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Z32 Initial Diagnostic Tool, Pulling ECU Codes - official Niky-Tech-Sticky
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Author Topic: Z32 Initial Diagnostic Tool, Pulling ECU Codes - official Niky-Tech-Sticky  (Read 15526 times)
niky
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« on: September 17, 2009, 01:19 PM »

With the increasing number of Z32s joining the forum as of recent, I've been running into more and more posts asking for Z32 technical support. I am more then willing to try to help out as best I can over the internet... HOWEVER... there is some basic info that needs to be presented BEFORE any diagnostics or problem tracking can begin.

Being a diagnostic technician, and having to solve engine problems in a daily basis, I have run into almost every manufacturer's method of providing diagnostic information from car to person. Excluding the '96 Z32s... every other year runs what's called an OBDI computer system. OBDI systems are known for their lack of any helpful information and their ability to only display the bare minimal ammount of information in order to function. The Z32 is an exception to this comon trend.

The Z32 trumps any other OBDI system I have ever run into. It also is one of the most complicated engines I have ever run into. For these reasons it becomes absolutely NECESSARY TO PULL CODES FROM THE ECU IN ORDER TO EVEN BEGIN TO GET STARTED TRACKING DOWN A PROBLEM.


Twin Turbo Z's of Dallas has a great write-up explaining how to retreive ECU codes, so I won't try to best them and just post the link up. -> http://www.ttzd.com/tech/diagnostictech.html <- This can be done with a 10mm socket and wrench and can be done with a small flat-head screwdriver without removing the ECU if your a little bit flexable and have good eyes. If you have any questions retrieving codes please ask and I will try to give you some more information as to how to do this. Basically all your doing is counting the number of flashes (fast and slow) from the check engine light, turning those flashes into numbers, and those numbers into codes. The website also has a full listing of all the codes and their meaning.




Now that we have that out of the way... please be as specific as possible. The more information that is presented, the easier it will be to track down the problem.

Example... "My car has a missfire"...... ok, this is a problem, but more info would be needed to get started....

Example... "My car runs fine at idle and at a steady cruise, but when I get on it, it missfires under boost in the higher RPMs. When I let off it runs fine again. It seems to get worse when the weather is colder." ... there's alot more specific info listed there and that makes it alot more helpful to give you some answers.




« Last Edit: October 11, 2011, 09:40 AM by niky » Logged

niky
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« Reply #1 on: September 17, 2009, 01:24 PM »

I would also like to post up how to do a proper balance test and how to ohm injectors in order to isolate missfire issues... but I've run out of steam for now and would like to take or gather some pictures to help out visually explain things.

Mods... please feel free to PM me about ideas, necessary changes, or missing information. I kind of typed this up pretty quick.
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adamvann3
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z31


« Reply #2 on: September 17, 2009, 01:41 PM »

Awesome tool that needed to be posted.  Thanks
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BlackRob183

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« Reply #3 on: September 18, 2009, 08:57 AM »

Thanks again for the post as I haven't tried it yet but it's on my to do list along with a bunch of other car crap  Tongue
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TraBis

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Formally tmeyer29


« Reply #4 on: September 18, 2009, 10:08 AM »

Nissan data scan FTW!
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niky
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« Reply #5 on: September 18, 2009, 09:01 PM »

MISSFIRES

Engine shakes at idle?... sounds like it's skipping a beat when revving?.... feels sluggish? ...

Missfires being a common issue with The VG30de(tt) platform, I feel it necessary to include into any basic online diagnostic toolbox. This being only a basic diagnostic description, I won't get into any really advanced methods and just try to keep it geared more towards the at-home-do-it-yourselfer. Missfires can be caused by anything from high resistance in a wire, to mechanical engine damage. This isn't the end all of explainations.... but it's a starting point.

Generally most missfires you run into with Z32's are the result of one or more dead cyclinders, and the info below will help you track down some common causes.


Power balance test.

