'04 S80 - No acceleration

GTinsdale · Post by **GTinsdale** » 12 Jun 2013, 19:52

This one has me and a half-dozen Volvo specialists stumped. The problem is simple: when I step on the gas, the car has virtually no acceleration. At low RPMs, the car is fine. But when I punch the gas pedal when climbing a hill or trying to pass, I have NO power. I also hear this rather odd, low roar from the engine. And if I punch the gas pedal for more than 15 seconds, I get a message "Reduced Engine Performance," and the car has no power whatsoever for several minutes.

Here's what I have done so far with none of these yielding any change:

- Replaced the MAF sensor
- Checked the catalytic converters for obstructions
- Replaced the fuel filter
- Replaced the spark plugs
- Replaced the air filter

At first I thought it was a bad ETM but I don't have any of the symptoms of a failing ETM. I also thought it might have been a bad fuel pump, but, again, I don't have any of the symptoms of a failing fuel pump. As I said at the outset, I am stumped.

Any help would greatly appreciated.

Best, GT

Post by **jimmy57** » 12 Jun 2013, 21:48

Bad torque converter needs to be on the list.
If the stator support doesn't let stator in the center of TC freewheel it will be like you all of sudden have heavy trailer stuck on the back of car at 2100-2400 rpm.
Usually the trans fluid temp will go really high too if you drive it in the strain for very long.

The stator effectively ricochets the fluid from turbine back to impeller when the engine vs trans input shaft speed is different, in this case below 2000 rpm with unlocked TC clutch. When the engine speed is above that the slip is minimal and the fluid pumping between impeller (fan part of TC driven by engine) and the turbine (fan on the trans input shaft) is nil then the stator is effectively in the way of spinning fluid and acts as a brake. Even with locked TC clutch the stator must turn. When TC is multiplying torque the stator gets fluid pushed against it and it changes the fluid direction so it enters impeller at the proper angle. The freewheel in the stator hub holds the stator stationary in this case.
Stator that doesn't stop gives AWFUL low end and slow take off with normal behavior at higher engine and road speeds. Seized stator gives normal take off but makes engine labor like mad at higher engine speed.

rerobin66 · Post by **rerobin66** » 12 Jun 2013, 21:59

yeah....what he said:)

GTinsdale · Post by **GTinsdale** » 12 Jun 2013, 22:17

Jimmy - I think you're on to something. Everything you describe sounds like the issue I have. I've got a mechanic looking at the car first thing in the morning. I'll print out your response and show it to him. You may have saved me a bundle in diagnostic charges. I'll report back tomorrow.

I can't thank you enough.

GT

GTinsdale · Post by **GTinsdale** » 22 Jun 2013, 20:19

Well, after all's said and done, the problem turned out to be the rear catalytic converter. It was badly clogged and the car was unable to exhaust. The front cats had been checked and they passed with flying colors. I would have checked the rear cat were it not for the fact that the service manager at the Volvo shop I took the car to insisted, "I've never seen a rear catalytic converter go bad on the S80." Well, I guess "never" is now officially over.

Thanks for your help on this!

GT

matt5112 · Post by **matt5112** » 09 Jul 2013, 12:20

What do you mean by rear converter?

I only see the twin converters, a resonator and muffler. Unless something changed in the newer models.

Resonators can cause similar issues as your described though.