Failed smog :(
#1
Failed smog :(
HI all,
I still consider myself a newbie so I figured I should ask rather than chase my tail.
First a little background.
I have a 90 burb w/ 350 AT 2WD 700r4
I've been trying to make it a little more fuel economical so I've been bumping up the timing and keeping the BLM's on average around 125.
I wanted to make sure this was not the cause for failing smog.
there are 2 emissions tests & I failed both.
The first is the 25MPH test
RPM was at 1280
Test Standard My reading
HC(PPM) 136 253 Fail
CO% 1.66 .64 Pass
CO2% 13.6 Info
O2% 0.9 info
Nox(ppm) 853 977 Fail
Dilution >6 14.2
The second is the 15MPH test
RPM was at 1371
Test Standard My reading
HC(PPM) 139 253 Fail
CO% 1.24 .75 Pass
CO2% 13.5 Info
O2% 1.1 Info
Nox(ppm) 926 1418 Fail
Dilution >6 14.2 Info
My SA table has lots of advance below 50 Map and gets closer to factory above that.
Example @1200 RPM X 40 Map Factory timing is 0x52H and I'm at 0x76H
Can that be the cause of failing? or do I need a new cat?
Thanks in advance for all your help.
EDIT:
Forgot to mention this is a TBI, Original bin was ASDU, 7747 ECU. The truck has leaky valve seals (It smokes after it's been sitting for several hours)
I still consider myself a newbie so I figured I should ask rather than chase my tail.
First a little background.
I have a 90 burb w/ 350 AT 2WD 700r4
I've been trying to make it a little more fuel economical so I've been bumping up the timing and keeping the BLM's on average around 125.
I wanted to make sure this was not the cause for failing smog.
there are 2 emissions tests & I failed both.
The first is the 25MPH test
RPM was at 1280
Test Standard My reading
HC(PPM) 136 253 Fail
CO% 1.66 .64 Pass
CO2% 13.6 Info
O2% 0.9 info
Nox(ppm) 853 977 Fail
Dilution >6 14.2
The second is the 15MPH test
RPM was at 1371
Test Standard My reading
HC(PPM) 139 253 Fail
CO% 1.24 .75 Pass
CO2% 13.5 Info
O2% 1.1 Info
Nox(ppm) 926 1418 Fail
Dilution >6 14.2 Info
My SA table has lots of advance below 50 Map and gets closer to factory above that.
Example @1200 RPM X 40 Map Factory timing is 0x52H and I'm at 0x76H
Can that be the cause of failing? or do I need a new cat?
Thanks in advance for all your help.
EDIT:
Forgot to mention this is a TBI, Original bin was ASDU, 7747 ECU. The truck has leaky valve seals (It smokes after it's been sitting for several hours)
Last edited by ggenovez; 07-17-2008 at 10:44 AM. Reason: Forgot some items
#2
Re: Failed smog :(
The first is the 25MPH test
RPM was at 1280
Test Standard My reading
HC(PPM) 136 253 Fail
CO% 1.66 .64 Pass
CO2% 13.6 Info
O2% 0.9 info
Nox(ppm) 853 977 Fail
Dilution >6 14.2
The second is the 15MPH test
RPM was at 1371
Test Standard My reading
HC(PPM) 139 253 Fail
CO% 1.24 .75 Pass
CO2% 13.5 Info
O2% 1.1 Info
Nox(ppm) 926 1418 Fail
Dilution >6 14.2 Info
My SA table has lots of advance below 50 Map and gets closer to factory above that.
Example @1200 RPM X 40 Map Factory timing is 0x52H and I'm at 0x76H
Can that be the cause of failing? or do I need a new cat?
It looks like the cat efficiency is low @ 15MPH test (O2=1.1%) I don't know on the 25MPH test-O2 is a bit lower. If it were up to me I would replace the cat & retest. What is your timing in degrees?
P.S. are you in Calif?
RPM was at 1280
Test Standard My reading
HC(PPM) 136 253 Fail
CO% 1.66 .64 Pass
CO2% 13.6 Info
O2% 0.9 info
Nox(ppm) 853 977 Fail
Dilution >6 14.2
The second is the 15MPH test
RPM was at 1371
Test Standard My reading
HC(PPM) 139 253 Fail
CO% 1.24 .75 Pass
CO2% 13.5 Info
O2% 1.1 Info
Nox(ppm) 926 1418 Fail
Dilution >6 14.2 Info
My SA table has lots of advance below 50 Map and gets closer to factory above that.
