High energy ignition, also known as H.E.I., is an electronic
ignition system
An ignition system generates a spark or heats an electrode to a high temperature to ignite a fuel-air mixture in spark ignition internal combustion engines, oil-fired and gas-fired boilers, rocket engines, etc. The widest application for spark i ...
designed by the
Delco-Remy Division of
General Motors. It was used on all GM vehicles, at least in the North American market, from 1975 through the mid-1980s. There were many design variations over the years, and provisions for computer controls were added for some applications starting in the late 1970s. A predecessor system called "Unitized Ignition" was optional on 1972 and 1973
Pontiac Pontiac may refer to:
*Pontiac (automobile), a car brand
*Pontiac (Ottawa leader) ( – 1769), a Native American war chief
Places and jurisdictions Canada
*Pontiac, Quebec, a municipality
** Apostolic Vicariate of Pontiac, now the Roman Catholic D ...
s.
Most—but not all—HEI systems have the
ignition coil
An ignition coil (also called a spark coil) is an induction coil in an automobile's ignition system that transforms the battery's voltage to the thousands of volts needed to create an electric spark in the spark plugs to ignite the fuel. So ...
mounted in the
distributor
A distributor is an enclosed rotating switch used in spark-ignition internal combustion engines that have mechanically timed ignition. The distributor's main function is to route high voltage current from the ignition coil to the spark plug ...
cap. A control module and magnetic pickup are mounted in the distributor, in place of a conventional ignition system's
breaker points and
condenser.
Control modules
There are four basic types of HEI control modules: four-, five-, seven-, and eight-pin. The four-pin module was used on
carbureted
A carburetor (also spelled carburettor) is a device used by an internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the venturi tube in the main meteri ...
engines and uses conventional mechanical timing controls (vacuum and centrifugal
advance
Advance commonly refers to:
*Advance, an offensive push in sports, games, thoughts, military combat, or sexual or romantic pursuits
*Advance payment for goods or services
*Advance against royalties, a payment to be offset against future royalty pa ...
mechanisms). The five-pin module was introduced in 1978 and was an early attempt at electronic timing control; it contains a provision for connecting a
knock sensor. The seven- and eight-pin modules are used on early
computer-controlled engines in conjunction with fixed-timing distributors, as the computer controls the ignition timing.
Upgrading
HEI distributors are a popular swap on older GM cars originally equipped with points and condenser type ignition systems.{{Citation needed, date=March 2020 The HEI system produces a more powerful spark, which allows for a wider
spark plug gap for surer ignition of a fuel/air mix that may not be optimal. The HEI setup has also become a popular swap into non-GM vehicles.
References
External links
* http://delcoremyhistory.com/history.htm
* http://www.pontiacpower.org/HEI.pdf
* http://delcoremyhistory.com/history.htm
* https://saemobilus.sae.org/content/750346/#abstract
Ignition systems