Community Forums

FIRE UP · 11-15-2020, 05:31 PM

Quote:

Originally Posted by ArtJoyce

Not sure test tubes work anylonger. They were great when the cats first came out. You would get improved performance.

Now with the ecm making engine adjustments realtime, based on feedback from o2 and air sensors, etc... It could cost you several mpg and 15 to 25% of your hp.

Heeyyyy,
Someone that actually knows and realizes what's going on in, under, around and over engines and total operations. Yep, you mess with one of todays engines and, the ECM will know it and send you the infamous *CEL* or, Check Engine Light!
Scott

R.Wold · 11-15-2020, 09:00 PM

not sure that’s the case for a 2002 F53

n2zon · 11-16-2020, 04:15 AM

Quote:

Originally Posted by R.Wold

not sure that’s the case for a 2002 F53

It likely depends on whether there is a post-cat O2 sensor.

ArtJoyce · 11-20-2020, 06:35 PM

I think by 2002 they had both up s MN d DC own stream o2. I know my 2001 toyota did. The real issue is if the o2 thinks it's to rich, it will lean it out. The leaner it is it runs hotter. Not saying it would happen, but to learn and you will burn out exhust valves.

ArtJoyce · 11-20-2020, 07:49 PM

Both up and down stream o2.

R.Wold · 11-20-2020, 08:36 PM

Quote:

Originally Posted by ArtJoyce

Both up and down stream o2.

and “ but to lean and you will burn out exhaust valves.“ Hard to keep up with preefrooding all this stuff...

n2zon · 11-21-2020, 05:37 AM

Quote:

Originally Posted by ArtJoyce

Both up and down stream o2.

In that case, the MIL/CEL/Check Engine Light will light if a "test pipe" is used, because the ECM will not see a functional catalytic converter.

n2zon · 11-21-2020, 05:47 AM

Quote:

Originally Posted by ArtJoyce

I think by 2002 they had both up s MN d DC own stream o2. I know my 2001 toyota did. The real issue is if the o2 thinks it's to rich, it will lean it out. The leaner it is it runs hotter. Not saying it would happen, but to learn and you will burn out exhust valves.

Only the upstream O2 sensor is used to adjust the mix. The downstream one is used only to determine whether the cat is working OK. Also, if the mixture gets too far off the map*, the ECM will light the Check Engine light.

* Every engine and operating environment is a bit different. To make engines more responsive, the ECM stores injector pulse width values (which affect the mixture) and others (such as spark timing) for a number of combinations of airflow and temperature. When conditions change quickly, the ECM uses the stored, mapped value and then fine-tunes it using the upstream O2 sensor when it's in "closed loop" operation. The values are adjusted as you drive, and the derived values overwrite the old ones when they differ by some amount. This is why it takes engines a little driving time to run perfectly again after a hard ECM reset; the default values need to get overwritten with those appropriate for the operating environment. Also, there are "plausability checks" built into the ECM programming. If the inputs the ECM sees are not plausible, you again get a CEL. This is all from memory, so take details with a grain of salt.

JPeterson · 11-21-2020, 05:50 AM

My 2006 V10 does not have a sensor after the cat - only before. Many years ago the catalytic converter was "gutted" and reinstalled by a mechanic that told me it was the cause of the engines' poor performance. It did not noticeably improve performance but did make it noticeably louder.

345 desoto · 11-21-2020, 06:04 AM

Would my 1988 Winnebago 454 have an O2 sensor?...

David 70 · 11-21-2020, 10:50 AM

If it has a throttle body I would think it would. I know 1988 was the first year Chevy went carburetor to throttle body on their pickups. I can't say for sure on the heavier duties. The chassis could also be a year earlier.

daniel71 · 02-01-2021, 02:57 PM

My catalytic converter was stolen from my Ford Class A 2018 Winnebago Vista that was stored in a locked /gated storage area but the criminals still stole it. Getting a new one now but looking for ideas to prevent this for happening again Any suggestions I can use to deter these criminals.

Mel556180 · 02-01-2021, 04:55 PM

Armed guards?
Not to minimize your plight, but determined thieves can get just about anything they really want.
Best you can do is make it unattractive to try.

awol50 · 02-04-2021, 10:00 PM

Build a square 4 sided box out of 2x lumber with inside steel 90s and screwed together at the corners. Say 6ft square. Mark on the floor where your cat is. Back the rv up. Pull the box in place and put 4-6 100# bags of sand around inside at corners and sides.
Make as tall as you can, just as long as it dont touch as you move rv in/out. Might work unless you have clearance problems preventing you from making the box tall enough. $100 or less total.