83 200sx problems

[83200sx]

I inherited this 200sx from some friends at the church. It was parked for over 14 years, and we have been working for over 3 months trying to get it running properly. We have diagnosed a computer problem causing the injectors to not fire, and basically it was trying to run off the cold start injector. We had a trusted friend replace some diodes on the circuit board, and the car ran great when installed back in the car. It is now running poorly again, no injector pulse, and the computer tests bad again. We cannot locate the dropping resistor for the fuel injectors, but suspect that could be causing the computer problems. Any help would be greatly appreciated. This car is in too good a shape to condemn to the crusher!

[Digi7al Trauma]

I inherited this 200sx from some friends at the church. It was parked for over 14 years, and we have been working for over 3 months trying to get it running properly. We have diagnosed a computer problem causing the injectors to not fire, and basically it was trying to run off the cold start injector. We had a trusted friend replace some diodes on the circuit board, and the car ran great when installed back in the car. It is now running poorly again, no injector pulse, and the computer tests bad again. We cannot locate the dropping resistor for the fuel injectors, but suspect that could be causing the computer problems. Any help would be greatly appreciated. This car is in too good a shape to condemn to the crusher!

 

 

Actually from the sounds of it, i dont think your system has injector resitors in it. An injector resistor will be installed whenever the stock high-impedence injectors are swapped out for (often larger) low-impedence models. And from the sounds of it the injectors are oem/origionals, but you should check the impedences on them regardless. If the injector impedence is lower than normal ( ex 2ohm instead of 4ohm) then you could be running current that is easily 2times what the circuit can handle. Wich would explain why the circuit keeps getting fried. And hell if thats not the case, follow the wiring, and make sure there arent any shorts, and if it comes down to it you can run to like rusty's or jacksons auto salvage in raleigh or mclambs in fuquay-varina, and pick up a different circuit board (last time i saw they all had a few 200sx's).... and of course theres the possibility you will have to install a resistor box for them (if they are low impedence injectors) and as allways good luck

 

 

 

"Each injector has 2 wires on it, a red (power) wire and a different color (ground) wire.(The colors are different so that you can look in the manual and find out which gound goes to which cylinder.Mixing these up will cause you huge problems.)

 

If you look on the wiring diagram in the FSM, you will see that a short distance from the injectors, each of the power wires for the individual injectors combine into one single power wire which goes directly to the ECU.It is easiest to install the resistor box if you find this spot first.

 

Note again this is the factory wiring where the 1 wire splits into 4 for each of the injectors.This spot is right near the information plate on the firewall of the engine bay. You can see that I cut the power wire a few inches back from the point where it splits.This is where I will install the injector resistor box.

 

The DSM box has 5 wires on it.4 black wires which go to the individual injectors, and one white wire which is the power source.Attach the black wires to the 4 red wires after the split in the factory wiring, as shown, and the white wire to the ECU SIDE of the factory red wire (to the left as you are looking at the engine) Notice how the resistor box now takes power from the ECU, and sends out 4 power wires to the injectors.

 

It does not matter which of the black wires goes to which of the 4 red wires… all 4 supply a constant 12 volts to the injectors, so it does not matter if you mix them up at all.(Note the same is NOT true for the colored ground wires, which need to remain in a particular order.You should not mess with the ground wires at all during this install!)Last step is to mount your injector resistor box and tape everything up nicely.It helps to use wire loom as well to make everything look uniform." - nissan forum

[datsunaholic]

'83 didn't have dropping resistors. That's why you can't use an earlier ECU... I had an '83, it was a major issue since the ECU was bad and it's a one-year ECU. Mine, the injectors stayed OPEN all the time and filled the oil pan with fuel.

 

The injectors on mine, and per the wiring diagram, were HOT all the time, the ECU provided switched ground. My bad ECU had ground to 2 injectors all the time. One transistor fired 2 injectors, the ECU only had 2 power transistors. I made it run well enough to drive it onto a trailer by using a somewhat easier to get '83 280ZX ECU. It ran, but the tach and such didn't work.

 

Oh, and as far as I could tell it didn't matter what injector wire went where. They're batch fire. All fire simultaneously.

[herculesinwyoming]

Probably wont help, My first car was an 81 200sx. I had a no start issue and it turned out to be water in the right rear passenger side floor board, its been a long time but i recall an electrical conector there or some thing similar. I never could figure out where the water came from

[datzenmike]

Forgot about the dropping resistors Doug. You're correct.. there are no dropping resistors for '82-'83. Or to be more correct the dropping resistors used in the earlier '80 and '81 and not used in the '82-'83 cars.

 

'80 dropping resistors.... 22698 N4202 to 07 '80

'81 dropping resistors.... 22698 W1401 from 08 '80 to 06 '81

 

nothing listed after.

[83200sx]

Well, that would explain why we could not locate it! We tested the injectors, and they all test right near the spec that Alldata gave me. Could not find anything wrong in the computer when we opened it. Put everything back together and the car runs great! It has to be a bad connection somewhere. We are going to check the ECM and injector connectors and replace the negative battery cable as it is starting to fray near the battery. Thanks for all the good info and I will keep everyone posted as to the progress we make and hope to get some pics up soon! Good to have a place where people appreciate these old cars!