Colorado Emissions Help

#1
I have an 87 Turbo and am in the process of getting it back on the road. It's been sitting for some time getting paint and body work done. I changed all the fluids and drove on the highway for about an hour before the first test. It failed for HC at 3.1133 and CO at 22.7273. I changed the O2 sensor and had a new CAT installed. That took the HC down below the limit but CO shot up to 29.4298. The motor is mostly stock with the exception of 40lb injectors and a chip that I got from Poston 10-15 years ago. I'm getting ready to do some upgrades but just want to get it legal while I approval from the boss. :)

If anyone has any suggestions it would be much appreciated. Or if you know a good shop in the Denver area to take it to. I don't have as much time these days to work on it with a growing family.
 
#4
Great video to give you an overview of what is going on with HC, CO and NOX.

My guess for your car: You are rich, possibly due to the Poston chip or higher fuel pressure.
If this were my car, I would get an emissions chip from Eric and go from there: https://www.turbotweakstore.com/ProductDetails.asp?ProductCode=1001
I figured it was likely running rich but since it used to pass with the chip and injectors in the past that something else was likely wrong. Maybe the limits have been lowered in Colorado recently. Can a vacuum leak cause it to run rich? Is there a way to adjust the fuel pressure on a stock regulator? I'll pick up one of the emissions chip and give it a shot. Thank you for the help.
 

Heskahoka

Supporting Member
#5
I figured it was likely running rich but since it used to pass with the chip and injectors in the past that something else was likely wrong. Maybe the limits have been lowered in Colorado recently. Can a vacuum leak cause it to run rich? Is there a way to adjust the fuel pressure on a stock regulator? I'll pick up one of the emissions chip and give it a shot. Thank you for the help.
You cannot adjust the stock regulator. The only thing you can do is pull the vacuum line off the regulator and make sure there is no fuel coming through the vacuum port (bad diaphragm).
A Vacuum leak will usually cause higher HC, not higher CO. Higher CO is usually incomplete combustion.
If you passed before on the existing chip, I would lean towards spark plugs or leaky injectors. Spark plugs are cheap and probably need changing anyways.
Wait until you get the emissions chip and make sure you have fresh gas. A little E85 mixed in with fresh gas would not hurt either.
 
#7
Mine failed to pass the first time. The second time it sailed right through. The only thing different was the above.
I had a fresh oil change and fresh gas. I also drove on the highway for about an hour to make sure the cat was hot. I appreciate it though.
 
#8
You cannot adjust the stock regulator. The only thing you can do is pull the vacuum line off the regulator and make sure there is no fuel coming through the vacuum port (bad diaphragm).
A Vacuum leak will usually cause higher HC, not higher CO. Higher CO is usually incomplete combustion.
If you passed before on the existing chip, I would lean towards spark plugs or leaky injectors. Spark plugs are cheap and probably need changing anyways.
Wait until you get the emissions chip and make sure you have fresh gas. A little E85 mixed in with fresh gas would not hurt either.
I see. The plugs should probably be changed anyway. I'll start there and also get the emissions chip. I appreciate the help.
 

1952ray

Scrambled Dog
#10
I have an 87 Turbo and am in the process of getting it back on the road. It's been sitting for some time getting paint and body work done. I changed all the fluids and drove on the highway for about an hour before the first test. It failed for HC at 3.1133 and CO at 22.7273. I changed the O2 sensor and had a new CAT installed. That took the HC down below the limit but CO shot up to 29.4298. The motor is mostly stock with the exception of 40lb injectors and a chip that I got from Poston 10-15 years ago. I'm getting ready to do some upgrades but just want to get it legal while I approval from the boss. :)

If anyone has any suggestions it would be much appreciated. Or if you know a good shop in the Denver area to take it to. I don't have as much time these days to work on it with a growing family.
Or you could move here, SC as this state has no inspection laws of any kind. You ask someone down here about emissions, you will get a strange look. And a what’s that.
 
#11
Would be a shame if you zip tied some stuff out of the way while working on the car and the zip tie got left in a place such that the throttle blade only opened halfway. On the rolling im240 test years ago they would go WOT...
 
#13
Best you can do is make sure all emission related components are in place a working properly. And get a emission chip from Bob or Eric.
Hey there, I’m new on the blog. I do have an emissions chip from Eric. It works great ! I live in California where the smog rules are harsh. I did find out in some counties in CA do not require a smog.
 
#14
Hey there, I’m new on the blog. I do have an emissions chip from Eric. It works great ! I live in California where the smog rules are harsh. I did find out in some counties in CA do not require a smog.
I've ordered the emissions chip from Eric and I'm switching out the plugs and wires since its been awhile. Hopefully that does the trick. Thanks for the help.

Sent from my SM-G950U using Tapatalk
 
#15
I've ordered the emissions chip from Eric and I'm switching out the plugs and wires since its been awhile. Hopefully that does the trick. Thanks for the help.

Sent from my SM-G950U using Tapatalk
When getting your emissions checked “ keep your car running “ this way the catalytic converter stays hot. Important! Plugs,wires, gas and a nice oil change before getting a smog. Especially here in CA
 

jiho2

Sporadic Poster
#16
Here in California, the machine will prompt the tech to "condition" the cat for you by racing the motor for a few minutes.
 

jiho2

Sporadic Poster
#17
Is the car a "native" Colorado car, or was it brought in from another state? If native, has the original throttle body been replaced?