Failed emmissions testing


Old 10-17-07, 05:52 PM
Thread Starter
Join Date: Oct 2007
Posts: 2
Received 0 Votes on 0 Posts
Failed emmissions testing

1991 Toyota Celica GT
Engine 5S-FE
Auto Trans.
Mileage: Car 158,000 Engine: unknown junk yard replacement.
Problem: Will mot pass Maryland emissions test.
Hydrocarbons: State standard- 1.00GPM Inspection result- 1.97GPM Fail
Carbon Monoxide: State standard- 20.00 GPM Inspection result- 71.41 GPM Fail
Oxides of Nitrogen: State standard- 2.2 GPM Inspection result- .636GPM Pass
Current gas mileage mostly highway driving is 22.2 MPG
The engine starts and runs well and occasionally is a little jerky when not under an acceleration load. I replaced the engine in March 2007 with all new tune up parts at that time and have put 7,000 miles on it since then.
After failing the emissions test I took it to a shop listed in the brochure given to me by the state testing office. The shop found a vacuum hose that had a hole and replaced it. They also checked the timing and scoped the engine. Next they checked compression and cylinder leakage with good results. They checked the emissions at 900 RPM and the results are; HC 214 limit 220, CO 1.18 limit 1.20, CO2 17.0. They told me to use 40wt oil and run it through the state dynamometer which I did. The results are listed at the beginning of this statement way above. I then decided to look into this myself a bit so I pulled the spark plugs and found all four of them with thick black carbon, much the same as the end of the tail pipe powdery carbon. The next thought was that maybe the cold weather injector was stuck or being told to spray while the engine was hot so I removed the injector, plugged the manifold hole and started the hot engine to see if any spray was there, none was observed. Since I had the old engine I replaced the injector anyhow but no change in fuel mileage was observed. That brings me here any ideas?
Sponsored Links
Old 10-18-07, 06:40 AM
Join Date: Dec 2001
Posts: 2,538
Received 0 Votes on 0 Posts
start off by checking to see if there is any codes in the computer might check out the link below on how to retrieve codes.
the car is running rich and its probably due to a sensor but hopefully it will have a code stored in the computer that will give you some place to start if its been running rich you will probably want to check the o2 sensor as its probably looking similiar to your spark plugs and gas fouled and not reading very good. when you think you have the problem fixed you should probably put in a new set of plugs and change the oil prior to having it retested.
Old 10-20-07, 02:38 PM
Thread Starter
Join Date: Oct 2007
Posts: 2
Received 0 Votes on 0 Posts
Thank you for the help accessing the on board computer. However it flashed normal and contained no codes. With no other ideas I have adjusted the throtle positioning sensor to cause the computer to think the the throtle is less open and will run a tank of gas to see if the mileage inproves.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes
Ask a Question
Question Title: