Dual ignition?

Clintman · Aug 11th, 2003, 08:20 PM

On my 84 720 pick-up i have the Z24 engine with the dual sparkplugs per cylinder. I was wondering when does the second coil come on because mine isn't every going hot. The leads that go to it are always cold. Also i have been tring the figure the wirng out to the coils but the Haynes manual I have doesn't show the correct wire colors. I have brown, white/blue, red and a black/white wires. I currently have the brown wire hooked to i gues the exghuast coil + and the white/blue wire hooked to the negative. But the other two wires seem to be dead. I was wondering if anyone might have a wiring diagram or just tell me what wires go where because i am relly stumped.

nissannut · Aug 14th, 2003, 10:35 AM

Both coils are always active. The ECU turns off one side (i think the exhaust) under heavy or something. i have it in the book.

I have some factory wiring diagrams. Do you want me to scan and email or ??

Check the fuse box. Each coil has its own fuse. I have owned 3 85 720 for over 10years.

Dec 26th, 2003, 06:44 PM

Quote:

Originally Posted by nissannut

Both coils are always active. The ECU turns off one side (i think the exhaust) under heavy or something. i have it in the book.

I have some factory wiring diagrams. Do you want me to scan and email or ??

Check the fuse box. Each coil has its own fuse. I have owned 3 85 720 for over 10years.

where are the fuses you refer to for each coil??? my 1986 z24 p-up just quit. changed cap wires and rotor, with no help. only the front coil is firing. could it be the ecu?? is there any way to check it? I had another 86 many yrs. ago that the only problem I had was the ecu went out, but I can't remember why or the systems

nissannut · Dec 26th, 2003, 11:01 PM

Quote:

Originally Posted by firebrillo

where are the fuses you refer to for each coil??? my 1986 z24 p-up just quit. changed cap wires and rotor, with no help. only the front coil is firing. could it be the ecu?? is there any way to check it? I had another 86 many yrs. ago that the only problem I had was the ecu went out, but I can't remember why or the systems

You have a 86.5 z24i fuel injected right?

86 is still a 720.

The fuse panel has 2 fuses one for each coil. The regular fuse panel to the left of the steering wheel above the clutch pedal.

Are you sure its a "no spark issue"? Check the ECU fusible links at the battery. The ECU do not get power from the fuse panel, but directly from the battery via fusible links. Basically the ECU is always "on".

I have never had one fail. I have a FSM (factory service manual) for 86 and 88 but there is a 86.5 I do not have. 87 and 86.5s are identical. The ecu changed in 88.

If you have spark at either side plug 1, the computer is good. Check for fuel...

The engine will run with either coils but both fire 99% of the time.

Let me know if you need pics from FSM.

Good luck