'04 S60 2.4 Engine retard code

[RussB]

I've had the car on the road for 2 days...

As I try to accelerate hard, the engine management system retards the timing and throws a code (my Volvo code reader is in my other Volvo which is in the shop!), making the car sluggish...kinda feels like its hitting the rev limiter even though I'm no where near redlining it.

The car has a significant exhaust leak that I have not yet examined.

Ideas? Wild guess'? Been a while since I last visited. Hope all are well

[abscate]

Timing gets pulled way back when boost comes on. If the turbo control valve gets tired I wonder if the two don’t stay in synch?

Wild guess on my part.

[RussB]

No turbo, it's a 2.5L B5244S. It feels as if the exhaust is clogged. Again, there is a significant exhaust leak, but weather is deteriorating fast here so I have no opportunity to look at it. The intake is clear of debris, the air filter and plugs are new (Volvo branded plugs)

The car runs great otherwise. Starts fine, idles fine. It'll easily go 80mph on the highway...just won't pull while passing or going up a hill. It just kinda "gives it up". I have a great local shop called Re-Volv. They have all the cool toys to diagnose the car.

[RussB]

My mechanic checked out the car and also found the P420 code. That, along with the swishing sound it makes when you get on it points to a clogged catalytic converter. The computer is actually trying to "save" the engine by retarding the timing!


So...Who has tried a complete Borla exhaust system?

[RickHaleParker]

That, along with the swishing sound it makes when you get on it points to a clogged catalytic converter.

Don't be too quick the blame the Catalytic Converter. A clog anywhere in the exhaust system can produce the symptoms. It could be a clogged Resonator or a clogged Muffler. It could be some smart-ass stuck a potato up the tail pipe.

To determine if there is a restriction in the exhaust system is to remove the front O2 sensor. This will release back pressure.

• If the problem goes away, there is a restriction in the exhaust system.
  If no change you got problems elsewhere.

Reinstall front O2 sensor.


Open the exhaust system between the Catalytic Converter and the Resonator by removing rear O2 sensor.

• If the problem goes away the problem is downstream, Resonator or Muffler.
  If the problem does not go away the problem is upstream, Catalytic Converter.

Reinstall rear O2 sensor.

Remove Muffler.
If the problem goes away, the Muffler is clogged.
If the problem does not go away, the Resonator is clogged (1).

(1) Keep in mind there could be material from the Resonator stuck in the pipes.

[RussB]

That's great advice! Thanks

The exhaust system on this car is original and in poor condition. There are leaks/holes in the muffler already.

[oragex]

How many miles on it ? The exhaust will leak at the flex down pipe - needs replaced along with the cat because welded together, perhaps Rockauto has something. Don't try to remove the studs in front of the down pipe, just put new nuts. After the cat you will have to drill the studs. Then you need rear brackets. The end pipe also can break off the muffler - just reweld. Aftermarket rear mufflers are really either short lasting or too expensive, best way is to get used one off Ebay from places like Florida or South states

When does it start to bug, close to 3500 rpm ?

[Supergrunged]

Just hit up Nick at Re-Volv for a bigger downpipe, and just redo it