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HELPP!! l28et in s30 Swap


voong413

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I've just doubled checked and cleaned all the connectors on the plug and injectors,I tired cranking it again with no luck. I don't have a fuel pressure gauge so I haven't determine if the injectors are getting a sufficient amount of pressure, but I did just realized I was using a 81 wiring harness that requires a dropping resistor for the injectors, running on a 83 ecu that gets direct power from the fusible link. I tried unplugging the fusible link, but then the injector lights don't come on any more. Which then brings me to assume the injectors aren't getting enough power to kick on (THANKS NEWZED). So now i just have to find a way to bypass all the wiring to the dropping resistors to a good 12volt source, any suggestions? I been searching Hybridz to see what people have done when they swap from 81 to 82-83 ecu, but i haven't found an answer yet.

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You're welcome. But. I think that dropping resistors are matched to the injectors (according the FSM the 81 turbo engine uses a dropping resistor, it's described in the 81 Turbo Supplement) to control current flow through them. The ECU or E.C.C.S just supplies the ground. I could be wrong though, I don't have a turbo motor.

 

You could check you CSV connection for 12 volts when the key is at Start, then pop the CSV out, disconnect the small wire to the starter so it won't crank, turn the key to Start and see if the CSV squirts. Or loosen the hose clamp and see if it leaks, or something similar. A lot of different ways to verify some fuel pressure even if you can't measure it.

 

On the 81 doesn't the fuel pump prime for five seconds when you turn the key to On? You should be able to hear it.

 

I would think that if you had some fuel pressure in the lines, that the CSV would supply enough to at least give you a pop or two. Some people have reported running the engine on a stuck open CSV alone. You might supply a direct 12 volts to the CSV, jump in and see if it starts. Just a wild idea.

 

That's all I have. It sounds like you have everything covered except confirmation of fuel pressure in the lines and injectors opening.

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So I just found the 12v source on the connector that goes to the dropping resistor and jumper the 12v source to all 6 injectors. Tried cranking the motor with the test light connected to one of the injector plugs, but no light. I'm not sure if the way i jumper the pins was correct but I'm running out of ideas. The injectors should of been getting 12 signal with key on, and the ecu should of been supplying the ground. (NewZed) I'm not sure what CSV is but I did just replace my fuel pump with a Walbro running on stock fuel pressure regulator, and according to the fsm 81 uses dropping resistor, but on the 82/83 they removed it, not sure why but on another forum a member claimed that on the 82/83 they made the ecu more "robust" on the ground side.

Edited by voong413
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CSV is Cold Start Valve but maybe the turbo motor doesn't have one. I browsed the supplement and didn't see it.

 

Confirm fuel pressure. Just loosen a hose clamp on the fuel rail and see if gas squirts out. Your FPR and pump should hold pressure for at least a minute or two after trying to start.

 

The dropping resistors save the injector circuit from overheating. I would not run with them bypassed if you have stock injectors.

 

Alright, that really is all I know. Good luck. Confirm fuel pressure.

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3:45pm The engine finally starts! I ended up using the dropping resistors, turns out the car just needed a little more loving. I soaked the bottom end of the injectors in fuel and cleaned them up a bit. Noticed on the ECCS that my TPS wasn't getting signal from time to time, found a loose bolt that grounded the sensor to the throttle. After i got the motor running I tried revving it a little bit, but each time the car would die from me touching the throttle until it warmed up anyways. After the car was warmed up, the throttle response was fine which seems a little weird to me, but BIG THANKS to HybridZ and all the members that helped out!!!

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Glad to hear such a good feeling isn't it? My advice is to ditch the whole 280zxt eccs and go with something more advanced either standalone sds, megasquirt haltech. Or you can go with 300zxt ecu and run nistune. The zxt system is so far behind and very prone to problems.

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  • 1 month later...

From the '81 Turbo Supplement

 

post-5024-020322100 1295149108_thumb.jpg

I've seen your post on l28t swaps my ecu light comes on but goes out as the engine cracks, I have a no start problem, I have spark, fuel pump runs power to injectors but the injectors don't fire. the turbo engine going into 76 280z any ideas

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I would go through and clean all your grounds and connectors,that was my biggest issue. I first had a bad ECU, then Ignitor so no spark, changed that, then no fuel, tested it with starter fluid ran for a little bit. then died. pulled my injector clips and found that it was all corroded so I cleaned that. still no start. Found bad ground, fixed that and it cranked right up. but the ECU light shouldn't turn off on crank, well at least mine didn't.

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  • 2 weeks later...

I had these same problems on my turbo start up. I ran a wire from my FP to the battery so I knew the pump was running and put a fuel pressure guage in the return line to make sure I had pressure. Car would still only run briefly on starter fluid. Took the hose off the 1/2" warm air injection port and the car would run. Adjusted the AFM for more air and that solved the air issue but I still needed starter fluid to get running. Pulled the injectors, flushed and reinstalled. Running great now.

Hope any of this helps.

Bob

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