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Injectors not firing, no power. Bad ecu?


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I've recently been trying to get my 83 5 speed non turbo car on the road and am having problems getting it to start.

The car ran fine then I took the ign module off, dropped and boiled the tank out and ran new lines and cleaned the throttle body and all connections/grounds/relay prongs. Then it ran but very very rough and would die with any throttle. I then received a new ignition module and after putting it in am having the problems I get now.


Fuel lines etc are connected properly

It's got new plugs

Afm is good

Throttle valve switch is good

Coil is good

Dizzy is good

Spark is strong at plugs

New ignition module because my old one caused the car to die when hot

Fuel pump is good

Gas tank, sender etc is good

Fuel makes it to and through the rail easily

Fuel pressure is good

All grounds and connections are triple checked good


I tried all the multimeter tests I could from the FSM in the EFEC section starting around 90ish. I tried hooking up a light to the injector plug and got no light. The injectors do not fire when car is turned over.

Car runs fine with starting fluid

Car has been sitting for 4-5 years

I took apart the sheathing on the wiring harness and all wiring from ECU to injectors or anything else is solid and good. I'm simply getting nothing from injectors and I don't know why.


I took the ECU out and opened it up, there were several (4-5) resistor type items (not resistors spherical in shape with a half white half purple colour) that had what looked like puffy corrosion on either side of the middle section. I cleaned them off and nothing changed. Could my ECU be the problem? I'm trying everything before I buy a new one because they're expensive.

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All of those "good"s just mean maybe.  Why didn't you write the numbers down?


The ECU grounds the injectors when it sees action on a certain pin at the ECU, which is connected to the coil's negative terminal.  Which is also connected to the ignition module.  Maybe you disconnected a wire by accident.  The module you replaced is the matchbox on the side of the distributor, right?


And you said no power, implying at the injectors, but didn't say that you actually tested for power at the injector plugs.


I would check for power at the injector connections, and confirm that the trigger wire to the ECU, the one connected to coil -, is intact.  Unfortunately, there aren't any good wiring diagrams for 1983 that I know of.  It's a difficult car to work on.


1982 might be the same.  Worth a shot.  Looks like Pin 18 at the ECU should be connected to coil -.  http://xenonzcar.com/s130/images/wiring/1982%20Datsun%20280ZX%20non%20turbo.pdf

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I'll check connections again tomorrow, the module I replaced is the black matchbox on the side of the distributor yes. I connected a light to the injector plug while turning the engine over with everything connected and got no light at the injector connector meaning no pulse/power. However when I tested the pins in the 35 pin plug running to the ECU I got battery voltage at pins 2,3,5,6,7,8 which means power for the injectors is reaching the computer and not leaving it.

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The ECU just reacts to what Pin 18 does.  When the coil discharges, the voltage pulse on Pin 18 makes the ECU ground the injector circuits.  So if you're getting spark and Pin 18 is connected to the coil negative terminal, something's not working right in the ECU.

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The connection leading to - side of coil was unplugged meaning no signal to ecu and no injectors firing! Ive been banging my head on this thing for weeks :/ It's running now but I'm back to old problems. It's got hesitation in throttle and an occasional backfire from the intake around the afm. When I give it throttle it revs up then when revving down around 1500-2000 rpm the revs hang up for a second and it makes a sucking sound like a vacuum cleaner.

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