reintr0ducing Posted December 2, 2016 Share Posted December 2, 2016 Trying to figure out where I'm having problems on swapping my '76 280 (automatic) to SU's. I've been searching for the last couple of hours... Disconnected all the efi harness connectors on the drivers side (injectors, afm, cold start, water temp sensors to cold start) but left the ecu and the other half of the harness untouched for now, unbolted the manifold and swapped on my spare round top su's. Changed out the pump for a low pressure and a regulator. Turned key and click. No power to fuel pump and no crank from the starter. My friend plugs in the big connector under the (disconnected) AFM and the fuel pump powers on with the key in the on position but still no crank. At this point it's late so we call it a night for dinner and beer. Sitting in my favorite chair armed with my iPad and a six pack of Guinness, I learned most people wire the fuel pump to turn on with either a switch or the key in the on position (which will still pump in the event of an accident, I know). Will work on that next time I work on the car. What I've been trying to search for is why the starter won't kick over. Electricity is black magic and wizardry to me but my friend is helping me with that end. Should we be looking into the neutral safety switch being that this is an auto? Jumper wire to the starter? Also, anything else I'm missing in the whole swap to carbs process? Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted December 2, 2016 Share Posted December 2, 2016 You can can hardwire the start with a relay also. Most people do that anyway to save the steering stalk wiring anyway. I think the issue might be something to do with your auto trans start feature. I don't know anything about what conditions need to be met to start an auto trans, but I'm sure it has a park feature. It could be from how it's wired. Quote Link to comment Share on other sites More sharing options...
KevvinG Posted December 2, 2016 Share Posted December 2, 2016 (edited) I believe your non cranking issues is stemming from some sort of neutral/park safety switch being that your car is an auto. Unfortunately I don't have any experience in that regard. However the fuel pump situation I can definitely help with. The wiring to the fuel pump goes as such: The fuel pump is ON if the key is in the START position (cranking), the fuel pump is ON if the key is in the ON position AND there is air being pulled through the AFM (Engine is running normally), the fuel pump is OFF if the key is in the ON position AND there is no air being pulled through the afm (Engine stall or accident). When I converted my '77 280Z to triple webers I found a wiring diagram (that's lost to me now but if I find it again I'll post it up) that showed that if you jumper the two rightmost pins on the afm then the pump will always run when the key is put into the ON position. This doesn't give you any safety in the event of a crash but will help get your car running for now. I've been thinking of using a vacuum switch to trigger that fuel pump connection using the brake booster vacuum but I haven't gotten around to it yet. Edited December 2, 2016 by KevvinG Quote Link to comment Share on other sites More sharing options...
Miles Posted December 2, 2016 Share Posted December 2, 2016 I was just researching this. There may be an answer here: https://www.google.com/search?q=convert+280z+fuel+injection+to+SU+carbs&ie=utf-8&oe=utf-8 Quote Link to comment Share on other sites More sharing options...
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