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Discussion Starter #1
Just checked for codes on my 90' Bronco today, after the Christmas fun ofcourse, and she kicked out a 311 code during the running portion of the test.

In my OBD I code reader manual this is listed as "Thermactor air system/fault during engine run self-test."

I need to go through emissions soon which is why I was checking for codes.

I recently just put the air pump pulley and associated longer belt back on, and she passed fine a couple of years ago (last time through).

However, the changes since going through last time are huge. As in completely different engine.

To make it short and get to the main difference as far as emissions might be concerned, well.............my Topline heads don't have the Thermactor air passages drilled to allow the air to be injected into the exhaust ports. I still have the tubes bolted up that go across the back head to head, and she still has the air tube going to my two high flow cats (so visually she looks good).

So, I'm not sure that the lack of the Thermactor ports in my heads is the actuall reason for kicking out the 311 code, but I must assume so at this point since thats the only change that should be affecting the Thermactor system.

I have to go through AZ emissions testing. Pretty sure its for the most part as tough as CA with few exceptions. It is idle, and load tested. Load tested at several different speeds if I remember right.

I think it will pass the sniffer part.





My concern is, if they see that code does that fail it right there all by itself regardless of how clean it actually might be running?????
 

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Ex Navy Nuke
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5,423 Posts
If your heads don't have the holes for the thermactor air to be injected then what makes you think it will pass a sniffer test? Not sure but I doubt the lack of the holes in the heads will give that code. It's probably the TAD or TAB solenoid(s) that are bad or a vacuum line. As far as if they will fail you for having a code; I don't know.
 

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Zombie Hunter
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Not sure how it works in AZ, as long as your not thowing a visual check engine code, (the check engine light is on) they will test it.

Ohio is a bit weird though. They just sniff, they don't hook anything up.
 

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Discussion Starter #4
I was hopeing since many engines pre air pump will pass emissions without issue that this engine with its mild cam would have no issue as far as emissions output. On the no air injection ports in the heads, well.........I guess I was just hopeing all the air would just be diverted to the cats since that is still opened up.

It is not making the check engine light come on, and I know the bulb is good and the light works because I started it recently with the IAT (intake air temp) sensor unplugged, and the CEL came right on and stayed on.

Runs real clean and very tame compared to some hotrods I've gotten through emissions before.

I think the testing here is very close to Cali, with the exception of them not bothering if you have emissions legal headers, or whether you have cats or not.

They plug right in to the under the hood diagnostics plug, then start testing. Idle, then appears to be load on the rollers at sustained various rpms.

I'm relatively confident that she's running clean enough. My main concern as I sit here is if they see that code will that fail it regardless of how clean it is running.

If only I had a Tweecer, I could turn the Thermactor system off since I'm running the Lightning EEC.

Wondering if there is a cheapy little trick like the trick you can do on the EGR to make the EEC think its operating fine. Like some kind of little resistor trick.

Guess I might have to make some calls this week, or just go through and see wtf happens.
 

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OUT OF BUSINESS / M.I.A.
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no cheap way to clear that code. the O2 sensor is looking for extra air from the air pumped into the back of the heads.

Everything has to be working for that code to go away
OR TwEECer the computer and hope they don't look for a chip.
 

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Diesel Gynachologist
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you can get it to pass and if you pass the visial, meaning your going to have to have the smog pump and bs on there cause they are going to look for it. Even if its not really doing anything they are going to want to see it. Now the tricky part is getting it clean enough to pass, the only way your going to know is run it through.

they wont pull codes on your truck just run it on the rollers and test HC NOX and CO
 

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Discussion Starter #7
Thanks guys.

They do plug into the diagnostic plug under the hood if I remember correctly. So, if they aren't checking for codes, then wtf are they doing plugging in? Thats the part that has me worried.

She will absolutely pass the visual as it is all there and hooked up. I even think it will very likely pass the sniffer as well.

Just a little concerned about them seeing the KOER 311 code. Again, no CEL on at all. Doesn't come on during running.

I did come across some info on the Corral stateing the air system functions in 3 ways. Not sure if this was accurate info. The info said, during warm up the air is diverted to the heads to help with complete burning, then once warmed up it is diverted to the cats, then finally under decel it is diverted out to avoid backfire. I think that was how it went.

Just going to run her through and see how she does, or if they say anything.
 

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Diesel Gynachologist
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as far as I know they dont pull goes on EEC IV. I dont remember then doing it to my 93. just running it on the rollers
 

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Discussion Starter #9
Well, not sure why I remembered them checking for codes as they didn't today.

Just got Betsy through emissions finally.

First test, and she passed.

Non emissions heads (no Thermactor ports), 112 LSA Comp Roller cam with a Lightning EEC and still Speed Density, with no tuner yet!

She didn't fly through, but she made it.

I made sure she was nice and warmed up with a little freeway action with the OD off right before. Not sure if it helped, this bitch runs real cool no matter what I do.

So, she didn't pass as easily as my original stock engine had on its last time being tested.

Todays numbers where:

HC's 2.07 on a 3.00 standard (limit) Pass

CO 12.46 on a 25.00 standard Pass

NOX 3.20 on a 5.00 standard Pass

Equipment test was:

Gas Cap (?)

Pressure Test (?)

EVAP Components (?)



Previous test numbers with strong stock engine a couple of years ago:

HC .51

CO 19.35

NOX 1.59



I'm fairly happy as I did have some concerns with my heads, the cam, the EEC, and no tuner yet. She seems to have a small miss or something to the idle, as well as in the low part throttle cruising area. Both of which I'm sure are tuning related. So, between those tune issues I'm aware of, and the Thermactor code, and problems I've had in the past with strong strip / street muscle cars .........well yah I was a little concerned. Had she not passed though I had a real bag of tricks I learned on the Corral that I was going to throw at it that I'm confident would have gotten it through no matter what (almost).

Just thought I'd give an update on this if nothing else but to show that you can have non-emissions high performance heads, a cam thats not suppose to be speed density friendly, a more aggresive timing tabled EEC and still get through, sometimes.
 
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