Example @1200 RPM X 40 Map Factory timing is 0x52H and I'm at 0x76H
Can that be the cause of failing? or do I need a new cat?
It looks like the cat efficiency is low @ 15MPH test (O2=1.1%) I don't know on the 25MPH test-O2 is a bit lower. If it were up to me I would replace the cat & retest. What is your timing in degrees?
P.S. are you in Calif?
#3
Re: Failed smog :(
No, I'm in Tx,
Not sure what you mean by my timing in degrees, but, idle timing is set 0 with the timing bypass disconnected. As for the example above, the calculated numbers are 28.83 for factory and I've set it to 41.48.
here is the 30-100 Map @1200 RPM if that help
43.59 42.54 41.48 40.78 38.67 35.86 31.99 28.48 25.31 23.20 18.98 16.87 15.12 11.95 11.95
Not sure what you mean by my timing in degrees, but, idle timing is set 0 with the timing bypass disconnected. As for the example above, the calculated numbers are 28.83 for factory and I've set it to 41.48.
here is the 30-100 Map @1200 RPM if that help
43.59 42.54 41.48 40.78 38.67 35.86 31.99 28.48 25.31 23.20 18.98 16.87 15.12 11.95 11.95
#4
Supreme Member
iTrader: (1)
Join Date: Mar 2000
Location: All over China, Iowa, and San Luis Obispo, CA
Posts: 1,692
Likes: 0
Received 1 Like
on
1 Post
Car: 92 Form, 91 Z28, 89 GTA, 86 Z28
Engine: 5.7 TPI, LG4
Transmission: 700R4, 700R4
Axle/Gears: 3.27, 2.73
Re: Failed smog :(
As long as you can burn your own chips, run the test with about 10 degrees total spark advance in the areas of the test. It'll help both HC and NOx.
Too much spark advance really hurts NOx, and also hurts HC some.
Too much spark advance really hurts NOx, and also hurts HC some.
#6
Supreme Member
iTrader: (1)
Join Date: Mar 2000
Location: All over China, Iowa, and San Luis Obispo, CA
Posts: 1,692
Likes: 0
Received 1 Like
on
1 Post
Car: 92 Form, 91 Z28, 89 GTA, 86 Z28
Engine: 5.7 TPI, LG4
Transmission: 700R4, 700R4
Axle/Gears: 3.27, 2.73
Re: Failed smog :(
If your HC's are 253, your cat is probably already toasted. A working cat will knock down HC's pretty well. Yours isn't. You might be experiencing a slight misfire, but it's pretty hard to find on a V8.
NOx won't hurt a cat though.
NOx won't hurt a cat though.
#7
Re: Failed smog :(
No, I'm in Tx,
Not sure what you mean by my timing in degrees, but, idle timing is set 0 with the timing bypass disconnected. As for the example above, the calculated numbers are 28.83 for factory and I've set it to 41.48.
here is the 30-100 Map @1200 RPM if that help
43.59 42.54 41.48 40.78 38.67 35.86 31.99 28.48 25.31 23.20 18.98 16.87 15.12 11.95 11.95
Not sure what you mean by my timing in degrees, but, idle timing is set 0 with the timing bypass disconnected. As for the example above, the calculated numbers are 28.83 for factory and I've set it to 41.48.
here is the 30-100 Map @1200 RPM if that help
43.59 42.54 41.48 40.78 38.67 35.86 31.99 28.48 25.31 23.20 18.98 16.87 15.12 11.95 11.95
Trending Topics
#10
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
Ok you passed emissions with nice numbers. Something to consider though. Why are you running 41* of timing with Swirl Ports. They definately don't need it.
#11
TGO Supporter
Join Date: Jul 1999
Location: The Bone Yard
Posts: 10,907
Likes: 0
Received 3 Likes
on
3 Posts
Car: Death Mobile
Engine: 666 c.i.
Re: Failed smog :(
If BOTH your HC and NOx are failing, there is NOTHING you can do with tuning to make it pass.
With tuning, you can "trade" HC for NOx and vice versa. BUT NOT BOTH.
This suggests that possibly something mechanical is not right. Such as a catalytic converter and/or EGR.
Too many HCs are usually a cat and too many NOx are usually an EGR.
With tuning, you can "trade" HC for NOx and vice versa. BUT NOT BOTH.
This suggests that possibly something mechanical is not right. Such as a catalytic converter and/or EGR.
Too many HCs are usually a cat and too many NOx are usually an EGR.
