Failed TX emissions - 31K mile TTA

[Jerryl]

Trying to assist a local friend . . .
The car failed twice and not sure what to do next. (See attached pic for test results)
Last year, with the same setup, the car passed.
Other than chip and FP, nothing was changed.The car get driven about 1000 miles/year.

We installed the TT emissions chip, lowered FP to 37, got it up to +190F on a stretch of highway and dove it to the test station.
Car runs on straight 93.

The car is a +95% stock 89 TTA, 31K miles.
Here are the mods;
-AFPR
-Blue top injectors with matching TT Emissions chip
-Upgraded fuel pump.
-Valve cover breathers (2)
-Plug wires
(I think that is about it)

Here is a list of maintenance related items, that I am aware of;
-Car runs fine, and O2 sensor appears to be a a purple wire Delco.
-Plugs and wires appear to be ok (???) Car runs fine, no issues.
-TPS / IAC / LV / CC / all look good.
-Idle BLM is around 136 (idle cell), but once on the gas, the next BLM cell is right around 128.
-CAT is new original replacement with less than 3K miles
-The only thing I did not like was the MAF reading of 4@775 rpm (Park).

I will perform the EGR test tomorrow.
Any feedback is appreciated.

 

[turbojd]

If the cat converter is new, I would make sure that the egr is functioning properly. Check the diaphram for leaks, make sure egr goes in and out on the needle shaft. I take mine out and check for carbon build up and clean it up before i go to emissions.

 

[it's just a six]

I always have the test guy run the engine to 2500 for 5 minutes to "light off the cat"
Then adding denatured alky to the fuel tank always helps.
Also,retarding the timing does wonders for passing.
Goodluck

 

[CST 03]

I guess you guys in Texas don't have an emissions exempt. We here in PA. have it. If you drive your car less then 5,000 miles a year you don't have to get emissions. I get an emissions exempt sticker on my Cobra and GN.

 

[Jerryl]

Thanks guys.
I will look into the EGR when it stops raining.

 

[charlief1]

I always have the test guy run the engine to 2500 for 5 minutes to "light off the cat"
Then adding denatured alky to the fuel tank always helps.
Also,retarding the timing does wonders for passing.
Goodluck

The alky will help but if you add about 30% E-85 it will do the same thing and clean things up overall Jerryl. The timing does need to be cut back a little to cut the NOX down. Make sure the car is run on the freeway for about 20 minutes to get it hot as well. Tell us if the EGR is giving him an issue as well. These three things will help it pass for sure.

 

[pmoore4321]

Bummer, I see you are talking about a 1989 Trans Am. I was going to tell you your car would be emissions exempt after this year. My 87 GN won't pass either, but I am just going to wing it until the end of the year. Vehicles 24 years and older are emissions exempt in Texas for those who did not know.

 

[Jerryl]

The alky will help but if you add about 30% E-85 it will do the same thing and clean things up overall Jerryl. The timing does need to be cut back a little to cut the NOX down. Make sure the car is run on the freeway for about 20 minutes to get it hot as well. Tell us if the EGR is giving him an issue as well. These three things will help it pass for sure.

Charlie,
Idle/cruise timing can not be adjusted in a TT chip.
Have not tried adjusting it in the emissions chip, so, I need to verify to be 100% sure.
If she does not pass after the EGR diagnostics, E85 it is, after I burn off some gas in the tank.
Thanks for the feedback!

 

[salvageV6]

You failed HC too, I'd check the plugs as in pull most if not all of them for sure, fuel pressure double check, and of course the EGR may be stuck shut or have no vacuum etc.

Has the car ever passed with the newer cat.?

 

[Jerryl]

You failed HC too, I'd check the plugs as in pull most if not all of them for sure, fuel pressure double check, and of course the EGR may be stuck shut or have no vacuum etc.

Has the car ever passed with the newer cat.?

Actually, it did last year, with the new cat.
Thanks for the advice.

 

[dvernst]

You can do what I did. I failed two times, so I turned the fuel pressure down much lower than the computer can compensate for. It was under 20 psi. I turned it back up right outside the emissions place. I also disconnected the waste gate actuator so the car wouldn't get any boost. It passed right away doing this. They didn't even have to complete the whole dyno test. HTH. Dave

 

[Jerryl]

You can do what I did. I failed two times, so I turned the fuel pressure down much lower than the computer can compensate for. It was under 20 psi. I turned it back up right outside the emissions place. I also disconnected the waste gate actuator so the car wouldn't get any boost. It passed right away doing this. They didn't even have to complete the whole dyno test. HTH. Dave

Thanks Dave!

I always thought that a mixture that is too lean could result in a misfire, and increase HC . . . . . the same lean mixture could also increase Nox.

 

[Sal 87WE2]

Bummer, I see you are talking about a 1989 Trans Am. I was going to tell you your car would be emissions exempt after this year. My 87 GN won't pass either, but I am just going to wing it until the end of the year. Vehicles 24 years and older are emissions exempt in Texas for those who did not know.

Hmm, didnt know that. Does that mean we can drive cat-less too?

What about window tint, the guy that was going to inspect mine said he doesnt check for window tint on older vehicles like mine...
I know 25% or lighter is legal but i have 20%

 

[JDEstill]

I came to this section to pose a similar question, but since my questions are so close to the original poster's (hey Jerryl!) I'll just tack them on to this thread.

