TBI and Denver emissions?

[REDONE]

I officially moved from Park County to JeffCo so I have to smog the Money Badger. I know there's a number of Denver area guys running TBI, obviously the internet has provided no definitive answers to my questions, just anecdotal advice.

What smog equipment are you Denver guys running with your TBI system? Does the stock AIR injection system mess with the O^2 sensor?

Did you guys have to provide any kind of documentation for the TBI at the test station?

Thanks in advance for any insights, I'm sure I'll have more questions as soon as these are answered.

[AwesomeJ10]

I have personally never smog tested a TBI.

I think that technically speaking, it should be taken to the referee station and get examined by them.

but realistically - slap TBI on it, install all the air system, but run the hoses to up behind the tranny where they won't see.

the TBI will pass on first time - so long as they 'think' it's a carb.

[AwesomeJ10]

oh and the very best thing you can do for Colorado emissions (in order to avoid being upset over a stupid reason) is to get a new gas cap. Install it the day of the test.

AMHIK

[FSJ Guy]

Ha ha!! X2 on the NEW gas cap!! They WILL test it and you will be SUPER MAD if everything else passes but the cap.WHY? Because you have to do EVERYTHING all over again!

I have passed the IM240 test many times with TBI. As long as your AIR pump is hooked up to a belt, spinning and all the hoses are hooked up to it, you're good to go. I set my diverter valve to dump the fresh air into the tube that runs to the catalytic converter. Since it's downstream of the O2 sensor, it will not affect the TBI. Since I had computer controlled timing, I just ran my distributor vac hose to a spot underneath the air cleaner.

I even got a fast pass one time. This was running the Edelbrock Performer intake (non EGR) and Performer cam.

Just make sure you have a legal cat if your vehicle originally had it. That is about the only device they REALLY will check. One time, on a different vehicle, they got under there and checked the TOP of the cat to make sure it wasn't hollowed out and re-welded.

[shimniok]

Air system has to be set up to not inject into exhaust manifolds when in closed loop or it will screw up the mixture.

The inspectors look for air pump and hardware, catalytic convertor and emissions canister.

One of our prior members had mpfi and took it to referee with diagram and write up of operation. That's the way you're supposed to do it.

Sent from my XT1096 using Tapatalk

[REDONE]

Thanks for all the answers guys. I looked for the better part of an hour last night and I couldn't find anything in CO for an "emissions referee" but for anyone that searches this in the future here's what I've learned so far:

1) Air injection needs to go to the cat, NOT the manifolds, regardless of what hardware is present
2) None of the emissions stations in CO are actually run by the state, the ones I thought were are run by Envirotest which is the only private company allowed by the state to test 1982 and newer vehicles.
3) The 18 "independent test and repair" emissions stations are a racket, they will fail you and try to milk as much of the $715 dollars in repairs you need to qualify for a waiver out of you as they can.

So, I found all that on the test stations while trying to find out where an emissions referee might be, but I'm not sure it's a separate thing from Envirotest. The closest thing I could find was on Envirotest "about" page saying they provide referee services to California and Alaska, but nothing for CO. http://aircarecolorado.com/about-envirotest/

So, it seems gas cap, catalytic converter and presence of a spinning AIR pump are the key to passing (past the actual emissions part of the emissions test). It'll be a while before it's all together and ready to test but once I do, I'll report back with any discoveries.

[AwesomeJ10]

I've had a couple of very technical conversations with the referee's. They know their chit for sure. If you choose to get inspected by them, you better have everything setup perfect (according their book).

I still think you can jerry rig it up to 'appear' to be right and pass emissions no problem...

[REDONE]

I've had a couple of very technical conversations with the referee's. They know their chit for sure. If you choose to get inspected by them, you better have everything setup perfect (according their book).

I still think you can jerry rig it up to 'appear' to be right and pass emissions no problem...

Who are these referees and how do I find them? I honestly couldn't find anything about them in CO in an hour of googling.

[AwesomeJ10]

Heck I can't find it either.

Call one of the envirotest locations and ask them. IIRC, there are two referee's: one in Fort Collins and one in Lakeword or littleton

[csuengr]

I've had a couple of very technical conversations with the referee's. They know their chit for sure. If you choose to get inspected by them, you better have everything setup perfect (according their book).

I still think you can jerry rig it up to 'appear' to be right and pass emissions no problem...

Who are these referees and how do I find them? I honestly couldn't find anything about them in CO in an hour of googling.

I know there is one in FoCo. Seen him twice. He is a stickler. (Though he did give a pass to my CJ with a LT1 even though it had a VSS error code, cause there was no VSS)

Just make your emissions equipment look hooked up (functioning EGR will help though) and run it through normally. If you go to a referee, everything will have to work.

[babywag]

Can't speak for CO, but my '90 w/ TBI was fairly easy to get through smog in CA.

No smog pump, air injection lines, and only a few vacuum lines left.
Charcoal canister, EGR, PCV, and 1 CTO.
Single exhaust.

Just handed tech Howell EO# printout.
Said it's same system.
They ran it through ringer for like an hour. It passed visual, and evap, but failed on dyno.
Replaced the CAT and whizzed right through on retest.

[Nikkormat]

Bringing in the Howell print out is what I plan to do for the 91.

I'm going to rig it up according to their vacuum diagram. Have the air pump inject into the cat only. And run a charcoal cannister from a TBI Chevy. It fits in the bracket and looks stock. I believe that the key to passing is looking like you have your chit together. If it looks like it could be oem, and passed the dyno, it should pass without raising an eyebrow.

A big part of looking professional is how you plug the manifolds. A short bolt and a copper washer shouldn't raise any eyebrows. Or a set of shorty headers that don't have holes in the first place.

[Nikkormat]

This might be kind of shady... But I've also thought of having a sticker made up in OE style with the Howell diagram on it. Might not work on a more common FSJ but I might get away with it on the 91.

Heck, I've thought of buying a Howell kit and reselling everything but the sticker.

[srobertsfsj]

When I had the TBI installed, I dont think they even new what it was, pretty much looks like a carb. They just checked I just had the pump, AIR, canister and cat. They do check for the cat. I don't think it matters anyway since TBI if a fuel delivery system and they are only check for emissions stuff. No different than swapping the carb to a non-stock carb. Nothing they can say about it.

[FSJ Guy]

When I had the TBI installed, I dont think they even new what it was, pretty much looks like a carb. They just checked I just had the pump, AIR, canister and cat. They do check for the cat. I don't think it matters anyway since TBI if a fuel delivery system and they are only check for emissions stuff. No different than swapping the carb to a non-stock carb. Nothing they can say about it.

X2. And it's pretty cool to get the "Fast Pass" on a 1980's era V8 4x4!

[Grand_Wag_85]

Slight hijack but does the air pumping into the exhaust actually induce a chemical change in the emissions or just fool the sniffer into thinking the exhaust is cleaner?

[FSJ Guy]

The extra oxygen allows "after burning" of unburned fuel and allows the cat to do its thing better.

[Grand_Wag_85]

Gotcha

[Charles Kline]

Not sure if you've done your emissions test already but if you're talking the 79 you should have no problems since they just do the probe in the tail pipe at idle (no dymo)

I've seen them look for the Cat but never check anything else as far as Air pump or vac hose routing...

Mellow Yellow (also a 79) passed on its first try and it was running rich rich.

-Charles