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L28E: Stalling when warm.


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Hello everyone,

Many have said I'm pretty young be in possession of a Datsun, however I've been maintaining quite well thanks to the FSM. I purchased this car as my first car during highschool from money I've earned as a mechanic's apprentice. I got the car in non-running condition as it has sat in a carport since 1989. I managed to get it running quite well after replacing fuel pump, fuel filter, afm, dropping resistors, distributor, and the coolant sensor, then proceeded to cleaning the fuel tank. 

Recently I've been having an interment loss of power at around 3k-4k rpms only while moving, sitting idle it can rev to skies but not while moving. I thought it might be the injectors so I replaced the injectors, no noticeable difference.

 

**(Now here's the serious problem)**I then changed the injector connectors from the harness, and now it runs like crap, horrible idle and definitely a loud, noticeable misfire and clacking/grinding sound at idle. When moving in 1st gear, it moves fine until warm, then when moving in every gear causes a stall if I press the throttle. 

Could it be the ECU? Incorrect injector wiring (more than likely)? Thermotime switch (I thought the ca wouldn't run if it's bad, right?) ?
Thank you for any advice on this matter
-Shuu Takemura-

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On 8/16/2018 at 8:06 PM, HuD 91gt said:

If the problem got worse, I’d check all your new connections. If it’s still bad, look at the harness or any other areas which may have been disturbed in the process of putting in those new connectors.

Thanks so much for the response. I checked all the connections and everything's A-OK in that department.

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On 8/15/2018 at 6:18 PM, TakemuraShuu said:

Recently I've been having an interment loss of power at around 3k-4k rpms only while moving, sitting idle it can rev to skies but not while moving. I thought it might be the injectors so I replaced the injectors, no noticeable difference.

 

**(Now here's the serious problem)**I then changed the injector connectors from the harness, and now it runs like crap, horrible idle and definitely a loud, noticeable misfire and clacking/grinding sound at idle. When moving in 1st gear, it moves fine until warm, then when moving in every gear causes a stall if I press the throttle. 

 

The injectors all open at the same time, so mixing injector connectors won't do anything.  If you ONLY replaced injector connectors and this problem occurred then I'd say make sure that all of the injectors have power and are connected to the ECU.  Both pins doing what they should do.

 

Because all of the injectors open at the same time and because things are rich when cold, you might have cylinders running on fuel from neighboring cylinders.  As it warms up and at higher RPM things will get lean which causes backfires and other problems.  Check your injectors for power and continuity, at the ECU connector in the cabin.

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14 hours ago, NewZed said:

 

The injectors all open at the same time, so mixing injector connectors won't do anything.  If you ONLY replaced injector connectors and this problem occurred then I'd say make sure that all of the injectors have power and are connected to the ECU.  Both pins doing what they should do.

 

Because all of the injectors open at the same time and because things are rich when cold, you might have cylinders running on fuel from neighboring cylinders.  As it warms up and at higher RPM things will get lean which causes backfires and other problems.  Check your injectors for power and continuity, at the ECU connector in the cabin.

Thanks so much for the response. When checking the connection for the injector harness, is there a specific way to check it?. Because if I run a multimeter to either of wires of an injector harness with key in On Position, I get power to both wires. The injector wires aren't color coded so I probably goofed the wiring somewhere.

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Download the first book here, the 1980 EFI Manual.  It covers all years through 1980.  Go to electrical tests and do the tests at the ECU connector as shown.  Good luck.

 

Power on both pins is normal if you test one connector at a time and others are plugged in.  It's a parallel circuit, power comes from the dropping resistors.

 

http://www.xenonzcar.com/s130/other.php

Edited by NewZed
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