1999 S80 T6 engine stalling, rough idle, power loss

filichino · Post by **filichino** » 14 Apr 2017, 15:11

I'm having problems with car and I think its ETM related. I have an aftermarket Xemodex ETM installed in the year 2010 and the make and model is a 1999 Volvo S80 T6.

When the car engine is on and at idle, the rpm's fluctuate 100 to 300 rpms up and down.

Throttle fluctuation is noticeable at speeds slower than 45 MPH.

At times the engine completely stalls or comes close to stalling. This intermittently happens after coming to a full stop at an intersection.

At times the car seems like its lost power when I accelerate from a full stop.

With the engine hood up I also can hear what sounds like the throttle plate "flapping" or multiple small "thud" sounds when the engine is at idle.

I can drive the car at freeway speeds however at times the car seems to "surge".

I connected an OBD reader and when I map MAF sensor values with Throttle plate position values, the MAF sensor seems to be stable (the reading are consistent) but the throttle plate seems to go up and down in values inconsistently, this is true at idle and if i hold the accelerator pedal at higher rpms. The fact that I can read stables values seems to imply that the MAF sensor is doing its job and is working.

The OBD II reader that I used is a ELM327 bluetooth wireless connection combined with the Android app Torque Pro.

The engine is not misfiring and there is no CEL codes.

To try and remedy this problem I removed and cleaned the Xemodex ETM, I have recently replaced all vacuum line hosing, I thoroughly cleaned the PCV breather system and MAF sensor, changed spark plugs, all with no success.

If anyone can help me it would be much appreciated.

850TurboTurtle · Post by **850TurboTurtle** » 15 Apr 2017, 01:28

I'm replacing my throttle body module this week so I've been reading up a lot. One thing I've heard is that a gummy throttle plate can stick and then 'bounce' causing low and uneven idle. I tried cleaning mine with a special spray, got it really clean, but no change, so i'm moving on to a replacement bosch unit. Anyways, on higher mileage cars I have heard of people cleaning the throttle body on an S80 and it running fine afterwards. Youtube has a few videos on it for your era car. Good luck!

filichino · Post by **filichino** » 15 Apr 2017, 23:50

Can you send me a link on where I can purchase a Bosch unit?

Legofan · Post by **Legofan** » 16 Apr 2017, 09:52

Start the car and while it is rough idling disconnect the MAF sensor. If the engine stalls then it is not the MAF, but if the idle calms down then you have a bad MAF. I doubt it is the ETM.

Legofan · Post by **Legofan** » 16 Apr 2017, 09:52

filichino · Post by **filichino** » 16 Apr 2017, 12:34

Thanks for offering some help Legofan, I disconnected the MAF sensor while the engine was rough idling and the car completely stalled...

Legofan · Post by **Legofan** » 16 Apr 2017, 17:23

I read that to did some vacuum lines. It's possible you crossed lines on the TCV or it is not functioning properly.

filichino · Post by **filichino** » 16 Apr 2017, 18:51

Do you know where I can find documentation on vacuum line routing?

Legofan · Post by **Legofan** » 16 Apr 2017, 18:58

filichino wrote: ↑16 Apr 2017, 18:51 Do you know where I can find documentation on vacuum line routing?

It's on the hood, lower left or right

filichino · Post by **filichino** » 16 Apr 2017, 20:21

I'm having a hard time understanding the diagram, where is the "purge" located in the engine bay? And from the tcv where does the blue vacuum hose connect to? The intake manifold? Or the hard plastic intake hose connected to the ETM?