#12
Re: Failed smog :(
Hey Fast,
I was bumping up the timing to try to get it more fuel economical. I was getting 13mpg on the highway.
Intersting table you attached, its more retarded than the asdu I started with,
So I kept on bumping it until I saw pings. Did I do something wrong?
Here is the SA I'm planning on running tomorrow. Are there any concerns with running too much of a SA?
Any feedback would be greatly appriciated.
I was bumping up the timing to try to get it more fuel economical. I was getting 13mpg on the highway.
Intersting table you attached, its more retarded than the asdu I started with,
So I kept on bumping it until I saw pings. Did I do something wrong?
Here is the SA I'm planning on running tomorrow. Are there any concerns with running too much of a SA?
Any feedback would be greatly appriciated.
#13
Re: Failed smog :(
Thanks Grim,
I'll take a look at the EGR in a couple of months when the weather cools off. It's starting to warm up right now, 102'F today, it's only gonna get worst.
I'll take a look at the EGR in a couple of months when the weather cools off. It's starting to warm up right now, 102'F today, it's only gonna get worst.
#14
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
Hey Fast,
I was bumping up the timing to try to get it more fuel economical. I was getting 13mpg on the highway.
Intersting table you attached, its more retarded than the asdu I started with, Attachment 160698
So I kept on bumping it until I saw pings. Did I do something wrong?
Here is the SA I'm planning on running tomorrow. Are there any concerns with running too much of a SA?
Attachment 160699
Any feedback would be greatly appriciated.
I was bumping up the timing to try to get it more fuel economical. I was getting 13mpg on the highway.
Intersting table you attached, its more retarded than the asdu I started with, Attachment 160698
So I kept on bumping it until I saw pings. Did I do something wrong?
Here is the SA I'm planning on running tomorrow. Are there any concerns with running too much of a SA?
Attachment 160699
Any feedback would be greatly appriciated.
Too much spark advance will actually hurt fuel mileage and could hurt the engine. All the values you have higher than 42* are limited to 42* by the ECM. The actual distributor can only advance the timing a little over 42* BTDC before it starts crossfiring to the next cylinder. If you advance the distributer 6* BTDC it will allow you to run 48* advance (this is why TPI cars are run at 6*, they have 47* programmed into some load/rpm areas).
#16
Re: Failed smog :(
Ok, I'll have to look for another bin, that shows something closer to yours.
Yeah, the weather is very similar to DFW, I'm in Bedford
----------
BTW, how much advance is too much?
Yeah, the weather is very similar to DFW, I'm in Bedford
----------
BTW, how much advance is too much?
Last edited by ggenovez; 07-22-2008 at 09:42 PM. Reason: Automerged Doublepost
#17
Re: Failed smog :(
Ok, I'm looking at the moates ASDU file http://www.moates.net/files/1)%20Sto...5/asdu9567.bin and It loos like the same one that I have.
I'm seriously confused.
I'm seriously confused.
#18
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
Really, I am in Bedford too on the Hurst border. I live about 2 minutes from 121 and Bedford-Euless Rd.
You have probably seen my old Red/Grey van running around and not even realized it. Its a loud SOB and pretty darn quick too.
----------
Ok, I'm looking at the moates ASDU file http://www.moates.net/files/1)%20Sto...5/asdu9567.bin and It loos like the same one that I have.
I'm seriously confused.
I'm seriously confused.
Last edited by Fast355; 07-22-2008 at 10:16 PM. Reason: Automerged Doublepost
#19
Re: Failed smog :(
LOL, Big white burb with a blue stripe running through it. Never miss it in a parking lot
I'm off 121 and harwood. Yeah spitting distance from eachother.
I'll try to find another XDF.
So I'm probably not running 42' advance...
I'm off 121 and harwood. Yeah spitting distance from eachother.
I'll try to find another XDF.
So I'm probably not running 42' advance...
#20
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
----------
If you have AIM shoot me an IM. I can send you the best $42 XDF that I have. Red83brick
Last edited by Fast355; 07-22-2008 at 10:25 PM. Reason: Automerged Doublepost
#22
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
More spark advance does not mean more MPG. A certain amount in a few places can help. However it is easier to find fuel economy in the VE, AE, DE and DFCO than the spark tables on a stock engine.
#23
Re: Failed smog :(
Considering I have 26 posts (mostly from this tread) and you have over 4K I'm all ears
Is there a primer or anything that I can read or somthing?
Thanks
Is there a primer or anything that I can read or somthing?
Thanks
#24
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
In all honesty though I have tuned ALOT of engines in different chassis.
