Opinions on cutting out catalytic converters.

[mikeoverland]

Thanks for the reply. I knod of figured that it was "missing" a cat considering that every vacuume hose related to the remaining emissions and EGR are missing! They have been gone long enough for a mud dobber to build a home in the vacuum port on the EGR.....

 

[AuroraGirl]

81 as far as I know would have come with a cat, even Federal Emissions.

Goldie is an 80 and came with one.

i think the CAT or no CAT would all be GVW and engine/what gm decided to make it conform to. because you could buy a vehicle without cats up till 2004 although it was very very rare and mostly fords only did that. gm complied with most of the emission deadlines rather quickly

 

[Ellie Niner]

i think the CAT or no CAT would all be GVW and engine/what gm decided to make it conform to. because you could buy a vehicle without cats up till 2004 although it was very very rare and mostly fords only did that. gm complied with most of the emission deadlines rather quickly

I have a 1995 Airstream motorhome on a Ford chassis that has no catalyst. I'm pretty sure that had to be the absolute last year any gasoline fueled vehicle came without in the US, as they switched to OBD2 for 1996.

 

[DoubleDingo]

81 as far as I know would have come with a cat, even Federal Emissions.

Goldie is an 80 and came with one.

Especially being a C10

 

[AuroraGirl]

I have a 1995 Airstream motorhome on a Ford chassis that has no catalyst. I'm pretty sure that had to be the absolute last year any gasoline fueled vehicle came without in the US, as they switched to OBD2 for 1996.

1999 was the "leeway" phase in but to my knowledge gm was obd2 compliant in 1995 for most things and 1996 for all vehicles. 2004 was the leeway for heavy-duty light-duty trucks, so over 8600 but under 10,500 or whatever. some fords used that time. 2005 then all gasoline vehicles in light duty definition have obd2 period except maybe a very small contingent of low-numbers productions that got exemptions just like for safety(carrol shelby vehicles for example)

no idea about diesels but gas for sure

1994/1995 gm really made obd2 compliance in a LOT of their fleet impressively quickly. But not all of them, and not 100%. its kinda tricky. but 1996 gm was really good about all that

 

[Ellie Niner]

1999 was the "leeway" phase in but to my knowledge gm was obd2 compliant in 1995 for most things and 1996 for all vehicles. 2004 was the leeway for heavy-duty light-duty trucks, so over 8600 but under 10,500 or whatever. some fords used that time. 2005 then all gasoline vehicles in light duty definition have obd2 period except maybe a very small contingent of low-numbers productions that got exemptions just like for safety(carrol shelby vehicles for example)

no idea about diesels but gas for sure

1994/1995 gm really made obd2 compliance in a LOT of their fleet impressively quickly. But not all of them, and not 100%. its kinda tricky. but 1996 gm was really good about all that

Didn't know they went that late... living and learning.

And yep. My 1995 Firechicken had "OBD1.5", with the OBD2 connector already in place, and some functions already updated to the new standard.

 

[SirRobyn0]

@AyWoSch Motors You already have all kind of opinions, and you'll continue to get more. So here are some facts for you.

Catalytic converter pros:
Cleans up your exhaust, means less smell and better for the environment.
Exhaust has a gas in it called NOx NOx dissipates quickly and is not a long term environmental hazard, however it is really good at destroying lung tissue. If your sitting in traffic or working on your truck and your smelling your exhaust you can bet your breathing that in. Ask an mechanic with COPD how he got it. probably from that and / or smoking.
Your exhaust system will last longer with a cat because there will be less acidic deposits in the muffler and pipes.
Modern catalytic converters create such little back pressure that it cannot be detected on a backpressure test.
Acts somewhat like a resonator and will mellow the tone of the exhaust somewhat.


Catalytic converter cons:
Depending on converter installed it may create a small amount of restriction
Cost money to install

So for the above reasons I have a catalytic converter on my square and also on my 77 Cadillac.

 

[SirRobyn0]

1999 was the "leeway" phase in but to my knowledge gm was obd2 compliant in 1995 for most things and 1996 for all vehicles. 2004 was the leeway for heavy-duty light-duty trucks, so over 8600 but under 10,500 or whatever. some fords used that time. 2005 then all gasoline vehicles in light duty definition have obd2 period except maybe a very small contingent of low-numbers productions that got exemptions just like for safety(carrol shelby vehicles for example)

no idea about diesels but gas for sure

1994/1995 gm really made obd2 compliance in a LOT of their fleet impressively quickly. But not all of them, and not 100%. its kinda tricky. but 1996 gm was really good about all that

Didn't know they went that late... living and learning.

