surging problem as usual 02 s80 t6
 

After reading every post regarding surging power from the 02 T6 S80, I have concluded that I have one of two problems. The cause is either the turbo control valve on the outside of the airbox, or a spring in one of the turbo wastegate actuators. This known, How can I determine which is causing my surging problem.
The car surges under more than 1/3 throttle application - at any rpm. Fine at idle, though.

RE: surging problem as usual 02 s80 t6
 

Is the check engine light on?

RE: surging problem as usual 02 s80 t6
 

I recently had my 02 S80 t6 fixed with surging issues....it was the Turbo Control Valve, it is about a $75-$80 fix. It also only takes about 3 mins to fix from what I gathered.

RE: surging problem as usual 02 s80 t6
 

Nope, no check engine light. What does that mean? Will the spring breakage cause a check engine light? Thanks for the help so far.

RE: surging problem as usual 02 s80 t6
 

If it's surging and no check engine light is on....it is identical to the problem I had on my s80. Therefore it's the Turbo Control Valve...

RE: surging problem as usual 02 s80 t6
 

same answer, tech?

RE: surging problem as usual 02 s80 t6
 

Could very well be I haven't seen much of the Valves go. But that might just be the Florida market.
Does the check engine light ever flash?

RE: surging problem as usual 02 s80 t6
 

Nope, I have never seen the check engine light recently. valve huh. Florida is a similar climate to Hawaii, hmm.

RE: surging problem as usual 02 s80 t6
 

If the light was flashing that would mean Missfire.
I would say the Valve.

RE: surging problem as usual 02 s80 t6
 

turbo control module - replaced. problem solved. thanks for all the help.

RE: surging problem as usual 02 s80 t6
 

Tech:

I had my s80 non-turbo software updated, but since still have the surging issue. It surges when the car is hot after driving and putting it into park. When Park, the gas would go up and down until 2 to 3 times with rmp way low and stop the engine. It also surge UP when I slow down fast (not that fast), basically the rmp drops below 1000 and the engine would surge up to stop it from dieing (this is very dangerous at stop light and in parking lot. Once the engine is already hot, when I start it, it would also surges as just like putting it into park after driving. I basically have to put it in gear right away so the engine wouldn't die.

Now that I had replaced the air filter and spark plugs, I also had cleaned the throttle body 3 wks ago. The problem still exist. Before I took it in for the software upgrade, there was engine light that came on twice. But it had not come on since. I think the upgrade also kill the msg light so it won't report throttle error any more. Bottom line, it seems like the software upgrade was never done on this car.. what can I do now?

After reading this post (with the Turbo control valve), I have a feeling there is something similar to this with my non-turbo. Is it so? I know this is an air control valve just outside the air filter housing before the throttle body. Is this the same Control Valve this thread is refering to?

Also, since thisMOSTLY happens after the engine is hot, then put into park, Is this such thing as Evaporator valve or something like that? I have a feeling it must has something to do with the air-fuel mixture.

Beside, this engine is completely computerized, there's no such things as timing adjustment, or manual rpm control is there?

Now that my wife is driving my baby in this car, I'm really worry about stop light and parking lot mishap.

RE: surging problem as usual 02 s80 t6
 

TAKE IT BACK TO THE DEALER.
Complain about it as much as you can.
Make them drive with you and show them what it is doing.
It might be the throttle body itself bad.
They should replace it for FREE if it is bad.(in the U.S. market)

RE: surging problem as usual 02 s80 t6
 

Just what I thought could be a problem. But I have a feeling this won't be the end of it.

Took it to dealer this morning, just got a call from them, said that the Mass Airflow control is bad. I was considering replacing it myself since it's so easy. But was told that the computer need to be reset after replacement (IS this true??) which would cost me money to bring back for that anyway.

Costing me $200 for diagnostic + $350 to replace, still waiting for them to call me back. I just hope my surging problem goes away after this. Matter of fact, I hope they find faulty ETM so my mightmare would stop. I just have a feeling ETM on these model going bad is a matter of sooner or later.

RE: surging problem as usual 02 s80 t6
 

Well, well, well.. I just noticed all those engine surges changed my driving habits. Since it surges before, I was always aware and react different at stop lights and in parking area. I actually forgot how nice the car was until now. Without the surges, I found my self bracing for nothing (it's a weird feeling).

So, $548 is gone, with mass airlow meter replace, and ECM "reset fuel trim adaption". The Surges are GONE. The RPM needle stay in one spot. Wow, like I said earlier, I forgot how good that felt. [still doesn't change my feeling about spending so much money and other problems for a car with only 45K miles).

I had the feeling the air fuel mixture ratio was issue, and so it was (I have a little mechanical background). This was also why my car felt like it was loosing power (in the other thread). It seems this also resolved the loosing power issue with my transmission for me (just picked up the car, so I'll update later if power issue still there, but I think it's gone).

According to the report, they took out the "ECM to reset fuel trim adaption". I was wondering if this was necessary. If it's not necessary, this Mass Airflow Meter can be easily replaced at home for much cheaper.

A little more technical info from the report. "Found no codes sotred in system. Monitored ETM using VID. Found reading normal. Checked mass air flow sensor readings. Found readings very high, 25 kg/hr at a steady 640rpm. Repaced mass airflow sensor and remove engine control module to reset fuel trim adaption. Reinstalled ECM and rechecked mass air flow readings. MAF readings are now normal at 14kg/hr. Vehicle now idles smoothly. Road tested to verify proper operation."

Okay!, now that's just the engine. They also gave me a list of suspension issues require work. I will continue my other threads on these issues. Thanks again Tech.. and others.

To the initial poster: Your Air control valve with Turbo model and this Mass airflow metter for non-turbo seems to have a link with the surging problems. I hope this will help others trying to save some money w/o taking it to the dealers. As you can see, $548 at the end for a Mass Airflow Meter replaced is painful for my pocket.