The TBI tuning thread in the TBI forum has ALOT of information in it.
Basically
1.) Tune VE tables using BLM correction (EGR and CCP disabled)
2.) Rough in spark table
3.) Tune AE
4.) Tune DE
5.) Fine tune VE table and spark
6.) Enable EGR and correct tables
7.) Adjust TCC settings
#27
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
I didn't get into this in my previous posts, but this is what I am running in a vehicle of similar weight and aerodynamic properties. I am sure you suburban has some crazy tall rear gear ratio as well. GM loved to put 3.08s even with the 700r4. If you are lucky you get 3.42s. Mine has GQ1 which is the standard gear ratio which for a 1983 G20 Van was 3.08s. Great fun those are, lol. My 700r4 is setup to shift at 4,800-5,000 rpm @ WOT and it does the 1-2 shift at ~41 mph and the 2-3 upshift at ~80 mph. My point is I am running the stock timing table (a few stock numbers were negative but the 7730 would not work with them so they are 0, and the highway spark mode has been enabled) with my engine and having great luck with it. You can listen to how quick it runs up the gears up to speed especially since I stalled it up to about 1,300 rpm before smacking the throttle. Also notice how nice and flat the torque curve is the fuel table depicts this well. I have a feeling you will find a very flat VE table as well if you are tuned close to what the engine needs.
http://s243.photobucket.com/albums/f...t=101_1403.flv
Even from a 25 mph roll in 2nd gear it picks up quick at low rpms (Notice Grubbs and Bell HS?).
http://s243.photobucket.com/albums/f...t=101_1400.flv
http://s243.photobucket.com/albums/f...t=101_1403.flv
Even from a 25 mph roll in 2nd gear it picks up quick at low rpms (Notice Grubbs and Bell HS?).
http://s243.photobucket.com/albums/f...t=101_1400.flv
Last edited by Fast355; 07-23-2008 at 09:30 PM.
#28
Re: Failed smog :(
Stock rear end I beleive was a 3.42. Now it's a 3.08 off a 87 burb. Speedo is off by 10%
I'm still looking up info for AE but I have brought the timing back to stock...
YOu have quite a collection of videos and picks. I love the supper charged caddy. All yours?
I take it the 305 TPI in the van is not stock... I take it you did the conversion yourself?
I'm still looking up info for AE but I have brought the timing back to stock...
YOu have quite a collection of videos and picks. I love the supper charged caddy. All yours?
I take it the 305 TPI in the van is not stock... I take it you did the conversion yourself?
#29
Supreme Member
iTrader: (2)
Join Date: Jan 2005
Location: Hurst, Texas
Posts: 10,041
Received 395 Likes
on
337 Posts
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: Failed smog :(
Stock rear end I beleive was a 3.42. Now it's a 3.08 off a 87 burb. Speedo is off by 10%
I'm still looking up info for AE but I have brought the timing back to stock...
YOu have quite a collection of videos and picks. I love the supper charged caddy. All yours?
I take it the 305 TPI in the van is not stock... I take it you did the conversion yourself?
I'm still looking up info for AE but I have brought the timing back to stock...
YOu have quite a collection of videos and picks. I love the supper charged caddy. All yours?
I take it the 305 TPI in the van is not stock... I take it you did the conversion yourself?
The Dodge Truck, the S10, and the Van are mine. The Vans transformation is pretty much shown through the pictures.
I did the TPI conversion myself. The 305 is only mildly built, but still has stock 187 casting 305 swirl ports on it. Thorley Tri-Y headers, Mild hydraulic roller cam, stock flattop pistons, balanced and blueprinted. I also have total seal rings and other good parts. This build was all about maximizing HP/TQ and fuel mileage.
For AE you want just enough fuel for a smooth take off as you move the throttle. I often find that these stock setups drown the engine in fuel.
I'm picking up a Jack n Box burger and will be right back to answer any other questions.
#30
Re: Failed smog :(
Heh heh heh,
We call it crack in the box. I love their chiabata bacon burgers.
I guess the problem with AE is I don't know what I'm looking for. I think I have a smooth take off as is.
We probably need to get together for a beer or something so I can get a better understanding.
Thanks again.
We call it crack in the box. I love their chiabata bacon burgers.
I guess the problem with AE is I don't know what I'm looking for. I think I have a smooth take off as is.
We probably need to get together for a beer or something so I can get a better understanding.
Thanks again.
Thread
Thread Starter
Forum
Replies
Last Post