High energy ignition

High energy ignition, also known as H.E.I., is an electronic ignition system 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.^[vague] 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 Pontiacs.^{[citation needed]}

Most—but not all—HEI systems have the ignition coil mounted in the distributor 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 engines and uses conventional mechanical timing controls (vacuum and centrifugal advance mechanisms).^{[citation needed]} 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.^{[citation needed]} 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]} 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

This page was last edited on 6 April 2021, at 02:14