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Brandn3w

Troubleshooting issues: 280zxt fsm?

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I recently purchased a 1982 280zxt, the cars been sitting for a year prior to my purchase.  Tried to turn her over, but nothing. No spark no love, so i tried having a friend work on my harness, i switch out my ignitor for a more updated control module.  Receiving power to my coil, everything else checks out like my fusible links, ecu lights up.  I replaced the pickup within the distributor as well.  Sorry im all over the place, but i checked yhe fsm. Saw the trouble shooting for the dizzy but it doesnt show a four prong plug like my dizzy but instead illustrates a 3 prong. Also having a hard time figuring out which wire goes where. Please help because ive been dealing with this issue, im new to the project life but im really eager to learn.     

 

(Pages EL. 28- 29)el.pdf

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If you have a turbo model you should be on page 32.  It's called a Crank Angle Sensor, CAS.  You probably switched for something like the Pathfinder power transistor?

 

The 280ZX manuals are hard to work with.  They don't flow very well and Nissan put troubleshooting and wiring diagrams in odd places.  You might have better luck in the Engine Fuel and Emissions Control, EFEC, chapter.  The ECCS uses the CAS to control timing and fire the injectors.  I'm pretty sure I've seen CAS troubleshooting in that chapter.

 

cgsheen knows a bunch about the 280ZX ECCS system.  Search his name and CAS and you'll find some stuff.  He's around occasionally.  @cgsheen Good luck.

 

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21 hours ago, Brandn3w said:

A - i switch out my ignitor for a more updated control module. 

B - ecu lights up. 

C - I replaced the pickup within the distributor as well. 

D - four prong plug like my dizzy but instead illustrates a 3 prong. Also having a hard time figuring out which wire goes where.      

 

(Pages EL. 28- 29)el.pdf

 

A - What are you using for an Ignitor?  (Early on in my L28ET life I read lots of stories about the stock Ignitor going bad - but that has never been my experience.  I actually find them very reliable when wired correctly.)

 

B - The ECU LED is not a "power on" indicator.  Read the ECCS section of the FSM.  Proper operation is:  LED lights at Ignition ON and goes OFF when the ECU "senses" engine rotation (gets the proper signal from the CAS).  If it's not turning off when cranking, there's a CAS or wiring fault.  (everything in the ECCS system starts with the CAS.  Once the ECU has verified engine rotation and position, it can start to send the spark signal.  The ECU signal to the ignitor is hard to verify without a scope. 

 

C - You replaced the optical module in the distributor?  More info may be needed...

 

D - Search - there are numerous posts and pictures of the 4-pin plug for the CAS and it's wiring. Do you have the stock ECCS wiring harness?  Any modifications to the harness?

 

Like NewZed said above:  Make sure you stay in the ECCS sections of the FSM.  The FSM has information about both the EFI (N/A) and ECCS (Turbo) engines so don't get them confused.  I actually find the 1982 FSM easiest to follow, but the same basic information is in all the Turbo sections 1981-1983.  

 

(I have found with my own engine and multiple others that most of the problems with these engines are with wiring and connectors then sensors.  If your experience is like most others, you'll fight with the stock ECCS harness and components until you decide to replace it with a different engine management system or at a minimum replacing/building a new engine harness...  I wish I had all the hours back that I spent with the stock ECU and harness - BUT I did learn a lot on that journey.)

 

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One way that people test the CAS is to pull the distributor (the CAS is inside, the disc with the holes), turn the key on, and spin the distributor by hand.  If the CAS is working and the ECCS computer is getting a good CAS signal the injectors will open and click as it spins.  If you don't get injector opening then there's a CAS and/or computer problem.  If you get injector opening but no spark, you probably have an ignitor, coil, or distributor problem.

 

Also, if you decide to probe the CAS with a meter, you have to do it from the back of the plug while it's connected.  With a good meter sometimes you can see the CAS signal. I think that cg has posted on that also.

 

Here's a Google search with some good reading:

 

https://www.google.com/search?source=hp&ei=UAJeXKWcFNrA0PEPjPyTyA0&q=site%3Ahybridz.org+cgsheen+cas&btnK=Google+Search&oq=site%3Ahybridz.org+cgsheen+cas&gs_l=psy-ab.3...1162.8970..10635...0.0..0.62.1027.28......0....1..gws-wiz.....0..0j0i131j0i10.QSMwtW6q4j4

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@cgsheen thanks for your response

 

A ) my stock ignitor was rusted through. So ended up switch to this https://www.google.com/imgres?imgurl=https://images.oreillyauto.com/parts/img/large/acc/35361.jpg&imgrefurl=https://www.oreillyauto.com/detail/b/accel-2714/ignition---tune-up-16776/ignition-module-control-unit-ignitor-12521/e281cd9fff15/accel-4-terminal-ignition-control-module/35361/2473595&h=431&w=500&tbnid=xJYCjPCEV4RgGM&tbnh=208&tbnw=242&usg=AI4_-kSJxcn2QLQg9crvSYkvkk-fEN4Ucw&vet=1&docid=IGxzYjBAh5Ll3M

B ) oh okay well once i get off of duty ill try verifying that the ECU light turns off when cranking and ill thoroughly read the ECCS in my FSM copy.

 

C ) So as far as the pickup goes, my crew and I assumed it would be best to replace it for "better connection."

 

D ) This might be dumb to say or ask, but when you say wiring harness you mean engine harness right? If so then yes its stock, minus having a friend clean it up by providing better grounds and performance wires. Previous condition was sketchy.

 

I know i have a lot of learning to do, and have a ways to go.  I'll make sure to stay in the ECCS section of the FSM. An glad to know that the basic information goes across the board. Now what would you recommend when it comes to switching out my engine management system?

Edited by Brandn3w

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LOL, ya - I was talking about the engine harness - but that applies to most of the electrical in a Z or ZX as well...  In the Turbo car it's more appropriately called the ECCS harness.  Just so we're all talking about the same thing. 

 

The "pickup" inside the distributor is an LED "optical module" that "reads" the slits on that  thin stainless steel disc - many refer to it as a "chopper wheel".  That entire unit is the Crank Angle Sensor.

 

And you're using a GM HEI equivalent ignition module which is a common replacement for the stock ignitor.

 

No spark out of the coil at all?  But you can get a coil spark manually? 

 

Start at the beginning and follow the path.  The troubleshooting steps are laid out in the FSM.  Don't get confused by the sections for Nissan Techs using the Nissan E.C.C.S. Analyzer.  The same tests (almost) can be done without it and you'll find them in later pages of the manual.

 

Please!  DON'T open your AFM...  It'll be the last thing you'll ever want to fiddle with and then only do it after you understand ALL ABOUT Bosch L-Jetronic fuel injection.

 

"Now what would you recommend when it comes to switching out my engine management system?"

That's a tough question to answer - I don't know what you want to do with your car...  The L28ET is a pretty basic early fuel injection engine.  Most modern engine management systems are kinda overkill and may not be necessary at all if you keep the engine stock.  If you modify the engine much from stock, you'll definitely need a way to tune it.  Start reading here, you'll find many that have switched to Megasquirt but that's not the only thing you can do.  There are a number of engine management systems that could be used That being said, on mine I've used the absolutely stock ECCS, I've used an Infiniti M30 (F31 - VG30E V6 engine) ECU "chipped" with a Nistune daughterboard and a custom ECCS harness, and I'm currently using Megasquirt 3X (full sequential fuel and spark using Ford COP coils) with another custom engine harness.  I'm a wiring guy so I build my own harnesses.

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