Jaketenpointo

Background:

Car was idling fine, driving fine, good consistent compression across all cylinders. Then one night I jump in and notice it is running on 3 cylinders. Start checking spark and fuel. Appears to be the #2 injector not firing at all. (ie. unplugging doesn't change anything).

Fast forward a few busy school/work weeks and I end up swapping injectors and still the same dead #2. Swap another still dead. Swap between known working injectors in the car (1 swapped for 2), still dead #2.

Now I am at the conclusion that it is either the ECU or the wiring. Borrowed an ECU from a pristine S13 coupe (albeit overpriced), still no change. But prior to swapping ECUs my ecu gave code 55. The borrowed ECU was shooting 34 and 14.
Which according to this:
KA24DEvelopment.com :: ECU Diagnostics

Means 34 (knock sensor) and 14 (open speed sensor circuit). I don't know why one ECU catches it but the other doesn't.

So basically the symptoms are:

• Terrible Idle
• Gassy Exhaust
• #2 cylinder unchanged when unplugged
• ECU swapped makes no change

What is going on here and what is the solution?

Thanks for your help and time,
Jake

Current theory is the harness, and friend suggested splicing the #2 and #3 injector wiring together because they fire together. What do ya'll think?

hassanbakar123

so have you check compression since this has happened?

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mxexux

You have successfully figured out that it is not a fuel problem. Now you need to start checking for spark. Check spark plugs and wires.

Jaketenpointo

How do you figure? Im saying that it may not be a fuel injector problem, but it may be a injector wiring problem.

Ive tested for spark. Pulled the wire and it arcs to the block. Swapped for different sparkplugs. No change.

So either compression magically took a dump (still need to pickup a compression tester). Or.....

Ive read to hook up a voltmeter to one prong on the injector harness and it should be constant, then try the other and it should be pulsing. If one isn't pulsing, tap into #3 injector pulse wire. If the constant isn't on, tap into #3 constant.

mxexux

An easier way to check if the injector is actuating is by getting yourself one of those automotive stethoscopes that can be found pretty cheap at the auto parts stores. Or if your a really cheap bastard you can use a long screwdriver, but it is more difficult to tell. Basically your putting the stethoscope or screwdriver to the injectors while it is running and listening for a very distinct rapid tapping sound.

Another way would be to borrow or rent a noid light set which are little lights that plug into the injector connector. When the engine is running the noid light should be pulsing on and off.

If then you are sure that the injector wiring is bad, then I would go no further without an FSM. I wouldn't tap into another injector wiring because you would risk burning out the ECU. Each injector has its own circuit going into the ECU. Trying to run 2 injectors on one circuit would most likely overload the circuit and make your ECU smoke. Unfortunately these circuits are not protected by fuses either.

Good luck.

vervedatsun

i am trying to figure out if I want to but my friends car,
its a datsun 510 with a 94 ka24de swap he hasn't had it running in a while and it was apart( head on but no valve cover, long story) valve cover off injectors out too i put it all back together, yesterday
First thing i have spark no idea if its the correct firing order,but i have heard engines on the wrong firing order and you still occasionally get a weird bump or ignite combustion noise.
so that leads me to check the injectors for any current, or pulsating going on when engine is turning over.
The injectors have a constant current going, my dad stabbed the wire with a 6v/12v tester while the key turns on adn the current goes away when key is off of course.... i dont have a injector tester,and the injectors themselves look a little worn out but i am not getting any fuel from any of them, you figure at least one would be working, but am getting spark.
Any help please!!!

Jaketenpointo

You need to verify that the cam timing is 100% correct. If its even slightly off, it won't start. Then make sure your distributor is stabbed correctly. Then make sure your wires go 1-2-4-3 (clockwise from the 9 o'clock)

CHECK THE TIMING (igntion AND Cam). Either that or give the car to me.


On my car the compression is completely fine. So....

Possible suspects:
Compression (X)
Injector (X)
ECU (X)
Harness

Thats gotta be it. Yay or nay?

jin8544

its electrical problem

hit me up of your in socal i can fix it.