81 280zx Fuel Injection
07-24-2016, 06:29 PM
#1
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Join Date: Jul 2016
Posts: 3
81 280zx Fuel Injection
Hi i have a 81 280zx that is having some problems. It is originally a NON TURBO l28, but i have added a turbo. However, it is not connected to the intake, its only connected to the exhaust manifold (haven't made a down-pipe or hot-side yet) so the car is running without any boost just as a NA car would.
PS: the car has had this revving problem BEFORE i added the Turbo on it, i was thinking the tune up i did at the same time, would fix my problem.
But it didn't.
I can get it to start up just fine. however, it will not rev past 2k rpm. it seems to break up, and SOUNDS like its being starved for fuel.
With it idling i began removing injector pigtails, and there is no difference, even with almost all the injectors disconnected, it idles the same. The car will NOT start at all if the cold start injector is unplugged, but it will start with ONLY the cold start injector connected, this leads me to believe i am only getting fuel out of the cold start injector, but not the normal injectors.
I have tested the wiring and i am able to get 12v on both side of each injector pigtail, also a clicking sound, from all injectors, when grounding the negative side of the coil.
I have good fuel pressure at the rail. and everything else seems in order but just seems to hit a wall after about 2k rpm.
Any suggestions? i have DVM and factory service manual, but im stuck and need some help!
PS: the car has had this revving problem BEFORE i added the Turbo on it, i was thinking the tune up i did at the same time, would fix my problem.
But it didn't.
I can get it to start up just fine. however, it will not rev past 2k rpm. it seems to break up, and SOUNDS like its being starved for fuel.
With it idling i began removing injector pigtails, and there is no difference, even with almost all the injectors disconnected, it idles the same. The car will NOT start at all if the cold start injector is unplugged, but it will start with ONLY the cold start injector connected, this leads me to believe i am only getting fuel out of the cold start injector, but not the normal injectors.
I have tested the wiring and i am able to get 12v on both side of each injector pigtail, also a clicking sound, from all injectors, when grounding the negative side of the coil.
I have good fuel pressure at the rail. and everything else seems in order but just seems to hit a wall after about 2k rpm.
Any suggestions? i have DVM and factory service manual, but im stuck and need some help!
07-26-2016, 07:26 AM
#2
Mr Z++ Wiki
Join Date: Sep 2009
Location: Victoria, BC
Posts: 2,195
Are you trying to run a turbo on an NA EFI system?
If you pull the injector plugs and it makes no difference those injectors are not working.... you need to address that for starters. You will get +12V on both sides of the injectors if you leave the other injectors in that bank plugged in because the injector is basically a short circuit - a coil of wire. Unplug all the injectors then check each one. Once you verify if you have +12V on one side you need to check and see if the ECU/Resistors are switching ground on.
If you pull the injector plugs and it makes no difference those injectors are not working.... you need to address that for starters. You will get +12V on both sides of the injectors if you leave the other injectors in that bank plugged in because the injector is basically a short circuit - a coil of wire. Unplug all the injectors then check each one. Once you verify if you have +12V on one side you need to check and see if the ECU/Resistors are switching ground on.
07-26-2016, 07:28 AM
#3
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Join Date: Jul 2016
Posts: 3
my problem is: no pulse to injectors....
grounding the negative side of coil with 3 taps makes them fire.
ran tests from the book including:
COLD START VALVE TEST
IGNITION COIL TRIGGER INPUT TEST
IGNITION START SIGNAL TEST
INJECTOR CIRCUIT TESTS
EFI RELAY, FUEL PUMP RELAY-2 AND FUEL PUMP RELAY-3 TESTS
THROTTLE VALVE SWITCH TEST
4 DIFFERENT AIR FLOW METER TESTS
AIR TEMPERATURE SENSOR TEST
CYLINDER HEAD TEMPERATURE SENSOR TEST
EXHAUST GAS SENSOR CIRCUIT TEST
THERMOTIME SWITCH TEST
CONTROL UNIT GROUND CIRCUIT TESTS
AIR REGULATOR AND FUEL PUMP RELAY-1 TEST
found out my cold start valve had the wrong connector on it. also found out my fuel pump runs constantly with key in on position.
everything else tested normal and within specs from the book.
Fuel injectors are not pulsing....
grounding the negative side of coil with 3 taps makes them fire.
ran tests from the book including:
COLD START VALVE TEST
IGNITION COIL TRIGGER INPUT TEST
IGNITION START SIGNAL TEST
INJECTOR CIRCUIT TESTS
EFI RELAY, FUEL PUMP RELAY-2 AND FUEL PUMP RELAY-3 TESTS
THROTTLE VALVE SWITCH TEST
4 DIFFERENT AIR FLOW METER TESTS
AIR TEMPERATURE SENSOR TEST
CYLINDER HEAD TEMPERATURE SENSOR TEST
EXHAUST GAS SENSOR CIRCUIT TEST
THERMOTIME SWITCH TEST
CONTROL UNIT GROUND CIRCUIT TESTS
AIR REGULATOR AND FUEL PUMP RELAY-1 TEST
found out my cold start valve had the wrong connector on it. also found out my fuel pump runs constantly with key in on position.
everything else tested normal and within specs from the book.
Fuel injectors are not pulsing....
Last edited by 81zTurbo; 07-26-2016 at 07:30 AM.
07-26-2016, 08:01 AM
#4
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Thread Starter
Join Date: Jul 2016
Posts: 3
forgot to add:
with all the injectors connectors removed, i have 12 volts on one side of each. the other side of each has power also, but not a full 12 v when all connectors are disconnected, seems to bounce around 3v-4v?
cant get noid light to pulse
with all the injectors connectors removed, i have 12 volts on one side of each. the other side of each has power also, but not a full 12 v when all connectors are disconnected, seems to bounce around 3v-4v?
cant get noid light to pulse
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