Hello Everyone!

I hope you guys can help me. My H2 check engine light is on and scanner giving code P0420 catalytic converter.
One of the cats giving errors and CO2 is too high - 0,30.
Does anyone know, if I replace my catalytic converter with universal one, is the CO2 then OK, or it have to be OEM cat?

Best regards from Estonia

 

If you don't use oem, that engine light will prob stay on. I remember someone else saying that on the forum in the past.

 

My CATs were so bad, like buckets of sand!


So I removed the two exhausts, cut-out the CAT boxes, welded in Universal Magnaflows and replaced the O2 Sensors (buy a good removal wrench and TAP)


I can't see how the ECU could differentiate replacement CAT's, mibe have been 100% (touch-wood!!!)


Welding was a bit tricky, I'm happy to elaborate if you need help.

 

Thank you for help and info, I appreciate that!
New CO2 are OEM or aftermarket? I also notices O2 simulators in ebay with good price.
I was thinking also replace cats with universals or maybe high flow cats. I'm going to add also LPG system next week, so driving with LPG the CO2 must be zero [img]images/smilies/smile.gif[/img]

Best regards from Estonia

 

Looked at ACDelco's but BOSCH got good reviews, so didn't go OEM, anyway the CATs weren't.



Note: The Upstream & Downstream sensor are different P/Nos (different cable lengths)


So from RockAutos I bought:-


1-off Lisle Dual Drive Oxygen Sensor Wrench P/No 12390 £10.45 $14.11

1-off Lisle Oxygen Sensor Thread Chaser P/No 12230 £2.45 $3.31

1-off BOSCH Oxygen Sensor P/No 15282 £32.42 $43.79

1-off BOSCH Oxygen Sensor P/No 15895 £25.01 $33.78



Some so tips:-


Removing the sensors was very, very tough as you can imagine. The Lisle tools were excellent and a "must have"


No grease is required for the O2 Sensors they come pre-prepared to avoid damaging the CAT'a !!!


LPG, sounds like you're in Europe, what country?


My truck runs on LPG, make sure you get a valve saver system fitted.


LPG roughly doubles the fuel economy if we can use that word for Hummers!

 

Also when you've fitted the CATs don't just start driving with them, make sure you break them in.





Hope you find this useful

 

Hello,

yes, Im form Europe, Estonia.
Last week I got installed LPG system.
Hope H2 had good "mileage" with LPG, will see that next week My last cars had really good mileage (GMC Savana, Chevy Express etc.)
On thuesday I will install Magnaflow catalytic converter, I hope I can get my CO2 samples in normal.
Is the Bank1 catalytic converter the driver side one?
Oceanbrave, whats your H2 avarage LPG mileage is on highway and in town?

Best r.
Karla

 

Yes I think bank one is the driver's side, however I would change both whilst you are doing the work, then the job is done.


Couple of things to mention:-

• Take loads of photos of your exhaust system before you start!
• The manifild nuts are really hard to undo, I actually destroyed one air-tool in the process, I was frightend of shearing the manifold bolts.
• Make sure you have the all the exhaust gaskets you need (can't remember how many, but RockAutos will list them for reference)
• Once you have cut-out the old cats you will be faced with the problem of alignment. I temporarily mounted everything back in the truck making sure it aligned and mounted with all the brackets, and didnt touch anything and "tack-welded" it together "in situ" Then I removed it again and weld-up properly making sure there were no blow holes. I had to fit small collars to connect the CATs to the pipes as there was not much free length to work with.
• Make sure the old Lambda Sensors have been removed, its easier to do before the system is re-fitted, re-tap the holes and make sure the new sensors will screw-in. This was harder than I imagined, I needed the special tool and the tap, lots of penetrating oil and brute force!!!

Re mileage, that's complicated because it depends on the relative price of LPG to petrol. For me I'd say it basically doubles the MPG so around 20-25 MPG.


Good luck with the CTAS