1G TSi fuel cut at full boost

[TurboJunky]

I drove a TSi the other day that I'm looking at buying, and experienced a small problem.

Under hard acceleration, as soon as it reaches what seems to be full boost (~17psi at the moment) fuel cuts, and it feels like someone just jerked the ebrake. The car will recover and continue to accelerate until it reaches full boost again, then the same happens.

The car has an Apex'i SAFC installed, and the battery died in the garage not too long ago. Would it be possible that this has been cleared out? Would that cause the symptoms?

The owner's father also made aware to me that the inlet hose to the intercooler was split, possibly causing a boost leak that would cause the same symptoms.

At any rate, I'll be purchasing the car in the next couple of days, as I feel this would be an easy problem to resolve with some simple troubleshooting.

Forgive me if this has been covered a million times, I'm a DSM newbie and just want to know what the easiest route to follow was.

Also, if anyone has an SAFC programming "guide" or the Apex'i original manual in electronic form, please send it to me at [email protected] or on AIM at e30matt. Thanks guys!

 

[Generation1JeY]

without aftermarket fuel equipment (pump, injectors, fpr, afc) or a larger than stock Intercooler the boost should not be passed 15psi.

If he has all stock fuel system with stock intercooler then turn the boost to 15 psi, and if it still hits fuel cut then u have got a bigger problem. But 17psi is too much for the stock fuel system and intercooler.

What intake modifications does he have? upper intercooler pipes? modified intake parts will make the car flow more making fuel cut come quicker than usual, but at 15psi u shouldnt be getting it.

is it really cold where u live? if its really cold out u might hit fuel cut a little sooner than when its warm outside.

 

[TurboJunky]

It's got a bigger fuel pump in it, as well as bigger injectors... stock FPR though, but he's got an AFPR and a set of lines that are going on as soon as I get the car.

He's got an intake, hard upper and lower intercooler pipes (still on the sidemount, he has a Starion FMIC waiting to be installed), and a Greddy Type S BOV.

According to him, the car ran fine at between 17-19psi, and this problem has happened before.

I was thinking the first place to go would be the split hose on the upper intercooler pipe.

 

[Quasimondo]

The split IC hose the problem. If it's leaking bad enough, then your turbo is spinning a lot harder than it needs to to reach 17psi because of the boost leak. Your MAS will see much more air than what actually reaches the intake, or what your boost gauge will see, and is seeing the equivalent of 20+ psi. Fix the hose, to seal up that boost leak, your turbo won't work so hard and your fuel cut issues should disappear.

 

[TurboJunky]

What type of hose should I use to replace it?

 

[Quasimondo]

Replacement factory hose. There's another thread in the General forum about using radiator hoses as well. As a temporary fix, you can probably just duct tape it up and turn the boost down to under 15psi.

 

[TurboJunky]

Can I use the radiator hose for a coupler such as this? Noone seemed to think it would cause any problems.

 

[steve]

Can I use the radiator hose for a coupler such as this?

Sure it you can find the right size, it will work.

Steve