Wierd Acceleration

[DonnieD]

Hey guys,

I drive an 01.5 tip and I have just now noticed a strange thing that happens when I accelerate. I think I may be able to answer my own question but if it's true this the Audi engineers are retarded.

Okay, so when I first start my car I let her warm-up usually for a good 3-5 minutes. When I start driving, I'm very careful not to go into boost until my oil temp is at 175 (at least) so I basically granny accelerate until everything's good to go. Here's where I notice a potential problem: I apply a small, yet constant, supply of throttle. If I watch the revometer, it will sputter up and down as im accelerating. Best example I can give would be I am in 2nd and all the way from 800-2200RPM's the needle will inch up, inch down, then move up further in the range, then inch up, inch down, and move up slightly higher. The car seems to accerate relatively smoothly but I can hear the engine sort of going up and down slightly in tone as the RPM's are jumping up and down. When the needle is going up and down (and slow in the direction of moving upwards overall) the needle will only drop 100 RPM's then proceed to move up.

The problem goes away as I get past 2200RPM's in any gear. Change gears and it's same issue again. If I apply more gas then the needle is a steady increase and no sputtering, so, that's why I thought I could answer my own question. Maybe Im not supply enough gas BUT I know it's enough to actually get me going. Maybe 20% throttle if I had to guess. Any TIP guys have this same issue?

I have not changed my tbelt yet. Will be doing that in two weeks.

[B6JoeS4]

does the problem go away once then engine is all warmed up

[tbone5446]

yeah mine does that too, BTW you don't need to let your car warm up for that long.
It's actually better to let the car warm up while driving instead of sitting idle.

[Jung]

tachometer

engine speed sensor issue?

[DonnieD]

does the problem go away once then engine is all warmed up

Good question. I should know this because that's what i tested but I can't remember. I think the answer is No but I'll have to check it out when I get off work.

yeah mine does that too, BTW you don't need to let your car warm up for that long.
It's actually better to let the car warm up while driving instead of sitting idle.

I've only had the car for 2 weeks so Im glad I read this when I did! I swore I read somewhere that warm-up should be at least a few minutes.. I assumed that meant warm-up by idling. Can I start up and take off or should I at least sit a minute then go?

tachometer

engine speed sensor issue?

Thanks for the suggestions. I'll have to bring it in when I have time. I'm definitely prioritizing the Tbelt job right now.

[A62TURBO]

I've only had the car for 2 weeks so Im glad I read this when I did! I swore I read somewhere that warm-up should be at least a few minutes.. I assumed that meant warm-up by idling. Can I start up and take off or should I at least sit a minute then go?

I usually wait for the SAI motor to stop until I take off. Leaving your car idling for a long time is not great as far as wear and tear goes, but 3-5 minutes is fine.

[RocketSurgeon]

lol at revometer

[DonnieD]

lol at revometer

lol you can blame my use of this term on my wannabe mechanic friend. Revometer seems like a cute name tho, eh!

[RolledMySTi]

The problem sounds like you are just driving like an old lady and lugging the motor. You shouldn't normally be below 2k rpms in second let alone 800. At 800 rpms in second you are lugging the shit out of the motor.

[DonnieD]

lol alright, i'll try to put some youth into this foot and give it a little more gas. Im just overly cautious. My last question is, when do the turbos boost? I've read to shift before 3k RPM's but I thought i've also read they boost at 2500 RPM's. I appreciate the help.

[Jung]

it's not dependent on RPMs, but load on the motor. If you're giving it a lot of gas, you'll be boosting it. Do you mean to tell us that you have not invested in a boost gauge?! get the hell on that.
As STi said, you're really dogging it (800 in 2nd is almost below normal idle).
Why are you being cautious with it? This car is not meant to be driven like a 70 year old woman, give it some gas, let it go WOT every now and then. Drive it like it was meant to be

[haus4]

Its a TIP guys. Ive never driven in a TIP s4 before, but my guess is that either one of the speed sensor or the crank sensor that reads the RPM is going.

[00s4slvr]

na thats normal. I had an a4 2.8 before my s4 and it did the same thing. Even my cousins old a4 did it to. its something to do with because your shifting at a low rpm. Shift after 2500 and you wont have this problem and also dont granny it lol. If you wanna granny a car by a toyota corolla.

[DonnieD]

lol sorry for not clarifying guys.. I granny it until the oil temp is at 175 or higher and then I have a little fun.

[dak360rt]

I usually wait for the SAI motor to stop until I take off. Leaving your car idling for a long time is not great as far as wear and tear goes, but 3-5 minutes is fine.

x2

From what i have read its best to start the car ( the tach should read somewhere around 1100 rpm) idle till it drops down to 800 rpm, then drive. It is best if all the fluids in the car warm up together. And again no boost until 200 degrees