit is the 190lph. I don't think this is causing the problem you are having, but it is something you should get done.

yes im on the stock FPR. After I finish the boost leak test and find/fix any leaks ill throw on an aftermarket FPR and see what happens. would the stock FPR cause boost pressure to fluctuate? I still have some tweaking to do with the greddy Profec B Spec 2 thats gonna be a pain in the ...

 

[Turbo Talon 111]

I don't know about the Neo, but the last time I checked the biggest injectors a SAFC II could handle was 550 or maybe slightly higher but not 720. I can't tell you if that is your problem or not but it seems like maybe you are getting too much or too little fuel. Did you hook up a wideband while on the dyno and do some tuning? You may want to call up Apexi and see what they say as far as how big of injectors you can run on the Neo. Can I ask why you went with 720s in the first place? The seem like a bit of overkill for your mods.