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What is a normal Distributorless Ignition System - multiple choice test?

  1. Technician A says that when the coil fires on a DIS system, it actually fires two spark plugs at the same time. Technician B says that when the DIS system fires, both cylinders are on the compression stroke at the same time. Who is right? a. A only b. B only c. both A and B d. neither A nor B answer A

  1. Technician A says that a DIS system uses one coil for each spark plug. Technician B says that some systems use one coil for every two spark plugs. Who is correct? a. A only b. B only c. both A and B d. neither A nor B answer B

Why B on question 2? Most cars use one coil per plug. Question 1 is also confusing - this would mean that on DIS, no two cylinder is at TDC at a given time? And why do some DIS coils have three wire? Thanks Ric

Reply to
Ricky Spartacus
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Don't know about most cars since one person would have a hard time doing the statistics, Most DIS systems are one coil for two sparkplugs (cylinders). Technically, many versions fall under the generic term DIS ignition, hell, anything without a distributor can be considered to be DIS, correct? Coil on Plug, Coil near plug, IDI, etc.

Actually, it would mean that there usually *are* two cylinders at TDC at the same time. The most common exception would be harley-Davidson V-twin motorcycles due to their unique cylinder timing, but most common V, inline and flat engines have two cylinders at TDC at the same time, almost a certcinty if the engine has an even number of cylinders.

Three secondary wires??? Dunno, haven't seen one. Can you cite an example?

Reply to
Neil Nelson

"A" is true for a waste spark type system. Usually one plug is on the compression stroke, the other on an exhaust stroke. See

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This does not apply to DIS systems that have one coil per plug.

No, many DIS systems use 1 coil per two plugs (see answer to 1 above).

Most four stroke engines with an even number of cylinders are arranged so that there is always one cylinder on the compression stroke and one cylinder on the exhaust stroke at the same time. When you fire the plugs on these cylinders together, the spark in the cylinder on the compression stroke ignites the mixture while the plug that fires in the cylinder on the exhaust stroke does nothing. The mixture in that cylinder is already burned.

All coils have at least three wires - primary voltage, primary / secondary ground, secondary voltage (high voltage spark plug type wire). Coils used in waste spark ignition systems have four wires - primary voltage, primary ground, positive secondary voltage ("+" high voltage spark plug type wire), negative secondary voltage ("-" high voltage spark plug type wire). Or did you mean something else? I suppose it would be possible for a coil to have four wires - primary voltage, primary ground, secondary voltage (high voltage spark plug type wire), secondary ground.

Ed

Reply to
C. E. White

Go here and read about GM's:

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Reply to
 Paul 

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. This does not apply to DIS systems that have one coil per plug.>

Makes a lot of sense now, everybody. The type referring to is the single coil per cylinder top a plug mount. Found on 2003 Hondas and Toyotas. I was baffled by the three ordinary wires from the top of it. Was wondering how to check for sparks on these kinds or what transistors drive them?

Reply to
Ricky Spartacus

And 1998 Chryslers and Dodges.... and lots of others too.

Reply to
Steve

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