ASE H1 CNG Engines (Transit Bus) Practice Questions - ASE H1 - Compressed Natural Gas (CNG) Engines (Transit Bus) Certification Exam - ASE H1 CNG Engines (Transit Bus) Practice Questions - ASE H1 - Compressed Natural Gas (CNG) Engines (Transit Bus) Certification Exam

Question 1

A transit bus with a Cummins L9N CNG engine cranks but will not start. There is no spark on any cylinder. Which check should the technician perform FIRST?

Replace all spark plugs and ignition coils Verify the crankshaft and camshaft position sensor signals and engine speed during cranking Drain and refill the CNG fuel tanks Replace the three-way catalytic converter

Correct Answer:

Verify the crankshaft and camshaft position sensor signals and engine speed during cranking

Question 2

Technician A says a stoichiometric CNG transit-bus engine runs at an air-fuel ratio near lambda 1.0 so a three-way catalyst can work. Technician B says these engines always run lean-burn for emissions. Who is correct?

Technician B only Technician A only Both A and B Neither A nor B

Correct Answer:

Technician A only

Question 3

A CNG transit bus has a rough idle and a stored cylinder 4 misfire code. Compression and ignition on cylinder 4 test normal. What is the MOST likely remaining cause?

A leaking radiator cap A failed engine coolant temperature sensor A worn serpentine belt A faulty or clogged cylinder 4 gas injector delivering incorrect fuel quantity

Correct Answer:

A faulty or clogged cylinder 4 gas injector delivering incorrect fuel quantity

Question 4

During a cylinder balance test on a CNG transit-bus engine, disabling cylinder 2 produces almost no change in engine rpm. This indicates that cylinder 2:

Is the strongest cylinder in the engine Was already contributing little power and is the weak cylinder Has excessive compression Is operating with an overly rich mixture

Correct Answer:

Was already contributing little power and is the weak cylinder

Question 5

A methane gas detector mounted in the engine compartment of a CNG transit bus repeatedly alarms with no visible leak. Which characteristic of methane should the technician keep in mind during the search?

Methane has a strong natural odor that pinpoints leaks Methane is heavier than air and pools on the floor Methane is lighter than air and collects at the highest points of an enclosure Methane is non-flammable below 50 percent concentration

Correct Answer:

Methane is lighter than air and collects at the highest points of an enclosure

Exam overview

About this Exam

Prepare with the ASE H1 CNG Engines (Transit Bus) Practice Questions - ASE H1 - Compressed Natural Gas (CNG) Engines (Transit Bus) Certification Exam practice quiz. This question bank includes 100 questions covering engine, transit-bus, technician, says, and cylinder. Use it to review important concepts, identify knowledge gaps, and build confidence for the related exam, course, or assessment.

More details

Additional Information

ASE H1 CNG Engines (Transit Bus) Practice Questions - ASE H1 - Compressed Natural Gas (CNG) Engines (Transit Bus) Certification Exam

This practice set contains 100 questions from the matching question bank and focuses on engine, transit-bus, technician, says, and cylinder. Work through each question carefully, review the provided solutions, and revisit topics that need more study before your next attempt.

This is an independent study resource intended for practice and review; it is not an official examination or an endorsement by any organization named in the title.

Quiz information

Frequently Asked Questions

The complete question count is available after full access is unlocked.

No fixed duration is currently configured for this quiz.

Question explanations are included where they are available in the quiz content, helping you review the reasoning after answering.

Yes. You can retake the practice test again as you continue studying during your available access period.

After your access is confirmed, you can continue into the complete practice exam from this quiz flow.

Unless explicitly stated otherwise, this page provides independent practice material for study and exam preparation and is not the official examination itself.

Correct Answer:

Correct Answer:

Correct Answer:

Correct Answer:

Correct Answer:

About this Exam

Additional Information

ASE H1 CNG Engines (Transit Bus) Practice Questions - ASE H1 - Compressed Natural Gas (CNG) Engines (Transit Bus) Certification Exam

Frequently Asked Questions

Related Questions

2026 FFM Agent Broker Certification Practice Exam

3CX Academy Advanced Certification Practice Exam

3CX Academy Basic Certification Practice Exam

3CX Intermediate Certification Practice Exam

Ultimate Study Guide for the Argus Certification Practice Test

Arizona Caregiver Certification Practice Exam