88 GTU failed emissions
05-12-12, 09:45 AM
#26
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get a new cat..quit fartin with an old cat.
and try 1/8 of a tank of gas and 1 gallon of methyl hydrate.
get the car NICE and hot( like a 20 minute run) then dump the methyl hydrate into the tank.
do the test..then go and FILL up.(the methyl hydrate is not really friendly so it needs to be diluted.)
and try 1/8 of a tank of gas and 1 gallon of methyl hydrate.
get the car NICE and hot( like a 20 minute run) then dump the methyl hydrate into the tank.
do the test..then go and FILL up.(the methyl hydrate is not really friendly so it needs to be diluted.)
05-12-12, 09:54 AM
#27
Call me captain obvious, but did you try putting the smog pump and ACV back on, or if they're still on there making sure they work? You know, the parts that were designed to make your car pass emissions? I know they are a pain in the *** but you live in CA and that just comes with the territory. Oh and get a new cat.
05-12-12, 01:23 PM
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Call me captain obvious, but did you try putting the smog pump and ACV back on, or if they're still on there making sure they work? You know, the parts that were designed to make your car pass emissions? I know they are a pain in the *** but you live in CA and that just comes with the territory. Oh and get a new cat.
So this shop today...I set the variable to the middle, seemed logical to me. Took it to this guy. I notice that the first thing he does is run it on the rollers, only idle time is long enough to enter info. The other guy I been taking it to, did all inspections and evap tests first while the car idled.
So it ran through the 15mph and 25mph tests FAST! The guy had a big smile on his face. Then at the very end, he asked where my check engine light was.
Me, "It's the stop lamp in the light cluster"
Him, "No, it's supposed to say check engine"
Me, "No, that's not till like 1990"
Him, "It's 1989."
Me, "This is an 88"
Him, "No its an 89"
Me, "This is my baby, it's an 88 GTU, the first and only year this particular trim was available. It's an 88." (the 88 GTU is different than the 89 GTU, more like the 89 GTUs)
Him, "..."
He looked at the sticker on the door. Apparently it was in the "system" by someone else as an 89 so it was asking for a CEL. He reregistered it as an 88, but had to rerun it on the rollers. All fine and dandy except it had been sitting OFF this whole time, 10 minutes or so while he checked plugs and evap and timing, etc (none of which the other guy did). Apparently I hid the IAT plug well.
Well, it failed again. This time worse, cause apparently 1988 cars are required lower emissions?! WTF?!
**** it. Cuttin my losses and buying a new cat. Also gonna do the denatured alcohol. Does anyone make a test pipe that bypasses the first two precats? Or is there a 2-1 header that will bolt in?
At least this guy's givin me free retest.
5/12/12:
15 mph:
RPM - 1802
%CO2 - 14.4
%O2 - 0.5
HC - 200 (85 max) FAILED
CO - 0.31 (0.54 max)
NO - 86 (565 max)
25 mph:
RPM - 2938
%CO2 - 14.6
%O2 - 0.1
HC - 97 (67 max) FAILED
CO - 0.45 (0.34 max)
NO - 61 (522 max)
Last edited by Jet-Lee; 05-12-12 at 01:34 PM.
05-12-12, 11:07 PM
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holy cow, i had something like that happen when i smogged my 79 Rx7. since its a THERMAL reactor, i don't really know how it works, so i had my guy pretest it, and it passed with flying colors.
so he shut it off to enter all the BS in the computer.
he starts it up 10 minutes later and it almost failed! the THERMAL reactor needs heat! but so does a cat! i'd be kind of mad if my smog guy turned the car off before the test.
so he shut it off to enter all the BS in the computer.
he starts it up 10 minutes later and it almost failed! the THERMAL reactor needs heat! but so does a cat! i'd be kind of mad if my smog guy turned the car off before the test.
05-12-12, 11:26 PM
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Well he did it correct the first time, and everything looked great. Then come to find out that someone somewhere entered the wrong year. This guy being super-legit fixed the info, but the computer required him to re-run the car. By the time he re-ran it, it had cooled down.
This is just bullshit.
Limits for 15/25mph:
1989
HC: 118/93
CO: .75/.63
NO: 799/738
1988
HC: 85/67
CO: .54/.45
NO: 565/522
WTF? Why does the older car have stricter limits?? Last I checked, 100ppm was 100ppm whether it came from a 2012 or a 1912 model car. I think they're trying to drive (pardon the pun) consumers to get rid of their old cars and dump money into economy by buying new. However most of that money actually goes to foreign economies because people will want to get something "reliable" if they're having to replace something that obviously isn't.
I hate this state with a passion. If it wasn't for mom's cancer I never would've came back.
This is just bullshit.
Limits for 15/25mph:
1989
HC: 118/93
CO: .75/.63
NO: 799/738
1988
HC: 85/67
CO: .54/.45
NO: 565/522
WTF? Why does the older car have stricter limits?? Last I checked, 100ppm was 100ppm whether it came from a 2012 or a 1912 model car. I think they're trying to drive (pardon the pun) consumers to get rid of their old cars and dump money into economy by buying new. However most of that money actually goes to foreign economies because people will want to get something "reliable" if they're having to replace something that obviously isn't.