And yep. My 1995 Firechicken had "OBD1.5", with the OBD2 connector already in place, and some functions already updated to the new standard.

I don't know about the exact dates I think 99 is a bit late. I think that by 1996 or 97 light and heavy had to be OBD2, I know Ford pushed right to the end with their crappy original diagnostic system. And as said I remember what you guys are calling OBD 1.5 The thing that sucked about the OBD1.5 back in the day is some diagnostic tools did not know how to read those systems well at all. With the original OBD1 systems, GM diagnostics was light years ahead of all the other manufactures. Ford it was like pulling teeth to get info from their systems, GM it was easy, I honestly think OBD2 was built on the GM system and may explain why they adapted so quickly. GM was also the first manufacture to have a fuel injected system with built in diagnostics and data stream. That would be 1979 BTW in a Cadillac MPF.

 

[Ellie Niner]

I don't know about the exact dates I think 99 is a bit late. I think that by 1996 or 97 light and heavy had to be OBD2, I know Ford pushed right to the end with their crappy original diagnostic system. And as said I remember what you guys are calling OBD 1.5 The thing that sucked about the OBD1.5 back in the day is some diagnostic tools did not know how to read those systems well at all. With the original OBD1 systems, GM diagnostics was light years ahead of all the other manufactures. Ford it was like pulling teeth to get info from their systems, GM it was easy, I honestly think OBD2 was built on the GM system and may explain why they adapted so quickly. GM was also the first manufacture to have a fuel injected system with built in diagnostics and data stream. That would be 1979 BTW in a Cadillac MPF.

Yes. I'm rather fond of the GM OBD1 system... being able to retrieve fault codes and oxygen sensor activity with a paperclip in a pinch, absolutely rocks. And not so much (or at all) on Ford's EEC's. Eek.

 

[AuroraGirl]

I don't know about the exact dates I think 99 is a bit late. I think that by 1996 or 97 light and heavy had to be OBD2, I know Ford pushed right to the end with their crappy original diagnostic system. And as said I remember what you guys are calling OBD 1.5 The thing that sucked about the OBD1.5 back in the day is some diagnostic tools did not know how to read those systems well at all. With the original OBD1 systems, GM diagnostics was light years ahead of all the other manufactures. Ford it was like pulling teeth to get info from their systems, GM it was easy, I honestly think OBD2 was built on the GM system and may explain why they adapted so quickly. GM was also the first manufacture to have a fuel injected system with built in diagnostics and data stream. That would be 1979 BTW in a Cadillac MPF.

Yes. Im pretty sure the majority of the standards were based around how GM was heading with things and I think the reason is simply how large GM is/was. Like, they had the objectively most straight forward and helpful OBD1 setup and even tho they had a lot of different systems they used the same connector - period - (minus some odd balls they owned or had owner share in overseas like daewoo, saab, etc) and that made a lot of sense to the way things were headed. A big part of OBD2 stuff was a standardization of codes and meanings, a defined system of technical service bulletins(Which gm had techline and Cams terminals which were providing this information digitally and the regular dealer materials as well, they had tech support lines to help go through diagnostics(part of OBD2 would be that manufactures need to provide a means to access factory service information so independent repair could work on these more complex cars and do so for years to come, so service data became more precise), of course a standard connector which would be placed in a spot readily accessible from either crouched down on the driver or passenger side(for most part, looking at you FORD), and of course, ultimately, a universal goal of no matter what vehicle or make, the system is in place to monitor and keep in good health the catalyst on the vehicle and keep it operating for years to come. OBD1 vehicles notably often had 1 oxygen sensor for AFR but obd2 would mean there would be a way to measure before and after for catalyst monitoring and also this enabled complex air-less three way cat converters because the post-cat sensor could be utilized to purposefully adjust the AFR to richen and lean the mixture periodically to provide what an AIR pump and setup would but to do so automatically and with less complexity. some vehicles obviously didnt get so lucky as others on this but GM shaped a lot of these things.

