lyleswk

Not sure of the relationship with temp sensors and the ECU going into "limp" mode, maybe some others do. But yes, I would definitely replace the sensor because your fan is not supposed to do that. If the "green" sensor in the coolant flange doesn't solve it, try the one at the exit of the radiator ("black" sensor).

Le31504

Not sure its limp mode... cus it goes back to normal when driving...
Limp mode should only go back to normal when turning of car and restarting...

lyleswk

Others, please jump in if you know details, but I think the car will go in and out of limp mode depending on the state of the inputs to the ECU. What I mean by that is the ECU expects XX inputs from various sensors. If the temp sensor is one of those, then if it goes out of range (meaning voltage), it would go into limp mode. In your case, let's assume you have a flaky sensor that sends eratic or shifted voltages. If those voltages come back into range, the ECU will go out of limp and the car will run normally. Again, I don't know if this is the way it works, but it is feasible. Fix the sensor and see if that changes anything.

Le31504

no.. not that metallic like
Its more like a vibrating sound...
It could be the exhaust or something on it that vibrates on 3000rpm, and can only be heard when standing still en revving

Thanks

Le31504

Did the yearly Checkup yesterday and came out with clean papers... even better results then last year...

CO: 0,0
CO 2005: 0.0
HC: 000
Lambda: 1.01

Brakes L Front 3.2 R Front 3.2
L Rear 2.0 R Rear 2.0
(how even and how good the brakes works... brakepower vs car weight

Had no error codes (ODB2)
Dont know exactly what codes thay see or search for, but thay did not find any anyway

lyleswk

One comment and 2 questions:

1) All they look for in Texas is that you do not have a CEL. That would indicate if any of the codes the EPA has prescribed are operating out of range.
2) What state are you in? They don't check emissions in Texas.
3) Did the shop have any comments on the noise?

Le31504

Im from Sweden...

Dont know what thay check exactly, but thay connect to the ODB with an ODB Tool... did not ask what thay see (too bad)

The inspector did not notice any sound or something... that massure the exhaust readings at idle and at 3000rpm, but he did not react att any noise (and he

Even I cant hear that sound like before... either its gone or much lower than before

lyleswk

Wow, Sweden. Your English is much better than my Swedish and even my very broken Dutch. Anyway, wonder if they keep a record of the codes at the shop? I would think this narrows down the issues to something being "loose" somewhere becuase I would assume they would have discovered a running issue that would point to vacuum leak, misbehaving valve, cat failing, etc, etc. Maybe it is simply an exhaust hanger at the back of the car?

Le31504

thanks! we study english from about age of 8-9 here in sweden.. so the most of us can speak english quite good...


Well it could be...
They inspect the car on a lift and check all critical points and think that they would have seen if there was any problems under there...
And if there were any leak from exhaust it would have shown when they test exhaust fumes...

but as i sad earlier the noise is almost gone... cant really tell if its there or not anymore... Funny car :-P

But there is an new thing... When boost reaches about 1 bar i have som vibrations in the center vent or somewat in the center of the dashbord (inside car) and this is only when boosting and fades away after a few seconds... has nothing with rpm or anything like that to do...
And mostly when cold... less vibrations when warm...
Im not conserned about this but anyway...

Like i sad funny car :-P

lyleswk

I will say Audi are great cars and you will learn what noises are normal.

Anyway, your comment about 1 bar made me go back and reread what you are running. I realized you are running GIAC aftermarket, so all the other intersting discussion we have been having may have been for not. I have a stock 1.8t running in the 0.5 bar (7 to 8 psi) range. So, very familiar with the setup. But, if the noise has gone away, would leave her be.

By the way, did you ever do anything with the sensor to correct the fan issue?