fuel cut (?) at 15psi

[green_GST]

The car I'm looking at getting, a 98 auto GST seems to be hitting a fuel cut at 3.5k/15psi. It has a FMIC, greddy BOV, and evo 3 16g, and it still has the stock MAF. (boost is set at 15 psi)

While test driving the car, I pulled it into low gear, ran the rpms out slowly and nothing happened, but at as soon I did WOT it kicked back really hard (the famous brick wall). I let up as soon as it did it, as it wasn't my car. Even though he told me to do it, just so I'd know what he was talking about.

Any ideas? Will an AFC and tune cure this, or would that just be a bandaid for the problem?

 

[silver bullit]

16g flows more than a t25 there buddy, you need a few more mods and injectors to do 15 psi on that turbo.

 

[MrBoxx]

You need to do a Boost Leak Test. Period.

Bigger injectors and an AFC won't do jack.

 

[Yngvar]

total noob here what is AFC

 

[MrBoxx]

An AFC (or S-AFC, or SAFC, or Apexi SAFC) is a piggy-back ECU tuning tool. It modifies the MAF/MAS sensor readings before they get to the ECU, thereby giving limited control over the fuel injection process.

However, in 99% of cases, fuel cut is caused by the MAF reading too much air passing through, due to a boost leak. This is why anyone experiencing fuel cut should do a boost leak test before anything else.

 

[Yngvar]

is an AFC better then a DSM link

 

[snowborder714]

No..

 

[MrBoxx]

is an AFC better then a DSM link

Not in the slightest. It's cheaper than DSMLink, but Link offers so much more than the AFC could ever hope to that they're not even comparable.

 

[green_GST]

16g flows more than a t25 there buddy, you need a few more mods and injectors to do 15 psi on that turbo.

I realize, that's why I asked if I needed an AFC to tune (injectors aren't necessary for this setup, I read?)

You need to do a Boost Leak Test. Period.

Bigger injectors and an AFC won't do jack.

Thanks! when I get the car this will be the first thing I fix/look for. I talked to the guy tonight and he said the coupler from the pipe to the IC on the "cold side" has a small tear in it...

 

[silver bullit]

Are your injectors stock?

Chances are yes. You need 650 or more the 16g can max the 450 or 550 out

 

[silverbullett]

Fixing all my boost leaks was probably the best mod I've done to my car and it was almost free. The car runs stronger and my gas mileage went up. Fixing boost leaks is definitely a win/win.

 

[twoTSis]

My FWD seems like it has fuel cut and I have it running on a stock turbo at 12psi and it has problems that seem to be fuel cut.

 

[twoTSis]

Fixing all my boost leaks was probably the best mod I've done to my car and it was almost free. The car runs stronger and my gas mileage went up. Fixing boost leaks is definitely a win/win.

Are boost leaks really that common on a well maintained car and how noticable is it?

 

[bento]

It's most likely a boost leak. 2g mass flows far more than 450hp. I haven't seen a 2g mass getting fuel cut. Do a boost leak test and go from there.

 

[snowborder714]

Are boost leaks really that common on a well maintained car and how noticable is it?

Boost leaks are common on all cars, unless you perform tests regularly and fix them. Do a boost leak test from the turbo and from the throttle body. It's easy to do and doesn't take a lot of time. Some leaks can be very noticeable (say if you blew a intercooler coupler off) and some may not be noticeable (say a small vacuum line).

 

[Defiant]

Fuel cut is not brought on by boost amount, but by the volume of air being drawn-in to the engine. If you start flowing more air than the ECU parameters deem safe for the engine, the fuel supply is cut off.

 

[GofaST4life]

old thread, i know...but i think i am hitting fuel cut...its all stock settings, boost, injectors, everything...

im going to build a boost leak tester using the link in the third post...

any advice before performing the test?

 

[kyleh]

yeah, dont pressurise it too much. Id stay at or below the psi you are running.

 

[GofaST4life]

well my boss didnt pay me today, so for the time being im just going to turn my MBC down all the way...

the DSM is starting to run me dry...esp with gas being 4.23 for 93 oct...

 

[da_golden1]

my car also hits fuel cut at 15psi in 3rd gear. I have 225 walbro fuel pump and it still hits. what i've heard is a good set of injectors and a good tuning device will solve this problem but untill then i'd run only like 10-13psi.