I failed my emissions 2 weeks ago with my regular TT chip, high NOx was the problem. Went back last week with my emissions chip installed and failed again, though it got a lot better. I'm sure this was because of the EGR being re-enabled. This time it only failed one portion of the test, the 25 mph portion. Here's my results, plus those from the last time it passed a couple of years back:

15 mph tests

HC (ppm)
9/28/07 - 113
3/6/10 - 38
3/13/10 - 40
Limit - 152

CO (%)
9/28/07 - 0.85
3/6/10 - 0.02
3/13/10 - 0.00
Limit - 0.86

CO2(%)
9/28/07 - 9.9
3/6/10 - 13.0
3/13/10 - 12.4

O2(%)
9/28/07 - 6.6
3/6/10 - 2.5
3/13/10 - 3.2

NOx(ppm)
9/28/07 - 834
3/6/10 - 2429 * fail
3/13/10 - 1126 * pass
Limit - 1146

Dilution(%)
9/28/07 - 10.8
3/6/10 - 13.0
3/13/10 - 12.4
Limit - > 6

RPM
9/28/07 - 1481
3/6/10 - 1640
3/13/10 - 1614

25 mph tests

HC (ppm)
9/28/07 - 40
3/6/10 - 24
3/13/10 - 17
Limit - 148

CO (%)
9/28/07 - 0.02
3/6/10 - 0.03
3/13/10 - 0.02
Limit - 0.94

CO2(%)
9/28/07 - 10.3
3/6/10 - 13.3
3/13/10 - 12.8

O2(%)
9/28/07 - 6.4
3/6/10 - 2.1
3/13/10 - 2.6

NOx(ppm)
9/28/07 - 1033
3/6/10 - 1831 * fail
3/13/10 - 1377 * fail
Limit - 1047

Dilution(%)
9/28/07 - 10.3
3/6/10 - 13.3
3/13/10 - 12.8
Limit - > 6

RPM
9/28/07 - 1452
3/6/10 - 1592
3/13/10 - 1150

No real mechanical changes that I can think of between the 2007 test and the 2010 test. Car seems to be burning cleaner, its just that the NOx is high. So what to do about it...

Two things I'm thinking about trying: First, I can get a couple gallons of E85 in there. Has that been proven to help a NOx problem? Second thing, I have a Translator Plus. I can retard the base timing by what, up to 6 degs? This will definitely reduce combustion temperatures and therefore NOx, correct? Can anyone verify? How much should I reduce the timing? As much as I can, or is 2-4 degs enough?

The final thing I was wondering about was the rpm at 25 mph for my re-test. With my everyday chip it was about 1600 rpm, but the emissions chip has the stock trans settings in it and it must have shifted into overdrive, dropping the rpm down to 1150. Would the higher rpms help? I could ask the tester to leave it in D, or I could try to get an emissions chip made up with my everyday chip's trans settings. Thoughts on that one?

Between those first two things, should that be enough to get over the hump? I would like to get that sticker, but I don't want to blow another $40 for nothing if those items might not help. I can drive outlaw until next Jan. if I have to - sticker is already a couple of years out of date, what's another year?

John

 

[pmoore4321]

You gotta roll outlaw!

 

[Jerryl]

I came to this section to pose a similar question, but since my questions are so close to the original poster's (hey Jerryl!) I'll just tack them on to this thread.

Two things I'm thinking about trying: First, I can get a couple gallons of E85 in there. Has that been proven to help a NOx problem? Second thing, I have a Translator Plus. I can retard the base timing by what, up to 6 degs? ....

John,
How are things?
As far as I know, the translator + timing setting only affects timing at WOT.
This must be a TX air thing.

 

[charlief1]

High combustion temps and high compression will cause NOX to be high. That's why I suggested using E-85 in the car. From what I've been reading you can use as much as a 50% mix without changing anything but I'd be happier with a lower mixture. Most gas is currently E-10 and if you have 5 gallons of "normal" gas and add 3 gallons of E-85 you should roughly have E-45 or a little lower mix which should cut the emissions down quite a bit. Hope this helps you some Jerryl.

 

[Jerryl]

Finally got around to look into a few things.

The EGR diaphragm is blown. (On order)
Also found a a small leak on the EGR signal hose. (Will be replacing the hoses and verify one way valve operation)
Will also replace the plugs.

If it does not pass after this, 30% E85 it is.
Thanks for all the advice. Will keep everyone posted.

 

[1987BuickGN]

Hmm, didnt know that. Does that mean we can drive cat-less too?

What about window tint, the guy that was going to inspect mine said he doesnt check for window tint on older vehicles like mine...
I know 25% or lighter is legal but i have 20%

To answer your question, the tint is not inspected under the emission part of the inspection process. It will be checked during the safety inspection part. See link.....

Texas Department of Public Safety - Frequently Asked Questions

As far as running w/out cats, it will not be checked during your inspection process. BUT, at any time if you are pulled over by any law enforcement agency (State Trooper,Local Police, Constable,etc.....) you can be ticketed for not having this equipment on your vehicle regardless if you were the owner of the time of when it was removed or not. People sometimes confuse what is the law and what will fail during a state inspection process.

 

[1987BuickGN]

I guess you guys in Texas don't have an emissions exempt. We here in PA. have it. If you drive your car less then 5,000 miles a year you don't have to get emissions. I get an emissions exempt sticker on my Cobra and GN.

They do have a low mileage waiver here also, they just make you put some time and effort into getting the required sticker before they issue one. It goes as follows,


--------------------------------------------------------------------------------

Low Mileage Waiver

There is a low mileage exemption for motorists who drive less than 5,000 miles/year. To qualify for this exemption you must:

Fail both the initial test and free retest
Incur $100 of emissions related repairs
Drive less than 5,000 miles/year
If you meet these qualifications then you would qualify for the low mileage waiver. Contact the DPS challenge station in your area for more information on the forms to complete.