I hate this state with a passion. If it wasn't for mom's cancer I never would've came back.
05-13-12, 11:46 AM
#32
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i ran into that last year, my friends FC passed smog easily, and then last time it failed with high NOX, and comparing the NOX the car tested the same both times, but the test changed!
the o2 sensor actually was fried, and a new one fixed it, but still
that one does HC in the 20's, co is somewhere around .006 and NOX went from 800 to 231....
car is totally stock, and if i showed you the main cat you wouldn't believe it still works!
the o2 sensor actually was fried, and a new one fixed it, but still
that one does HC in the 20's, co is somewhere around .006 and NOX went from 800 to 231....
car is totally stock, and if i showed you the main cat you wouldn't believe it still works!
05-13-12, 02:12 PM
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I'm sure having the two pre-cats gutted, and a large streetport has a lot to do with it.
With the pre-cats being gutted, it allows the exhaust a place to expand and cool down, not once but twice, so it's not heating the main cat as efficiently as it could.
But still, tightening it down more and more is just bullshit. Maybe I'll see about sleeving the pre-cats so it's straight through without the expansion, keeping the exhaust hotter.
With the pre-cats being gutted, it allows the exhaust a place to expand and cool down, not once but twice, so it's not heating the main cat as efficiently as it could.
But still, tightening it down more and more is just bullshit. Maybe I'll see about sleeving the pre-cats so it's straight through without the expansion, keeping the exhaust hotter.
05-13-12, 07:41 PM
#34
You should put the timing back to stock. It's lowering your exhaust temperatures, and just generally hurts emissions. There's a reason why the stock base timing is -5L -20T.
Below is a chart from an old Mazda study on an early 12A. I know it's not exactly the same, but the basic trend line holds true. Look right across the X axis. That's more timing advance. The line I've put in red is your HC trend line. It goes up when you advance the timing. If you look at those dashed lines at the bottom, it shows that your exhaust temperature goes down when you advance the timing. Lowering the exhaust temperature hurts your catalyst efficiency.
Your cat situation is also part of the problem. You've got the two precats gutted and I'm sure your main cat is down on efficiency. Are you sure your port air system is working right or do you just have the airpump putting right into the cat?
Below is a chart from an old Mazda study on an early 12A. I know it's not exactly the same, but the basic trend line holds true. Look right across the X axis. That's more timing advance. The line I've put in red is your HC trend line. It goes up when you advance the timing. If you look at those dashed lines at the bottom, it shows that your exhaust temperature goes down when you advance the timing. Lowering the exhaust temperature hurts your catalyst efficiency.
Your cat situation is also part of the problem. You've got the two precats gutted and I'm sure your main cat is down on efficiency. Are you sure your port air system is working right or do you just have the airpump putting right into the cat?
05-14-12, 09:33 AM
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That's some good info! Never seen anything like that before.
So by advancing my CAS by 10º, I basically dropped my EGT's ~50ºF which raised my HC's by ~200ppm and raised NOx by ~100ppm.
The theory looks solid. In practice it's not exact, but the trend is there.
I haven't checked the port air system. Since the car passed smog fine before the rebuild, I left all the emissions stuff alone, just cleaned gasket surfaces and obvious carbon buildup and bolted it back on. I assume it's working fine or my numbers would be a lot higher.
So by advancing my CAS by 10º, I basically dropped my EGT's ~50ºF which raised my HC's by ~200ppm and raised NOx by ~100ppm.
The theory looks solid. In practice it's not exact, but the trend is there.
I haven't checked the port air system. Since the car passed smog fine before the rebuild, I left all the emissions stuff alone, just cleaned gasket surfaces and obvious carbon buildup and bolted it back on. I assume it's working fine or my numbers would be a lot higher.
05-16-12, 08:54 PM
#36
05-16-12, 10:00 PM
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You should put the timing back to stock. It's lowering your exhaust temperatures, and just generally hurts emissions. There's a reason why the stock base timing is -5L -20T.
Below is a chart from an old Mazda study on an early 12A. I know it's not exactly the same, but the basic trend line holds true. Look right across the X axis. That's more timing advance. The line I've put in red is your HC trend line. It goes up when you advance the timing. If you look at those dashed lines at the bottom, it shows that your exhaust temperature goes down when you advance the timing. Lowering the exhaust temperature hurts your catalyst efficiency.
Your cat situation is also part of the problem. You've got the two precats gutted and I'm sure your main cat is down on efficiency. Are you sure your port air system is working right or do you just have the airpump putting right into the cat?
Below is a chart from an old Mazda study on an early 12A. I know it's not exactly the same, but the basic trend line holds true. Look right across the X axis. That's more timing advance. The line I've put in red is your HC trend line. It goes up when you advance the timing. If you look at those dashed lines at the bottom, it shows that your exhaust temperature goes down when you advance the timing. Lowering the exhaust temperature hurts your catalyst efficiency.
