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CA SMOG FAIL: High HC @ Idle Only

The Bosch reman's are good, that's about all I'd trust other than 'genuine' stuff. Don't think NTK makes AMM's.

Idle speed isn't really an issue, not adjustable, and 772 is right on spec where it should be.

If the cat was hot and it wasn't using all the available O2, I'd venture that it's done, especially since you'd mentioned high mileage. That said, the AMM/O2 are a good route to start. You can also swap in whiteblock white injectors with a resistor bypass. They are just a hair larger but a better pattern and have helped a few friends clean up some idle issues. Cheap upgrade while still looking stock.

Zach is right, gotta wait for the LH box to go into closed loop before the O2 will cycle normally. If it's not cycling when warm, yeah, it's junk. Or swap for new and not worry about it for a long time.
 
"new" rebuilt Bosch III type injectors installed. They're a more modern Bosch type injector, of the same flow rating as stock, and still Low Impedance. It was a drop-in solution. The car seems to start and idle smoother, but it's all placebo now.

I'll swap over the new BOSCH (Sorry Gsellstr, it was a lot easier to find) likely today.

Remanufactured "Genuine Volvo" AMM coming from FCP... Will try again after that.
 
its the cat, i went through chasing my tail on my typhoon with the exact same symptoms and pretty much the exact same HC readings. i found all kinds of random issues with the car after i sniff tested it, i went through every single thing i possibly could on the car, replaced the dizzy, icm , had the injectors rebuilt, replaced the leaking intake gaskets, every vacuum hose on the car etc. took it back for the test and it still failed with high idle hcs. swapped in a cat from another typhoon that had really low miles on it and it passed immediately
 
I'll see what I can do for a fuel pressure gauge. FPR wasn't leaking when I last checked it.

Still focusing on AMM for now. I still have a 1-2-1 CEL which won't go away, so it makes sense that the AMM is bad.
 
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Readings from the smog point right at a cat to be honest, as Erik mentioned as well.
You said you installed Bosch but didn't say what? On the O2? Eh, it'll work, life is a lot better, mileage and performance improved on the NGK/NTK O2, which I could find easily at Orielly and a few other chains, online from Summit, etc.
 
gsellstr said:
Readings from the smog point right at a cat to be honest, as Erik mentioned as well.
You said you installed Bosch but didn't say what? On the O2? Eh, it'll work, life is a lot better, mileage and performance improved on the NGK/NTK O2, which I could find easily at Orielly and a few other chains, online from Summit, etc.
Click to expand...
Yes, I meant to type O2 sensor.

I may still need a cat, though I still have a CEL for a Air Mass Meter, and have identified a potentially related misfire at idle. I want to get that sorted, as it's a now a drive-ability concern and I won't pass with a unresolved CEL.
 
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Volvo remanufactured AMM installed, Bosch O2 sensor installed. Oil & filter changed....New injectors were installed a few days (?) ago.

CEL is gone.

Idle is still funny, up & down. Seems to mis, hit fuel cut in boost...only drove around the block.

When the idle was wandering, I pulled the plug for IAC motor...no real change, maybe that's dead. While that may explain a bad idle, would that kind of failure affect performance in boost?
 
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Checked idle valve as per Bentley guide, and confirmed it is functioning.

Reset everything by way of disconnecting battery leads, and connecting wire terminals, to clear capacitors.

Car is hesitant to fire, and I have to work the throttle to get it to go. After that, it seems okay. Drove it a bit further, and still misses in boost. I'm GUESSING there is a fuel pressure related issue, and I did intermittently hear a seemingly angry main pump. I should have a gauge test kit here today.
 
Loose plug wire or plug "tip" (screws onto plug/where the wire connects)?

Good cap, rotor, wires and plugs?

Cylinder drop test at idle may identify an offending cylinder. Unplug on injector at a time.
 
ZVOLV said:
Loose plug wire or plug "tip" (screws onto plug/where the wire connects)?

Good cap, rotor, wires and plugs?

Cylinder drop test at idle may identify an offending cylinder. Unplug on injector at a time.
Click to expand...

All ignition components new and quality...i'll double check everything again.

i'll also do the cylinder drop test
 
Air leaks cause stuble going into boost. IAC hoses, IC coupler hose, or poor turbo inlet hose; they get soggy at the bottom at the turbo and leak.

Maybe build a pressure tester. Spray around with brake cleaner and see if rpm changes, smoke test, etc
 
ZVOLV said:
Air leaks cause stuble going into boost. IAC hoses, IC coupler hose, or poor turbo inlet hose; they get soggy at the bottom at the turbo and leak.
Click to expand...
All hoses new...replaced everything with either Genuine Volvo vacuum hose or DO88 silicone. I'll triple check my boost clamps.

Confirmed all the ignition components are in order. Did cylinder drop test at injectors, all four firing.

Fuel pressure gauge is "out for delivery"
 
Okay, all clamps tight, no leaks I can find.

Seems fine if i drive like an NA car. Decent if i don't push it. Under load, it starts to buck around at 4k rpm.
 
HC is unburnt fuel. You three way cat cleans up the three pollutants: HC, CO, and NoX.

Losing power at 4K doesn't sound like a learning issue. LH2.4 adjusts idle mixture and speed. One you are in boost and throttle, the ECM leaves closed loop and ignores the O2 sensor.

Have you confirmed the MAF female terminals and the terminal crimps are corrosion free? Maybe drag test the terminals with the correct male probe (from and old MaF) to confirm proper terminal tension.
 
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