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New to the forums. Looking for insight on what to do.


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Hello all. I am the owner of a 1983 Datsun 280zx. Ive owned if for a little while but its been giving me many problems. It alternates in between the states of "runs for 3-4 seconds and then dies" or 'doesn't fire up at all". The efi system is petty complicated and Ive replaced many things like wires and the starter and more things of the sort. Ive tried real hard but I can't get it to run on E.F.I. .......... Ive been thinking extremely hard about switching to carbs but at the same time I want a bit of power out of this thing while I'm making the switch and buying parts. still deciding on whether to

- stay Na, and fix the EFI and just get ITB's

- stay NA, get triple Webers, cam and exhaust. 

- draw through turbocharging

- blow through turbocharging

- EFI turbocharging with mega squirt, T3, all turbo parts needed to tune. 


mainly looking for insight, past experiences or any tips or pricing on any of the sort. If needed, my expectations as for power for an NA are around 235hp, and the turbo is about 350hp.

Budget is 2.5-3.5k 



Edited by Zellthetunerr
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No offense intended but the early EFI systems are actually pretty simple.  If you plan to be a real tuner it's a good system to learn on.  Download the service manual and the EFI book and do the appropriate tests.  If it starts but dies it seems like a fuel pump or pump control problem.







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Ok, I already have the manual downloaded and I did the tests a while back. What I found out is that there’s no continuity from the yellow wire in the harness from ignition switch to the starter. I can’t find where the break is though. I had an idea and I just ran a custom wire from ignition switch to the starter, then I just also attached one to the yellow wire so that the cold start valve would fire. It did, but the car dies after a few seconds of running. And I just did the same thing but the csv doesn’t fire no mo. So I need to find the problem....

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Old wiring is a pain in the ass. Look first at all connectors for corrosion, the wires are probably OK if not modified. Do not assume anything is getting signal, voltage, ground as it should be. Always start with the simple stuff, then work toward the more difficult, like point to point continuity. I once had a fuse that looked fine, had continuity, but would not take any current. Lesson learned, verify the simple stuff first and I mean verify. Someone posted some good detail on this recently.


The Bosch L-jetronic is a very simple system. Not many inputs or outputs. When everything is working as it should, it is bullet proof and fairly easy to troubleshoot. It can even be adjusted slightly for mild modifications. If you can troubleshoot components per the factory manual, you are way ahead already. 


As you can tell I am a big fan of these original systems. I played with them for years. One of the favorite Zs I have owned was a 80ZX with big throttle body, ported 76 intake, mild pocket porting on the head, 6-2 headers with 3" exhaust on stock efi. Otherwise stock. Something about the sound, rear end squat, and flat torque curve just worked right.  But I will also never forget chasing that damn fuse problem for 2 weeks. Or the time the heater hose had leaked on a connector and corroded it and I did point to point checks for 2 weeks, and the time.....old cars are tough.

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