Mechanics

NISSAN 240SX SENSOR PROBLEM

1989 Nissan 240SX • 200,000 miles

I am trying to fix this car for my young nephew. When u first start it, it runs fine for 15 sec or so. Then it will not run faster than an idle. I checked the fuel injectors resistance and all read about 14 ohms. Injectors wires on cyl 1 and 4 will stall the engine when disconnected. Disconnecting wires on cyl 2 and 3 injectors have no affect at all. I swapped the injectors and had hoped the problem would follow the injectors but it didnt. I have read the mass air flow sensor could cause the inability to accelerate but I am bewildered as to why diconnecting cyl 2 and 3 injector wired has no affect on the engine running. There is a busted sensor screwed in the back of the intake manifold and no one knows what this sensor is. So I am having a hard time replacing it. Is this is the air temp sensor? And could this or the mass air flow sensor be the source of my problem or do you think it is the ECU? Any help would be greatly appreciated. My nephew does'nt have a daddy and I am trying to help him.
Avatar
Jgrene169
November 4, 2012.



Start with a compression test

Roy


Did you check for trouble codes?


KHLow2008
Nov 4, 2012.
I did a compression test. All cylinders are around 150psi.
I checked the trouble codes in all 5 modes after replacing the idle control valve and mass air flow sensor which I knew were bad. (Busted).
It said there was a malfunction in the ECCS and that it was burning rich.
Cylinders 2 and 3 spark plugs were gunked up and they are new.
If I unplug the injector wires going to cyl 2 and 3, the car will rev up but chokes down when trying to rev up with the wires connected.
I have already reversed the injectors 1 with 2 and 3 with 4. The problem did not follow the injectors.
Does this mean the ECU is bad? Is that what controls injector timing? Are the injectors being told to open to far?
I havent had much luck finding out what the ECCS is. Online it said it was behind the throttle body an top of the intake manifold. And that just isnt so.
Ever heard of such a problem! Any help would be appreciated. I'm at a loss here.


Tiny
Jgrene169
Nov 12, 2012.
ECCS - Electronic Concentrated Control System is not a component. It the system named by Nissan for their fuel injection system used in this vehicle.

What are the trouble codes you are getting now after parts replacement?


KHLow2008
Nov 12, 2012.
Well, in mode ONE the red light is illuminated which indicates an ECCS malfunction.
Then in mode TWO the red light is off which indicates it is running rich.
In Mode THREE I have 5 reds and 5 greens which means no fault.
So, what is making it run so ragged above an idle. And why does it run better at a fast rpm with injectors 2 and 3 unplugged?


Tiny
Jgrene169
Nov 13, 2012.
Your code retrieval does not match what I have in our database. Here they are. Let me know if they are what you have done.

ENTERING SELF-DIAGNOSTICS

1. Turn ignition switch to "ON" position. Use a screwdriver to turn ECU diagnostic mode selector fully clockwise.

2. Wait for inspection lights to begin flashing. At this time, inspection lights will flash the mode options (i.E. 2 flashes for Mode 2, etc.). As soon as inspection light flashes the desired mode number (3 flashes for Mode 3), immediately turn mode selector off.

3. If the mode selector is kept in the "ON" position, the mode selections will
continuously cycle (Mode 1 to Mode 2 up to Mode 5, then cycles to Mode 1, etc.) And the process will continue. This will not erase the memory.

RETRIEVING CODES

NOTE: Mode 3 is used to retrieve trouble code(s) from the ECU self-diagnostic system.

Trouble codes are read using the Red and Green LED inspection lights on the side of
the ECU. After selecting mode 3, trouble codes corresponding to that mode will start
flashing. Trouble codes are indicated by the number of flashes from the ECU Red and
Green LED inspection lights. Count the number of flashes. The Red LED indicates the
number of tens while the Green LED indicates the number of ones. For example, 3
flashes of the Red LED followed by 2 flashes of the Green LED would indicate code
32.


KHLow2008
Nov 13, 2012.
Yes, that is exactly what I have done. In mode THREE I get five red flashes and 5 green flashes. This is supposed to represent no faults found. But there is definately a problem.


Tiny
Jgrene169
Nov 14, 2012.
Code 55 means no faults have been detected in the ECCS and the problem is not likely to be sensor or circuit faults.

You have a problem which is more likely to be mechanical or maybe the ECU itself.

Check the spark plug wire. Have them ohmed out and ensure the firing order is correct, 2 and 3 could have been swapped.


KHLow2008
Nov 14, 2012.
I replaced the wires already. But my nephew put plugs in it. It is possible he swapped the wires. Do you know the firing order? BTW Thank you for what y'all do. You seem to really want to help people and you don't see much of that anymore.


Tiny
Jgrene169
Nov 14, 2012.
Firing order is 1-3-4-2, counter-clockwise from top of distributor cap.

We at 2carpros here are always willing to help and would always give it our best shot and I never like to give up until I come to a conclusion. It is my love of helping others and solving problems that keeps me here.

There are many people out there willing to give a helping hand but at times helping others physically can be dangerous as we have cases of rigged accidents etc to rob. Working online we don't have that worry.

Lets hope coming back to basics solves our problem, just some swapped wires, lol


KHLow2008
Nov 14, 2012.