Contents

Fix it!
Air Care News
Emissions Repair Guide
Tech training
Enforcement news
Get registered
Top techs
High altitude study
Repair site index
Repair links
About Envirotest
Repair Bay home
Air Care CO Home

High Altitude Study
Part 1
 
A Study of Six Difficult to Repair I/M 240 Emission Failures

Conducted by Chris Chesney, Diagnostic Technician Education Consultants (DTEC), 1997-98 

(This website contains only excerpts from the study. For the full study, contact the Colorado Department of Public Health and Environment, Air Pollution Control Division, 303-692-3126.

Project Profile

The primary focus of the High Altitude Study is the verification of effective diagnostic strategies and the development of cirrocumuli to enable technicians to successfully repair the identified problem vehicles. Using the data supplied by CDPHE and Envirotest, candidates were identified and recruited for verification testing.

The subject vehicles were identified by CDPHE. The primary selection criteria were multiple I/M 240 failure and difficulty of successful repair. The selected vehicles are;

1. 1984 – 1985 Honda Accord 1.8L Low Altitude Certified.
2. 1986 – 1989 Hyundai Excel 1.5L, 1985 – 1989 Dodge/Plymouth Colt 1.5L;
   1985 – 1989 Mitsubishi Mirage 1.5L, 1987 – 1989 Mitsubishi Precis 1.5L.
3. 1983 – 1987 Toyota Tercel 1.5L.
4. 1983 – 1985 Ford Bronco, Club Wagon, F150, F250 4.9L.
5. 1984 – 1985 Chevrolet/GMC S10/15 T10/15 2.8L.
6. 1982 – 1986 Chevrolet/GMC LDGT 5.0L/5.7L.

These vehicles exhibit a high failure rate and tend to be difficult to repair. It should be noted that vehicles one, two, and three are feedback carbureted, Asian manufactured vehicles. Four is a domestic feedback light duty truck, and five and six are domestic light duty non-feedback trucks.

More Info

 Part 1: High Altitude Project Profile
 Part 2: Project Methodology
 Part 3: 1982-86 Chevrolet LDGT 5.0/5.7L; Non-Feedback Quadrajet
 Part 4: 1983-85 Ford LDGT 4.9L; EEC-IV Feedback Carburetor
 Part 5: 1984-85 GM/Jeep LDGT 2.8L; Non-Feedback Varijet
 Part 6: 1984-85 Low Altitude Honda Accord; Carburetor Feedback System
 Part 7: 1985-89 Imports: Hyundai, Mitsubishi, Plymouth; Feedback Carburetor System
 Part 8: 1983-87 Toyota Tercel; Computer Controlled Emissions

Chris Chesney is the owner of Diagnostic Technician Education Consultants (DTEC), 5497 S. Danube Way, Aurora, CO 80015.  He can be reached at 720-870-6761 or via email at chesneydtec@cs.com. Chris has trained hundreds of technicians in I/M 240 diagnosis and repair.