Colorado emissions without a cat

[sashephe]

Hello Diesel Page Forums,

I'm the recent owner of a 1995 suburban 2500 powered by the 6.5l diesel. So far the truck has been perfect, with no starting, running, or overheating problems, but now I am running into a problem presented by emissions testing in Colorado (specifically Aurora).

There are apparently two factors which determine a pass/fail on the emissions test. First is opacity, which I am unsure whether or not I will pass as I have not done the test yet. Second is the visual test, which I will not pass. The previous owner of the suburban cut out the cat and welded in a straight pipe.

I'm wondering what the best solution in this situation is. I've seen some hollow cats on some ricer website (off-road use only, of course), but outside of that, I imagine I would have to buy an actual cat, which I would prefer not to have on the truck (nor do I want to pay more for it). I wouldn't mind paying for a new 3.5" or 4" exhaust, but I don't really see any that come with cats. I also do not have any welding equipment, so anything that takes more than a wrench and some time will have to be done at a shop.

I guess what it comes down to is that I would like to be able to pass CO emissions without having to shell out a ton of money (unless it's for a new, larger, exhaust), and I would prefer not to have a cat on the truck.

What do you all think?

As I side not, where is the factory location for the cat? Just in case I have to get something welded in.

[phantom309]

To determine if your truck came with a cat,. look at the vin # if it has an F,. then it never had a cat,.S engines had egr setup and cat,.
I'd be surprised if it is an S engine in a 2500 burb,..

nick

[sashephe]

That would be awesome, and make my life a whole lot easier. I just check the vin number and there is an F, although there are also a couple of Ss.

The number is 1GNGK26F8SJ394397

Am I free to spend my more interesting things?

[94 at Large]

According to GM the eighth character in the vin is the engine code. "F"

[sashephe]

So does this apply to the "soot trap" that is occasionally reference when speaking about these engines, or does having an "F" code engine only excuse me from having a traditional "cat".

My apologies if this seems redundant, I just want to be sure before I go spend $40 at the emissions place.

[phantom309]

So does this apply to the "soot trap" that is occasionally reference when speaking about these engines, or does having an "F" code engine only excuse me from having a traditional "cat".

My apologies if this seems redundant, I just want to be sure before I go spend $40 at the emissions place.

An F code truck does not have a cat,. or soot trap as some folks call it,.
you are good to go,..

nick

[john8662]

Any 1994+ 6.5 has a CAT installed from factory. So the 1995 Suburban for sure did and is supposed to be equipped with one.

There is a sticker in the engine bay that will say Catalyst.

The only 6.5's that didn't have a CAT are the 92-93 years only.

[DmaxMaverick]

Any 1994+ 6.5 has a CAT installed from factory. So the 1995 Suburban for sure did and is supposed to be equipped with one.

There is a sticker in the engine bay that will say Catalyst.

The only 6.5's that didn't have a CAT are the 92-93 years only.

This.

I don't know of any 94+, of any US emission standard that doesn't, or didn't, have a cat. I don't think Canada is/was different, but I can't confirm that.

If it "looks" like the cat was cut out and replaced with a straight pipe, that's what happened.

"CAT" and "soot trap" are one in the same. They are all catalytic converters, but on early Diesels with them, they commonly plug up with soot early in life (compared to gassers), hence the nick-name. They will also not affect opacity testing. If the cat is plugged, it just allows for less flow, and results in poor running. A failed opacity test will usually lead back to timing or the condition of injectors (absent aftermarket programming, which changes the conditions). A taller TDCO will usually clean it up in most cases, but you can't fix bad injectors with programming.

The "F" and "S" engines (8th digit of the VIN) determines the presence of EGR, and little else of any consequence. "S" engines have EGR, "F" engines don't. It's that simple.

[phantom309]

Any 1994+ 6.5 has a CAT installed from factory. So the 1995 Suburban for sure did and is supposed to be equipped with one.

There is a sticker in the engine bay that will say Catalyst.

The only 6.5's that didn't have a CAT are the 92-93 years only.

How interesting,.. i looked all over under the hood tonight,. could not find such a sticker,.My truck gets emissions tested every 2 yrs,.. never has been challenged,.?? I thought it had to do with gvw rating,..??. I known a guy in my area, his truck is a 2500,. but it has 6 bolt wheels and is rated lighter (7200lbs) than mine with the 8 bolt wheels and an 8600lb gvw.
sorry if i mislead anyone.
Mine is a cdn truck.

UPDATE:: i wikipeda searched and got this ,.....http://en.wikipedia.org/wiki/Detroit_Diesel_V8_engine


There are several GM 6.5 liter diesel engine production options. The Turbocharged L56, (VIN "S") was used in most light duty 3/4 ton (2500) Heavy duty 3/4 ton and 1 ton trucks used the Turbocharged L65 (VIN "F") engine. The L56 is emissions controlled with EGR (http://en.wikipedia.org/wiki/Exhaust_gas_recirculation) and catalytic converters. The L65 engine has no EGR, and has no catalytic converter (http://en.wikipedia.org/wiki/Catalytic_converter). There is a soot trap on L65 engines that is often mistaken for a catalytic converter.