Also when it comes to ASE and "how to be a technician" GM made the "strategy based diagnostics" which is now a big part of tech school

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but I should rephrase from my previous comment. 1999 was the last year for light-duty vehicles under 8600 gvw to be fully compliant with OBD2. OBD2 connector for most part and most Readiness indicators (IM Monitors) and VIN reading, flashable PROM(EEPROM) as to make PCMs have to be flashed instead of chips or updates to the PCM itself physically, the VIN be readable with a tool, the obd2 port use a ISO defined standard(Thats where the obd1.5 had a lot of trouble, the port was right but the standards werent the OBD2 "standards" that most scan tools have in their programming)
Then 2004 was the last year for heavy-duty light-duty vehicles to be fully compliant with OBD2.

1994-1995 was a mess
1996 most automakers just done, down, got it here full stop. THen there is Ford (EEC-IV for most part)
I cant think of another example where an automaker DIDNT have obd2 compliance by 1996 but I know euro cars or at least VW audi have "vagcom" or something dumb that I dont care to learn about.

There is also the fact that California frequently and seemingly always has a one-up on the standards of everything else literally everywhere, so you may be held to a higher standard in, say, 1996 than federal emissions cars, but thats California.

The 1996 obd2 and 1999 full compliance leeway was to not be overburdening on things like Ford because theyhad ahard time with things. But sinceOBD2 was a lot of things at once, I think its safe to say most car makes had the connector, had the standard communication protocal, used standard codes, used a post cat o2, had IM monitors at least in part, had misfire monitoring, had PCMs that could be flashed instead of PROM chips, and block-integer learningfor AFR corrections. all the small potatoes were far and few between thankfully. For ford,there 1997"heavy duty" f250, their super dutys being a very highGVW, their engine choices being petrol hounds(v10, 460, etc) and the like were because 8600gvw and higher could be looser regs and also things over 10,000 gvw werent required to use a standard protocal because "medium duty" and they could have a proprietary(eec-iv) computer system for a while longer. they really held on for dearlife tho...

 

[AuroraGirl]

Yes. I'm rather fond of the GM OBD1 system... being able to retrieve fault codes and oxygen sensor activity with a paperclip in a pinch, absolutely rocks. And not so much (or at all) on Ford's EEC's. Eek.

I mean Unless trucks are different the rate of flashing on the CEL if you put it in Field Service Mode, and blinking two and one half times per second tells you it's in Open Loop, and if it's blinking once per second, it's in Closed loop. I guess thats oxygen sensor feedback in a way. crude but directly correlated. I wish when reading the OBD1 codes the Electric Fan on gm cars with electric fans didnt go to full speed during it. Its annoying. helpful. annoying.

 

[Bextreme04]

81 as far as I know would have come with a cat, even Federal Emissions.

Goldie is an 80 and came with one.

My 1980 K25 did not come with cats.. it is the 8600GVW option though.

http://www.73-87.com/7387info/7387emislevel.htm

 

[Ellie Niner]

I mean Unless trucks are different the rate of flashing on the CEL if you put it in Field Service Mode, and blinking two and one half times per second tells you it's in Open Loop, and if it's blinking once per second, it's in Closed loop. I guess thats oxygen sensor feedback in a way. crude but directly correlated. I wish when reading the OBD1 codes the Electric Fan on gm cars with electric fans didnt go to full speed during it. Its annoying. helpful. annoying.

If you stick your paper clip in (geez. that didn't sound right) after the engine is running, it will flash the CEL to indicate the state of the O2 sensor. I think on is rich and off is lean. It can cycle faster than 2.5 times per second. Wasn't aware of a way to get it to tell you whether you're in open or closed loop. How's that done?

 

[AuroraGirl]

If you stick your paper clip in (geez. that didn't sound right) after the engine is running, it will flash the CEL to indicate the state of the O2 sensor. I think on is rich and off is lean. It can cycle faster than 2.5 times per second. Wasn't aware of a way to get it to tell you whether you're in open or closed loop. How's that done?

the same way you just described. the state of the o2 sensor is essentially the closed, open loop thing. If you punch the throttle you will see it go "open" and if you cruise it will go closed but if you are not warmed up yet you will always be open, if you test it out that way.

myy 1990 olds is cool when you put it in field test mode the computer on the dash says "FIELD TEST MODE"

 

[AuroraGirl]

My 1980 K25 did not come with cats.. it is the 8600GVW option though.

http://www.73-87.com/7387info/7387emislevel.htm

me too