Your cat situation is also part of the problem. You've got the two precats gutted and I'm sure your main cat is down on efficiency. Are you sure your port air system is working right or do you just have the airpump putting right into the cat?
so i put it back to stock, and HC and Co didn't move but NOX does, actually maybe that verifies the chart. it might also be a little different because i'm measuring in the tailpipe after a cat, and @1000HC's they are measuring somewhere else.
what RPM is that chart at?
05-17-12, 07:46 AM
#39
Here's your problem. It's got a large port job. You've got more overlap. You are showing us readings from a non ported motor vs a ported one. There's no surprise whatsoever that things are different and is completely normal. It's going to have a harder time passing emissions now. It's not to say that it won't but it won't be as easy as stock motor. Emissions standards vary across the country so it may be easier to pass in one state vs another that has them.
05-17-12, 09:39 AM
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Sooo....any suggestions?
I've also shown the numbers of each test with this setup, where the HC's keep climbing.
Going again today after work, with the new (not leaking) catalytic converter and a gallon of denatured alcohol in the tank. It's sitting on about a 1/4 tank right now, it'll be down to 1/8 by the time I get home, go get DNA, then get to the test center.
I've also shown the numbers of each test with this setup, where the HC's keep climbing.
Going again today after work, with the new (not leaking) catalytic converter and a gallon of denatured alcohol in the tank. It's sitting on about a 1/4 tank right now, it'll be down to 1/8 by the time I get home, go get DNA, then get to the test center.
Last edited by Jet-Lee; 05-17-12 at 09:47 AM.
05-17-12, 10:53 AM
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if you wanted to check port air, the ACV blows into a series of mufflers (not kidding) and exits on the right front kind of where the undertray meets the wheel well cover, put your finger over the hose, if there is any air coming out at idle, its bad. it should actually not have any air coming out of it until about 2500rpm (it depends on throttle position, so the TPS is important)
05-17-12, 11:27 AM
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TPS has been checked, rechecked and checked again.
I'll look for that hose to make sure. Is it just open to the atmosphere???
-EDIT-
Is it that big nipple pointing straight at the camera, that has the hose (in the next pic) connected to it?
Is this the hose that should have no air at idle?
I'll look for that hose to make sure. Is it just open to the atmosphere???
-EDIT-
Is it that big nipple pointing straight at the camera, that has the hose (in the next pic) connected to it?
Is this the hose that should have no air at idle?
Last edited by Jet-Lee; 05-17-12 at 11:38 AM.
05-17-12, 02:47 PM
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TPS has been checked, rechecked and checked again.
I'll look for that hose to make sure. Is it just open to the atmosphere???
-EDIT-
Is it that big nipple pointing straight at the camera, that has the hose (in the next pic) connected to it?
Is this the hose that should have no air at idle?
I'll look for that hose to make sure. Is it just open to the atmosphere???
-EDIT-
Is it that big nipple pointing straight at the camera, that has the hose (in the next pic) connected to it?
Is this the hose that should have no air at idle?
05-18-12, 10:17 AM
#49
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Of course! I also reset the timing to 0º advance and double checked the TPS.
5/17/12:
15 mph:
RPM - 1767
%CO2 - 14.3
%O2 - 0.5
HC - 36 (85 max)
CO - 0.33 (0.54 max)
NO - 32 (565 max)
25 mph:
RPM - 2875
%CO2 - 14.3
%O2 - 0.5
HC - 34 (67 max)
CO - 0.28 (0.34 max)
NO - 28 (522 max)
5/17/12:
15 mph:
RPM - 1767
%CO2 - 14.3
%O2 - 0.5
HC - 36 (85 max)
CO - 0.33 (0.54 max)
NO - 32 (565 max)
25 mph:
RPM - 2875
%CO2 - 14.3
%O2 - 0.5
HC - 34 (67 max)
CO - 0.28 (0.34 max)
NO - 28 (522 max)
05-18-12, 10:50 AM
#50
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Of course! I also reset the timing to 0º advance and double checked the TPS.
5/17/12:
15 mph:
RPM - 1767
%CO2 - 14.3
%O2 - 0.5
HC - 36 (85 max)
CO - 0.33 (0.54 max)
NO - 32 (565 max)
25 mph:
RPM - 2875
%CO2 - 14.3
%O2 - 0.5
HC - 34 (67 max)
CO - 0.28 (0.34 max)
NO - 28 (522 max)
5/17/12:
15 mph:
RPM - 1767
%CO2 - 14.3
%O2 - 0.5
HC - 36 (85 max)
CO - 0.33 (0.54 max)
NO - 32 (565 max)
25 mph:
RPM - 2875
%CO2 - 14.3
%O2 - 0.5
HC - 34 (67 max)
CO - 0.28 (0.34 max)
NO - 28 (522 max)