I just can't pass emissions!

[Alloydude]

Vacuum leak is all I can come up with. Maybe around the mating surfaces of your plenum or intake runners or even loose intake to head bolts. It’s too bad the smog technicians aren’t more helpful in steering you down the right path towards emission compliance.

 

[Vettefan87]

I have the stock regulator on there. But I will check the fuel pressure and see what it says. My book says that it should read somewhere in the 35-39 PSI area. Is that correct?

The shop putting my motor back in set it at 47lbs. I am not sure if that was set with the vaccum line one or off. I hope you can get it fixed, keep us updated.


Justin

 

[vette-dude]

Have you tried cleaning the Throttle body? Take off the hose and open up the butterflies and using a flashlight take a look. If it ain't shiny in there it is dirty. Use Throttle Body Cleaner only and a soft bristled brush and clean it up. Also run a can or two of SEAFOAM (to clean up the injectors) through the system once your done. Make sure the Gas you put in before the smog check is not a winterized mixture. I always put a can of 101 Octane in mine before a smog check. Hope this helps.


Randy

 

[Edmond]

Have you tried cleaning the Throttle body? Take off the hose and open up the butterflies and using a flashlight take a look. If it ain't shiny in there it is dirty. Use Throttle Body Cleaner only and a soft bristled brush and clean it up. Also run a can or two of SEAFOAM (to clean up the injectors) through the system once your done. Make sure the Gas you put in before the smog check is not a winterized mixture. I always put a can of 101 Octane in mine before a smog check. Hope this helps.


Randy

I will do that this weekend. I never even considered the TB.

 

[Mad-Mic]

Edmond,


i'm in the same boat. High hydrocarbons. i know why mine didn't pass but she is definetly running real rich for somereason now. i think it's time to pull the intake and put the AFPR on so i can lean her out some.

you can actually smell the fuel from my car when you romp on it.

 

[Greg@NASA]

Edmond, try the vacuum system first, I am going thru the same thing with the Porsche right now.High readings can also be averaged out by running the test at higher rpm.Try getting the tech to take the higher speed reading in 2nd gear???Just a thought.


Greg

 

[Edmond]

Edmond,


i'm in the same boat. High hydrocarbons. i know why mine didn't pass but she is definetly running real rich for somereason now. i think it's time to pull the intake and put the AFPR on so i can lean her out some.

you can actually smell the fuel from my car when you romp on it.

Mic,

I can smell the fuel when I'm standing behind the mufflers.

 

[Edmond]

Edmond, try the vacuum system first, I am going thru the same thing with the Porsche right now.High readings can also be averaged out by running the test at higher rpm.Try getting the tech to take the higher speed reading in 2nd gear???Just a thought.


Greg

I never even thought of that. But with the ridiculous rules and regulations, I doubt they would even consider that.

 

[Mad-Mic]

Mic,

I can smell the fuel when I'm standing behind the mufflers.

thats most of your problem right there.

dump the bosch plat +4's cause they are junk. i bet when you pull them out they will be gooky black. add a fresh set of AC Delco or AC Delco rapid fires gapped at .040 or .045 and index them to the intake valve. every little bit counts.

i know i wasn't gonna pass cause i am running too much timing and never set it back down to 6*. you can also run less timing than 6* which will help also.

if your close on the #'s throw 2 bottles of 90% ispropynol (sp) alcohol in the tank on a 1/4 tank of fuel. this will also lean the car out some.

 

[MoeJr]

I definitely agree that a good combustion chamber cleaning is in order. I would make sure all the tuning parameters are where they are supposed to be and then use a can of GM top engine cleaner on it to get the chambers as clean as can be. U should not be having a problem passing emissions even with a better chip in it. My 87 GN passed emissions test without cat and that car was modded to run low 12's. I didn't have to touch the fuel reg or anything. I think you'll be fine with just taking car of some tuning details and giving the engine a good cleaning with the GM stuff I mentioned above. U gotta change your oil after your done cleaning it though.

 

[crash1mac]

you might have a injector stuck open.ALso change your plugs.My 89 had a 160 stat and k&n 24# fms injectors and no cats passed with no problem and she had 120k on the odometer.It can hurt to swap injectors and clean the plenum and TB.
If you are going to replace injectors clean everything an and reseal.

 

[Edmond]

thats most of your problem right there.

dump the bosch plat +4's cause they are junk. i bet when you pull them out they will be gooky black. add a fresh set of AC Delco or AC Delco rapid fires gapped at .040 or .045 and index them to the intake valve. every little bit counts.

i know i wasn't gonna pass cause i am running too much timing and never set it back down to 6*. you can also run less timing than 6* which will help also.

if your close on the #'s throw 2 bottles of 90% ispropynol (sp) alcohol in the tank on a 1/4 tank of fuel. this will also lean the car out some.

Mic,

I pulled one of the Bosch +4's out today and it was fouled with fuel. I bought a set of Delco FR5LS and I'm putting them in after this post and lunch. Hotdogs anyone?

My neighbor will probably help me tomorrow with the timing. He has a timing light and I have no idea what I'm doing with timing.

