Could Black Bear Tune = failed emissions test??

[TheFuzz]

I just smogged my Tahoe here in CA with a 91 BlackBear tune...passed just fine. Well within limits. I'd say cats could be heading south, too high comb temp (clogged fuel filter?), maybe seafoam it...

Thanks Physh. Good to hear. I didn't want to believe that the tune had anything to do with it, but only 2 things changed from last year's test to this year's test, 1) the tune and 2) Colorado started testing for NOX in the emissions. It is possible that the truck has been putting out high NOX scores for years and years and I never would have known since they weren't looking for it.

Damn man, sorry to hear this. Wish I could help out. Hope you get it resolved quick

Thanks bro. This is kind of a nightmare, but hopefully I'll get it ironed out this weekend.

For now I'm focusing on the EGR valve (if my truck has one) and the MAF sensor. I've read other posts about people looking for the EGR valve and discovering that their Tahoe/Yukon doesn't have one, so thats a little disconcerting...but I'm pretty sure that it's just the flex-fuel trucks that don't have an EGR system. Mine is a regular gasser. Hopefully I'll get lucky and find the valve, clean the snot out of it and it will pass. Plugged or non-functioning EGR valves are the most common culprit of high NOX scores from what I've been reading.

Should have done more research yesterday before coming on here and worrying everyone about their tunes, but I was a little panicked at the prospect of having to buy the truck back! I still am, but at least I have a couple of other things to focus on now.

 

[Rivieraracing]

Didn't you say that the guy was running 85 grade fuel but the tune is for the super unleaded? How long ago did he stop running that fuel or is he still using it?

 

[TheFuzz]

He said he only put about $10 worth of 85 into it, then promptly filled it full of 91 octane once the CEL came on. I told him to drive the sh*t out of the truck and fill it up with 91 again just to ensure that there was no remaining 85 octane in it.

A couple of local tech's I've talked to said that the low octane issue in and of itself probably couldn't raise the NOX score by too much. I'm hoping it's the EGR valve. Cleaning it would be a very easy fix, and even if I have to replace it it's still a helluva lot cheaper than buying new cats.

 

[Rivieraracing]

The hard part is that you are taking his word for it, and the problem is that it won't pass the test and he might be downplaying it!! So how long ago did he say he did it and how many full tanks ago?

 

[Tahoewhat]

i really have no help in this issue, but why do you have to fix it or buy it back? I guess diff. states maybe? b/c when i sold a couple cars ive had, sold them as is, and had them sign paperwork and all. They cant come to me for anything.

But im with chris, riviera, $10 bucks of gas, thats not even going to move the needle in our trucks. To me if he ran the wrong octane and the light came on, all that might have something to do w/ it. For some reason i just doubt he put 10bucks in.

but idk, hope you get it figured out.

 

[TheFuzz]

Well see I grew up in Ohio...you sell a car, you sell it as is. No emissions BS to deal with in Ohio. Emissions laws in CO are different. I've never sold a car here before so I really didn't know - I had him sign a bill of sale complete with the "no warranty is expressed or implied by the seller" clause, but apparently emissions is a whole different ball game. If you sell a car and it won't pass, it's your ass. You have to fix it, and if it can't be fixed, you have to buy the car back.

When it comes right down to it, this is his fault in my mind. The truck was fine when he took possession of it. He put the wrong fuel in it, he caused the CEL. I will be getting more opinions on this, but it didn't fail the test by very much at all, and only failed in one area. If there was pre-ignition detonation going on during the test, even if it wasn't enough to throw another code, that could have caused the failure.

I'm hoping it doesn't go very far and I can just clean the EGR valve and be done with this whole mess. If ends up in court, I think I have a decent case.

 

[Tahoewhat]

Well see I grew up in Ohio...you sell a car, you sell it as is. No emissions BS to deal with in Ohio. Emissions laws in CO are different. I've never sold a car here before so I really didn't know - I had him sign a bill of sale complete with the "no warranty is expressed or implied by the seller" clause, but apparently emissions is a whole different ball game. If you sell a car and it won't pass, it's your ass. You have to fix it, and if it can't be fixed, you have to buy the car back.

Very interesting. I guess it makes sense for emissions, but not really as in making someone buy the car back. hum.. interesting though.. Learn something new everyday..

Hope you get it figured out.

 

[TheFuzz]

Yeah, this is a news flash for me too. Most commonly the seller will just fix the emissions problem. I think an actual buyback is the worse case scenario - that will only happen if the problem CANT be fixed and the buyer can't legally drive the car.

 

[TheFuzz]

Well, cleaned the MAF and EGR valve today. The EGR valve was obviously the OEM one installed 10 years ago at the factory...the gasket was toast. It wasn't leaking I dont think, but it was destroyed when I pulled the valve off. Not a big deal, a new Fel-Pro EGR valve gasket was $.99, lol.

I didn't really know what to look for when checking it out, but I did notice that the diaphragm inside was moving freely once I sprayed some electronics-safe cleaner into it. I presume that is a good thing, as the diaphragm may have been sticking a little before hand. There was a good layer of carbon built up, but nothing was clogged as far as I could see.

Cleaned the MAF sensor too, just for the hell of it. It's going back for an emissions retest on Monday, so hopefully I will have some good news then.

 

[Tahoewhat]

i dont know, but shouldnt the emissions place be able to tell you why it didnt pass. I know maybe not exactly, but at least close to what the problem is.

Not in a mean way, just curious. Would make things make easier. lol