New catalytic converter

[AaronsVolvo]

Well it looks like my wagon may need a new catalytic. I was hoping it wouldn’t but I think it’s gonna need it.
It’s giving code po420 plus a check engine light.
The previous owner figured it would need it and didn’t want to spend the money on a new cat...

It’s a 1999 v70 base model non turbo. It only has to pass emissions for another few years, I don’t really want to spend the money on a new Volvo catalytic because it’s not really needed on this car, plus I have a lot more maintainable to do in this car.
Spark plugs, PCV system, trunk lock, gear shift light, plus whatever is causing the cigarette lighters to not work, at least one new front wheel bearing...
And that isn’t counting what I have already done LOL.

What I was looking to do was just ordering a catalytic online then finding a repair shop around here to do it(I have two lined up already who can do it).
My question is, what do you guys recommend as a replacement that will last the next 5 years plus what accessory parts will I need?
Rear O2?

Thanks in advance!

[oragex]

I don't know on cars prior to 2000, but on the models after 2000, the inexpensive aftermarket catalytic converters have a good chance to trow a check engine light from the downstream O2 sensor because they lack of efficiency compared with the original Volvo converters. While there, you may also want to check the downstream O2 sensor first, before replacing the converter. If thinking of replacing the converter, I'd go to a garage and do an emissions test. Also good to know that the converter usually goes bad from poor fuel mixture burning, so a replacement converter may also go bad if the problem is not fixed.

If replacing the converter, I would definitely go with a used original Volvo one.

[abscate]

They rarely go bad, and certainly that code is not enough to replace it.

Check for vacuum leaks, exhaust leaks, fuel pressure, compression before digging into the cat

[RickHaleParker]

Before you go replacing a expensive catalytic converter, it could be air leakage in the exhaust system or damaged injectors.

V70 (-00), 1999, B5254S Denso.
ECM-4201 (P0420) Three-way catalytic converter (TWC) efficiency. Power deterioration

Diagnostic trouble code (DTC) information ECM-4201

Condition
After start-up, the engine control module (ECM) checks the efficiency of the catalytic converter by switching between rich and lean fuel/air mixtures. When the change-over is made, the signal from the rear heated oxygen sensor (HO2S) is checked and the time taken for the probe to switch. The diagnostic trouble code (DTC) is stored if the engine control module (ECM) registers that the rear heated oxygen sensor (HO2S) switches too quickly.

Substitute value
None.

Possible source

• Air leakage in the exhaust system
  One or more damaged injectors.
  Damaged catalytic converter.

Fault symptoms
Malfunction indicator lamp (MIL) lit.

[AaronsVolvo]

Okay so how would I check for damaged injectors?
One thing the car occasionally does that I have attributed to old spark plugs is occasional hard starting, I’ll start the car and the RPM will jump then dip down to like 450 then rise back up to idle speed. It only does this on startup, not every time either.
Could this be injector related?

[RickHaleParker]

First do this:

• 1. Pull the electrical connector off the injector.
  2. Inspect the connector and wiring make sure the wiring is not damaged and contacts are good and clean.
  3. Measure the resistance of the injectors, it should be ~ 13.8 Ω at 20°C
  4. Start the engine and listen to each injector with a mechanic's stethoscope, they should be clicking like clockwork.

Beyond that you need to take them to somebody that has the equipment to bench test them.
You could just go to eBay and get a set of five remanufactured injectors.

[AaronsVolvo]

Okay I’ll do that next and test them out. Thanks

I changed the spark plugs this morning, it’s got a bit more power now but still after around 50mph it’s not revving past 3-4 with the pedal to the floor.
I’m also going to change the fuel filter in the next day or 2.

The check engine light hasn’t come back on yet, I’ve done around 50-60 miles since the reset, around 5-6 start cycles.

[RickHaleParker]

Will it rev past 3-4 when in park? Let it idle for 10 minutes before trying.
Do this with the windows rolled down and ears wide open.

[AaronsVolvo]

Yes I can rev it to the red line in park or driving lower speeds just fine. It’s only when I start to get up to about 50mph that it won’t go further.

I can get the car to go quickly, once I got it up to about 90 but I had to wait a while for it to get there.

[abscate]

If you reset the code, how long does it take to come back? Are there other codes?