PDA

View Full Version : 3500-5k RPM slow acceleration?



Bvulic
10-15-2011, 09:04 PM
Hey, yesterday I was riding rather spirited down the highway last night, and it seemed as if I had very little power when accelerating hard. I was pushing the car pretty hard and it seemed nearly impossible to reach speeds past like 90 m.p.h. I don't know why but It never acted like that. Seemed as if all the boost wasn't being accounted for. Could this be a bad DV? That is my best guess. Am I on the right track? Thanks, and help would be appreciated.

Sidewayzracer
10-15-2011, 09:09 PM
what year car is it and do you have a boost gauge?

Bvulic
10-15-2011, 09:12 PM
Sorry, forgot to include that, its a 99.5 facelift 1.8t auto. I do not have a boost gauge installed, I was getting around to it but I've just been really busy with work. The car performs fine between the 1000-3000k rpm range. After that it seems very underpowered for some odd reason. Could this possibly be a bad DV? It's still the original DV and the my car has 92k miles on it.

Sidewayzracer
10-15-2011, 09:18 PM
it could be a bad dv or a vacumn leak i cant be certain but another option is to use a vag-com to log block 115 but this only is an option if your car does not have an AEB engine which has no MAP Sensor.

But lack of power above 3k rpm sounds like a lack of boost.

coolgraymemo
10-15-2011, 09:30 PM
Any codes?

It's kind of hard to guess exactly what's wrong with your car. No boost gauge? Are you sure you are losing power?

Get a boost gauge, and then report back.

Dynamite
10-15-2011, 09:33 PM
could also be a broken WG actuator, if this is the case then you will make boost very slowly and max will be about 2-4psi @5k or so.

Bvulic
10-16-2011, 11:28 AM
could also be a broken WG actuator, if this is the case then you will make boost very slowly and max will be about 2-4psi @5k or so.

I drove today, no codes at all no CEL, but i turned off the radio and drove it listening to the engine very closely and i noticed that when i let off the gas around >2200krpm, something flutters, as Im squeezing the accelerator, its quiet but once i let off it it flutters. Does this help at all? Thanks for your input.

Dynamite
10-16-2011, 01:37 PM
not really, the only way to really diagnose is to unbolt your exhaust from the turbo and put you finger up inside the turbo and find the WG and see if it is moving freely or not.if it is just flapping around then it will be the actuator. It should be closed tight over the WG hole. its a fairly common problem for them to brake at the end of the thread for the tension adjustment.

Edit, and forgot to mention, it wont throw a CEL or even codes. Dont know about the noise though sorry.

Dynamite
10-16-2011, 01:51 PM
oh and do a vac leak test, there are DIYs in the DIY subform. but if the idle is fine then its probably not a vac leak. To check you DV then pull it out and have a look if the membrane is torn or anything. none of them are big job, the biggest one is checking the WG probably half an hour if its your first time. take the electrical connectors and pipes of the air box and put it up on top of the ecu box, you cant get all of the wires off. then there are three bolts, from memory they are 15mm but not that sure on the cat to turbo flanges. with a wobble connector for and a socket or just a set spanner you can get the two top ones the bottom one is a bitch you have to jack the car up and get it form the bottom. then just push the exhaust back and put you finger in the turbo and the WG flapper is on the upper engine side. if you can move it there is something wrong.

Do this and if it is flapping free post back and I will walk you through fixing it. you have to pull the turbo. but you can do it for free, if you dont want to buy a new actuator.

Bvulic
10-17-2011, 06:59 AM
Thanks for the info, The idle is perfect, thats mainly why i ruled out a vac leak. I will most likely get to doing that next weekend, because Im busy with school this week. But yeah Ill take your instructions to heart thanks for your help. Ill get back to you with that. Honestly, I am shooting for the wastegate most likely because when i was under the hood, i was giving it enough gas for the turbo to activate, and once i let go of the throttle, i am getting a shuddering/fluttering from the wastegate actuator area for about a second until my rpms dip back down to 1000-1500k. I really wish I had a boost gauge just so I can know how much boost is being accounted for. :-(