Brick wall at around 4k

[turbo93tsi]

The car is a 90 tsi. Stock 6 bolt, Maf-t with GM 3", Dsmlink v3lite, some Turbonetics 50 trim, 1000cc (Fic's?), Walbro 255.

The car was running great, until yesterday.. Idle afr bounces between 14.2 and 15.5 (same, prior to current issue), great power up to about 4000 rpm and then all the sudden it's as if I'm hitting fuel cut. I assume this just from what I've read, I've never felt fuel cut before so I may be wrong. When this happened I think I saw the cel flicker for a second. No codes to be pulled from the ecu. Does it in every gear, and the boost gauge reads about 10 psi when it happens.

New plugs were put in a few days ago, I swapped the wires with a set of known to be working ones. I'd grab a log if only the damn battery on my laptop weren't completely dead. If anyone can lend a hand with why they think it's doing this, it would be greatly appreciated. I haven't done a boost leak test yet, I know this should be number one on my list. It's my brother's car and I had minimum time to troubleshoot.

Thanks

 

[eclipse420ags]

My guess boost leak.

 

[thecman02]

If you have two step or antilag I would assume its hitting that which makes me think your clutch switch wiring isn't right. I'm just throwing a guess out though because without a log no one can really give you a good place to start looking. Get your laptop charged!

 

[turbo93tsi]

No 2 step, anti-lag not setup. Lol, battery dead, as in it won't take a charge anymore At what rpm does a 50 trim setup typically build full boost? My brother just got the car a couple weeks ago. Previous owner said it was tuned for 22 psi. I think the highest I've ever seen it was maybe 15 pounds. He got it with a bad maf sensor. I changed it out a few days ago, no codes, ran great. I think I'm gonna buy an inverter to power my computer in the car. I'll have another chance to do some more troubleshooting myself tomorrow morning. Until then, I just want to get an idea, or several rather on what to all check.

 

[bryanwheat]

Before anything do a boost leak test. There is a 99 percent chance that you have a boost leak.

 

[greddy_1700]

Wow, your car hit a brick wall and youre still driving it? Impressive (kidding, but your thread title sucks)

Boost leak test #1, but to me it sounds like it is your throttle position sensor on its way out.

Does this happen at full throttle, or part throttle, or both?

 

[T is for TURBO]

Fuel cut. As said above, BLT.

 

[Diamond Star Werks]

Dsmlink doesn't fuel cut. You have a boost leak, or fuel pressure too high, or you messed up your tune.

 

[T is for TURBO]

Dsmlink doesn't fuel cut. You have a boost leak, or fuel pressure too high, or you messed up your tune.

Hmmm... I did not know that, thanks for that info.

I'm still betting on a big boost leak. They can hit you like a brick wall, especially when you're not expecting it

 

[Diamond Star Werks]

Hmmm... I did not know that, thanks for that info.

I'm still betting on a big boost leak. They can hit you like a brick wall, especially when you're not expecting it

Boost leak on a stock ecu causes fuel, hence the brick wall feeling. Ecu reads airflow from before the turbo. stock Ecu has a preset airflow number for fuel cut. With a boost leak air and pressure is lost, the less backpressure there is the faster the turbo spins. So with a leak the turbo overspins trying to pressurize the intake, therefore drawing in more air. till it reaches the fuel cut limit, then bam! Fuel cut, brick wall feeling.

Without fuel cut boost leak will feel like hesitation, stuttering, sluggish boosting, loss of power.

Sorry rambling info post.

 

[T is for TURBO]

Boost leak on a stock ecu causes fuel, hence the brick wall feeling. Ecu reads airflow from before the turbo. stock Ecu has a preset airflow number for fuel cut. With a boost leak air and pressure is lost, the less backpressure there is the faster the turbo spins. So with a leak the turbo overspins trying to pressurize the intake, therefore drawing in more air. till it reaches the fuel cut limit, then bam! Fuel cut, brick wall feeling.

Without fuel cut boost leak will feel like hesitation, stuttering, sluggish boosting, loss of power.

Sorry rambling info post.

Not rambling I understand how and why fuel cut happends. I just didn't know dsmlink removed it. I just remember going to pass some one, I was at full boost in third gear, and I popped an IC coupler and it felt like hitting a brick wall. This was with DSMLink 2.5. Felt just like fuel cut. Granted I know it was just due to the sudden loss of power. Other than that time I never drove the car with a big enough boost leak to hit fuel cut. But I always assumed it was still in the programming. Good to know though