86 Ignition Control Wiring.... What goes Where ?

[Yinzer]

 4 Prong..... E, C, B and I 

 

 3 Prong.... E, B and I 

 

What do the letters correspond with ?

 

 

 

[datzenmike]

One is power from the ignition. Two go to the negative side of the coils and the extra one is the signal to turn the exhaust side coil off under load. This is a white or gray wire with it's own plastic plug external to the three wire harness on the distributor. When grounded the exhaust side coil works. A vacuum switch senses low intake vacuum (heavy load) and removes the ground and the module shuts off the exhaust side coil. Unplugging it will defeat this and keep the exhaust side firing at all times.

 

 

 

Sorry no answer but it's a good question.

[Yinzer]

17 hours ago, datzenmike said:

One is power from the ignition. Two go to the negative side of the coils and the extra one is the signal to turn the exhaust side coil off under load. This is a white or gray wire with it's own plastic plug external to the three wire harness on the distributor. When grounded the exhaust side coil works. A vacuum switch senses low intake vacuum (heavy load) and removes the ground and the module shuts off the exhaust side coil. Unplugging it will defeat this and keep the exhaust side firing at all times.

 

 

 

Sorry no answer but it's a good question.

So what would happen if the Exhaust side is firing all the time ? Would it perhaps overheat the Module ?? 

 

 Which Vacuum Switch removes the Ground ? My truck has all the Emission stuff removed.

 

 What do the Letters B and C mean on the 4 Prong ?

 

What is different than the 3 Prong from the 4 Prong ? I know the 3 Prong goes to Early 80s Z24 and 4 Prong from there on.

[datzenmike]

They all fire all the time and together normally. Apparently under heavy load the engine makes excessive noise* so Nissan changed the distributor to 4 wires and a vacuum switch to sense the load condition. The exhaust side is deactivated while under extreme loads.

 

* This could be the two flame fronts colliding inside the combustion chamber. Might make clacking sound like a diesel? I had a Z24 in my 620 and it had a three wire distributor and I never noticed any extra noise under load.

 

If that separate wire is unplugged or the vacuum switch removed then the exhaust side CAN'T be shut off.

 

I believe the four terminal distributor began with the introduction of the Z24 engine in Nov. '82 the start of the '83 model year. The '81-'82 Z22 had the three wire distributor.

 

I couldn't guess which wires go to which terminals

[A guy named Rick]

On 5/16/2023 at 6:04 AM, datzenmike said:

They all fire all the time and together normally. Apparently under heavy load the engine makes excessive noise* so Nissan changed the distributor to 4 wires and a vacuum switch to sense the load condition. The exhaust side is deactivated while under extreme loads.

 

* This could be the two flame fronts colliding inside the combustion chamber. Might make clacking sound like a diesel? I had a Z24 in my 620 and it had a three wire distributor and I never noticed any extra noise under load.

 

If that separate wire is unplugged or the vacuum switch removed then the exhaust side CAN'T be shut off.

 

I believe the four terminal distributor began with the introduction of the Z24 engine in Nov. '82 the start of the '83 model year. The '81-'82 Z22 had the three wire distributor.

 

I couldn't guess which wires go to which terminals

I'm curious, I see in the FSM about vacuum switch C and I have a California model Z24 but I don't have vac switch C. And I have the 4 terminals. Does A or B control it also in addition to the fuel cutoff? 

[Yinzer]

On 5/17/2023 at 9:20 AM, A guy named Rick said:

I'm curious, I see in the FSM about vacuum switch C and I have a California model Z24 but I don't have vac switch C. And I have the 4 terminals. Does A or B control it also in addition to the fuel cutoff? 

 Anyone know ?