Are you talking about Heet? I put 6 bottles of that stuff in before I went to test on Wednesday. I'm thinking of running it down to a little less than a 1/4 tank, put some Heet in there, and then go in for the test.

I have 2 more tests and as long as I can show improvement with every test and spend $450 in repairs (which I'm getting close to), I can get a 2 year waiver.

 

[Edmond]

The shop putting my motor back in set it at 47lbs. I am not sure if that was set with the vaccum line one or off. I hope you can get it fixed, keep us updated.


Justin

Justin,

I checked the fuel pressure and it was reading at 38/39 pounds. My manual says that it should read in the 34-39 range so I think I'm okay with the fuel pressure. Fortunately, that means I won't have to change the fuel pressure regulator. Taking the plenum and all that stuff off is a PITA, but I think I can get it done in 10 minutes.

Fuel pressure is okay, I'm changing plugs in a few minutes, running it down to test again and see if there is an improvement. Like Mic said, every little bit helps.

 

[Edmond]

I changed out the spark plugs to Delco's. One of the Bosch +4's looked really bad:

It was the driver side, closest to the rear, #7 I think. It didn't seem like that plug could fire anymore, it was all clogged up with black deposits.

I also checked the timing and it was at 2*. We set it to 7* and I took it in for another test. I put 9 bottles of Heet in it to lean out the mix. This test came back much better. The hydrocarbons were higher at 2.03 GPM, compared to 1.9 last time but I think that was because I went straight to the testing facility. The big improvement was in the carbon monoxide. I tested 17 GPM, compared to 26 GPM last time.

I think that if the car was running as hot as I could've gotten it, I could've passed. However, I went to test anyway because if I keep showing improvement after all 3 eligible tests, I can get a 2 year waiver. I'm still hoping to pass on the last attempt, which will probably be in a week or two.

I'm going to change out the fuel filter and check the EGR solenoid.

 

[unleadedbrew]

I haven't been able to pass for the past two years.



Only things I can think of are getting the injectors cleaned and the air pump. I hope it's not the injectors because taking the plenum and all that other stuff off to get to the injectors will be a PITA.


This is getting very frustrating. ad

Edmond, this inexpensive item is a major eliminator of hydrocarbons. Less than 50 bucks and 15 minutes to change out. I'd give it a shot. Good luck.
Gordon

 

[JonM]

You are waisting your time if your don't get the catalytic converters as hot as possible.- 2 cents worth

 

[nyernga]

This may sound crazy but make sure the clamshell is closed and they have a fan in front for airflow. Mine failed the first time and all my mechanic did was bring it in on my behalf, told them he fixed it when all he did was insist the hood be closed.


my .02

 

[black_81_vette]

WOW! is that thing rich! I dont know if a 88 tpi is set up like my 85 was but I ran no cats with a much modded engine and still passed the Il test. I would think that a vaccume leak would have to be pretty severe to cause a rich condition like that.A few things to check are. If your running a K%N filter and your car is equiped with a mass air flow meter you may have a contaminated air meter.Reason being is if the filter had too much oil on it ,it gets on the wire thats heated in the sensor and throws it out of wack.2 the cold start injector caused all kinds of havock with those set ups.I know later models added the extra fuel via the normal injectors on cold start ups.3 check the coolant sensor even if no codes are showing this can be trouble as the connector corrodes and and can cause bad readings.The coolant sensor for the computor should have a brown and yellow wire in its harness.3 check the TPS sensor those can get ruined by over zelous spraying of carb cleaner.4 Actually the best bet is find somebody with a code scanner than can track live data comming from the cars ECM this will provide you with tons of info and save you alot of $$$ chasing problems by throwing parts at it wont solve nothing unless your lucky.Well I hope I helped shed some light on this for you,good luck!!

 

[caninelver]

Edmond, I see you have an 88 like I do. I don't know what state you live in but why not check to see if your car is eligable for an antique registration so you don't have to do the emissions test. Pa requires your car be 15 yrs old and costs less than $100. Also I don't have to pay for a yearly registration. Between the registration and emission test it saves about 70-80 a year. I know every state is different but it might be worth a phone call to your DMV.Checking with an inspection mechanic might get you a wrong answer since they want the emission test money. On the last day of Sept my inspection was expiring & I had to go to 4 different inspection stations before I found one that actually knew the law. The first 3 insisted that needed the emission test. Its all about the money.

 

[Edmond]

Hi guys,

I spent a few hours today with Phil, one of the members here and he helped me out a lot. We plugged the car up to his laptop and took it for a run and came up with 2 areas that are a cause for concern:

1. MAF isn't reading out as well as it should, it's reading low.

2. TPS is kind of weak. We manually put the TB to WOT and it came out at 4.04 volts. Sitting, the reading was .51, which is in the normal range. However, stepping on the gas pedal gave me readings less than 4.

We're going to swap out MAF's and run it again to see what happens. I may also pick up his TB that only has 9K on it's life. My TB has 102K.

It's getting close, I can feel it.