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Discussion Starter #1
Today as I was working on relocating the knock sensor mod, I knoticed im getting intermittant codes 45, 51, and 15.

The only way to read them is through conzult/data scan/other programs.

I think this is because the codes only show up for like a second and disapear.

It hard to clarify, but 95% of the time i will have code 55. But sometimes i will randomly get code 45, 51, or 15 for just a second and then it goes back to 55. This is when idleing and driving.

I know what the codes stand for, but what could be causing them to only trigger for only a second and go away?


I also know one of my injectors is ohming a little out of spec (high)

that might be setting off the injector circuit.


What triggers an inject leak though? (how does the computer know it has one)


Im looking for a consult here.
 

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Discussion Starter #3
i know what the codes mean, but im trying to figure out why they are popping up for only a second and going away.

Im also wondering how the car knows that the injectors are leaking
 

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I could be wrong, but I think that the ECU monitors the fuel pressure for either side of the engine. As for why they might be showing up only once in a while, I could only think that the injector is on its way out and sends the right signal only part of the time, leading the computer to read that the pressure on tha side of the engine is either wrong or right. Unfortunately, the codes are not too helpful with telling you which injector is going nuts so you have to go one by one to see if one or more is acting up. Which I could be more helpful. You might want to ask the all wise JT240Z, that man is the encyclopedia of the Z.
 

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There is no code 15. Are you sure it's not 51 again?
 

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I JUST went through this on the kid's N/A...
1 injector was at about 20 ohms ( static ).. but randomly it would toss the code.. and light the light.. once replaced.. it went away.Most circuts will tell you a value is to high ( or low ) open or shorted.. or the current draw is high or low. like the brake light idiot light! The injector circut works the same way.

Wiring & grounds are critical for the Z to not get a bogus readings from senders and have the ECM send a correction to the engine ( which it doesn't need ) and the performance suffers.. I took a DAY and chased as many grounds as I could and cleaned them up.

NOW no weird intermittent issues, ( just a fair amount of HARD failures ).
Mike
 

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Discussion Starter #7
JT, conzult reads the code as 15 (LEAN MIXTURE) or something like that.

My ECU light has never came on while driving or anything and it always reads 55 when doing the blinking light test using the knob on the ecu itself.

But all the programs i have for the laptop keep reading those three codes every once in a while.
 

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Who's consult program are you using?
 

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Discussion Starter #9
Have used Nissan Data Scan and Conzult. Both show same codes popping up.
 

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Funny... the z32 factory service manual makes no refferance to code 15 and I've never seen it either. Now 51 I've seen a few times. There is a code 15 on a 240sx ECU but the Z32 never listed it as a valid error code.

Either way it seems like you have an intermitant fuel issue based on the other codes.
 

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Discussion Starter #11
hm. Well i know i need to replace the injectors, I'll just wait it out until i can do that.
 

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Caution... You may be running very lean depending on the problem. Check you O2 readings under light load to make sure you're not running lean.
 

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Discussion Starter #13
I did the O2 sensor test and they were blinking quite rapidly and steadily. Both of them.

Much better than my old ones.
 

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This is a California Car? If not, it has a California ECU. Maybe it is throwing those codes because the circuitry isn't present (Non Cali car).


11: Crankshaft position sensor circuit
12: Mass air flow sensor circuit
13: Engine coolant temperature sensor circuit
14: Vehicle speed sensor circuit
21: Ignition signal circuit
31: ECM/ECU
*32: EGR function
33: Heated oxygen sensor circuit (Left side)
34: Knock sensor circuit
*35: EGR temperature sensor circuit
42: Fuel temperature sensor circuit
43: Throttle position sensor circuit
*45: Injector leak
*51: Injector circuit
53: Heated osygen sensor circuit (Right side)
54: Signal circuit from A/T control unit to ECM/ECU (A/T only)
55: No malfunctions in the above circuits

* : Not available for non-california models
 

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See we California guys ROCK!
Post the ECM numbers from the top cover.


Mike
 

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Discussion Starter #16
wow i really didn't know that. I live in Pa, bought the car from a guy in New York who said he got it from a guy in New Jersey X(

I'll have to go grab the numbers off the ecu for you guys this weekend.

If i did have a California spec ecu, how could it mess things up for me?
 

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I'd reprogram it for a Federal tune.
 

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Discussion Starter #18
but if i did have the California ecu, wouldn't I be getting a check engine light for the egr temp sensor?

and just out of pure curiosity, would a California ECU cause performance problems or something in a federal built car?
 

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Let's find out what ECU you have before jumping to fast. A VIN check might be helpful to make sure it wasn't a Cali car to start with.
 

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No but it would say DUDE alot~ Or Bro ( pronounced Brrraaaaaaoo )
Other symptoms:
Drink Corona's & steer towards the beach.
Wear really dark Rayban's
Take the tops off & blast the A/C & Tunes.

It might not light the light.. but it would throw the code.. dude..
( SEE ! )

You could send me your ECM & I can resocket it.. I also have a fed chip.
Bro

Mike
 
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