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Can I use 2 GM HEI modules to replace a LX555 module?

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I'm working on a 1982 200sx with the Naps-z 8 plug engine...The ignition module is firing the intake side but not the exhaust side...Coils...wire...cap and rotor are perfect...Using the factory service manual to do a step by step troubleshooting!

I already returned the rebuilt distributor that was on the car for less than a year...Had to go through 5 so called rebuilt distributors the last time...

I was thinking if this ICM doesn't fire the exhaust side...Can I use 2 GM HEI modules to replace the stock LX555 ignitor or use just one to fire the exhaust coil? Anybody done this to the dual coil ignition system?

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I think not. Other EI dizzys have wires from the pick up coil that go to the matchbox. These wires can be used to run HEI modules but the Z dizzy has the 'matchbox' inside and the coil is built into it so nowhere to connect the HEIs.


A question: How many wires go to the Z22 dizzy? Is there a three wire harness and a separate wire with it's own connector? Like this...


Three wires with round terminals and a single light color wire with black connector half way up the other harness.



IF, yours has this other separate wire just unplug it and see if that gets the exhaust side working again. I think it will.

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Yeah, would like to know if removing that one wire fixed the problem. On the 720s the exhaust side plugs are disabled under full throttle acceleration by a vacuum switch. If your 200sx has this set up maybe the switch is stuck. Unplugging the single wire on the dizzy will disable this function and give you both plugs.

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  • 4 weeks later...

Well car is running :thumbup:

Exchanged the distributor for another one...Got spark from both intake and exhaust plugs!

I was thinking...Maybe I should have a GM HEI distributor modified with a Datsun distributor base to make a new one...After all with the correct advance curve they've been modified and used in Ford Flatheads, Ford 302, Studebaker V8 and Inline 6's and many other engines by talented machinest!

A guy in Ebay advertises and sells modified distributors for Toyotas and AMC...

Any thoughts on this...?

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  • 1 year later...

Exactly 1 year and 7 months...the damn Ignition Module went out again! Got stuck in snob town Beverly Hills...where you can hear someone blast their horn at every other intersection!

Went to O'reilly to buy a rebuilt distributor...a Cardone rebuilt unit $164...housing looked nice...but the module was definetly used!

Bought it anyway...would not get any spark and the sensor light from dash was lit. ..Returned it for a refund.

Which brand of Modules are worth the $200 plus...???

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I don't get this. The module is not visible in the 8 plug Z series distributor without removing the rotor..


What sensor light on the dash are you talking about?


The HEI module is only a switching transistor. The modules on the twin plug Z series engines have a built in reluctor and stator pick up. This is the type of module that you should need...








In California ALL Z series engines had dual spark plugs so, fill your gas tank and go check a few wrecking yards. Take a few tools and take this part out, put in you pocket and you'll still have $150 left over.


The Z engine is used in the


'80-'81 S110 200sx Z20E

'82-'83 S110 200sx Z22E

'81-'82 720 truck Z22

'83-'86 720 truck Z20

'83-'86 720 truck Z24


The '82-'83 Z22E module in the 2900sx is part # 22020-D0200 @ $300+ if they have one.


The other modules will all fire 2 coils

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Datzen Mike,


The rebuilt Cardone distributor from Oreilly which I had bought a few days ago had a used ICM...The terminals were bent , dirty, with obvious signs of being scratched where the terminal attaches to it...didn't start my car so i returned it.

The module can be seen quite easily with the distributor cap off...which helps conduct the test table on EL-26 and EL-27 from the FSM.

On my '82 200sx dash cluster...it has a factory sensor light that seems to go on each time the ICM is not functioning...if you have the FSM look under EL-53.

The photo of the module you posted is for the '79 to '81 NapsZ models...mine has the 4 pin model.

I didn't want to start a new thread...so I piggy backed on my posting from last year...Did this cause the HEI confusion?

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