Full 3 inch exhaust system causes fuel cut?

[whiteturboz89]

Sup my fellow supra brother n sisters,

i tried searching but no results that poped up in the search thread. i recently just installed a 3inch elbow/downpipe to 3 inch testpipe and catback all the way. in 2nd or 3rd gear once my car hits about 5.5-6k rpm my check engine light comes on and it feels like my car loses power for a couple of secs. i believe this is fuel cut? i've never seen my stock boost gauge sky rocket to the roof before. i know the stock gauge isnt accurate but i know for sure i gained psi " just dont know much ". Iam going to need a tune? it felt like i lost some low end torque but top end is diffidently more powerful.

Mods i have Hks intake, Hks intercooler kit/ pipes, and full exhaust system. need tune?

i apologize if it seems like such a newbie questions i have seen plenty of newbie/dumb questions and i know some get annoyed. believe me i tried searching.

U guys have a good day and thanks for your time -.-

 

[Grandavi]

You didnt by chance shim the wastegate? I had that problem with my 87 GTE because the waste gate was shimmed. But the red light didnt come on. Should check for engine codes.

 

[Poodles]

Fuel cut with feel like a serious lurch when it kicks in.

Quite possible with the mods, but I'd check the wastegate can swing open all the way.

 

[jake8790]

Check to make sure the wastegate arm and flapper aren't hitting the downpipe.

This is fuel cut: http://www.youtube.com/watch?v=NTZUkyGBq-Q

 

[IndigoMKII]

I know by changing out my stock downpipe with a full 3" downpipe I hit fuel cut at 4500 rpms on the ct26 57 trim.

 

[radiod]

I know by changing out my stock downpipe with a full 3" downpipe I hit fuel cut at 4500 rpms on the ct26 57 trim.

Same here....it's not uncommon once you get more air flow through the intake and less restriction after the turbo, especially at sea level and with cooler weather.

 

[57trimMKIII]

Fuel cut with feel like a serious lurch when it kicks in.

There are different "extremes" of fuel cut IMO. For example, right now I'm experiencing the same thing as the OP (with similar mods - intake, downpipe, test pipe, cat-back). Sometimes (and only sometimes) when shifting from 2nd to 3rd (auto), my car will throw a CEL and cut out for a second - I call this "baby fuel cut." Now when my wastegate was disconnected (for testing), I felt the "serious lurch" you're speaking of which I call unforgiving fuel cut. :bigthumb:

 

[Dan_Gyoba]

"losing power" is kind of an ambiguous term.

I've only felt FCO in my car once, and that was quite the experience. I thought for sure something had failed. It was only after fuel was returned, that I figured out what happened from others' descriptions.

Probably a different experience in a standard (Going from WOT acceleration to engine braking) than in an auto, where it's probably more like letting off the throttle.

I had a boost leak that felt like the engine losing power. It was running so damned rich that it was barely making any power at all, which felt really wrong. The large clouds of black smoke out the tailpipe were the clue there.

With the CEL lighting though, that's probably FCO. Check stored codes in the ECU for confirmation.

 

[radiod]

There are different "extremes" of fuel cut IMO. For example, right now I'm experiencing the same thing as the OP (with similar mods - intake, downpipe, test pipe, cat-back). Sometimes (and only sometimes) when shifting from 2nd to 3rd (auto), my car will throw a CEL and cut out for a second - I call this "baby fuel cut." Now when my wastegate was disconnected (for testing), I felt the "serious lurch" you're speaking of which I call unforgiving fuel cut. :bigthumb:

It's all the same....just feels different depending on how hard you are accelerating and how fast you are going at the time. If you are unsure if it is in deed fuel cut or not, check you codes and look for code 34.