This is by far the simplist, fastest, and easiest of all tests, and best of all it requires no tools. (although a medium sized flat head screwdriver does help)


Simply pop the hood, start the car, and get ready to figure out the dead cyclinder. Begin by removing the electrical connector from one of the coil packs. (it helps to do this in some sort of pattern to help you remember, I like to do this one bank of the engine at a time front to back.) Listen very carefully to what happens to the idle of the car when you do this. It should begin running rough or even stall. You should be able to audiably hear a change in the engines sound.

Plug the connector back in and again listen for a change in sound... it should change back almost immediately to what it sounded like before the connector was removed and the idle should improve. Leave the harness connected and repeat this for the other 5 cyclinders. ....yes it is possible to remove the connectors way in the back of the engine without removing other things to get to them.







.... out to bar.... will finish up later...
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niky
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« Reply #6 on: February 17, 2010, 09:00 PM »

I know, I know... no updates, no pics.... my bad. Been too busy with the winter Z project to get into any of that.

This is a link to a very comprehensive list of technical TTZ write-ups. Lots and lots of very good info right at your finger tips.

http://www.ttxtz.com/tech.html#oil

Enjoy Smiley
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niky
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« Reply #7 on: March 15, 2010, 09:37 AM »

CHECKING FOR PROPER OPERATION OF THE INJECTOR CIRCUIT.



Z32's are a little different....

Disconnect all of your injector clips before you test, and during this entire process.

You can't check for ground because our injectors are powered all the time. There is a wire that goes from the battery + terminal, to the fusebox  (I'm almost positive it's the one right next to the battery) through a fuse..... directly to each injector. They all share this same power wire. Injector operation is acheieved by a negative trigger to ground directly from the computer..... so when you've got all of your power wires straight, you need to check for a negative pulse from the ECU wire (or non-power supply line).... which means your going to have to have somebody crank the car over when you do this.

All your looking for is one wire with constant power.... and another that has a pulse to ground while cranking..... check all 6 one by one.

Check injector resistance... should be 10-14 ohms.
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niky
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« Reply #8 on: March 15, 2010, 09:46 AM »

The online Z32 300zx Factory Service Manual (or since us mechanics love acronyms... FSM)
can be found here....

http://300zx-twinturbo.com/cgi-bin/manual.cgi

It's the most comprehensive one I've found to date.... and covers TT, N/A, auto, 5 speed, RHD and LHD cars.
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T_wheel300zx

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What's high end HP without low end Torque


« Reply #9 on: May 17, 2010, 12:40 PM »

Thanx niky this was awesome!!!  since I've only worked on straight 4s before I had my 300 I woulda never knew it was misfiring!  Especially with ur loud ass exhaust!  Cheesy
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'90 Z32 turbo swap(JDM import motor), N/A Differential, AMS suspension, HKS turbo timer, Z1 hardpipes, Z1 oil cooling system, Denso Iridium plugs, Z1 BOVs, more to come...
cat35
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« Reply #10 on: October 15, 2010, 12:09 PM »

With all this effort......You........are a God!! Cool
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                                 "Love Cars, Love People, Love Life." - Yutaka Kata
niky
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« Reply #11 on: October 15, 2010, 01:59 PM »

Quote from: cat35

With all this effort......You........are a God!! Cool

Smiley thanks Cat. Buy a Z32 so I can teach you how to fix it when it breaks from all those performance mods I'll pressure you into installing. Wink
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niky
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« Reply #12 on: November 02, 2010, 09:35 PM »

I was recently discussing some Z32 problems with someone and figured I wouldn't let me lengthy typing go to waste. this and the following post are a modified version of the conversation detailing some of the information I covered.

replacing fuel injectors.......

...make sure that the lower fuel injector o-rings are seated properly and not leaking gasoline into the cyclinders. If,
after instilation, the car runs rough (more specifically more rough then it did before), change the oil, you can then smell the oil dipstick after running or cranking the car for about 10 minutes. If it smells like gas this could help confirm that the lower fuel injector o-ring is improperly seated, although extended crank/run time would cause gas to bypass the rings and cause the same smell of gasoline as well..... so re-smell it after one minute.... two minutes... three minutes... etc....The lower o-rings have a habit of pinching during instilation and allowing fuel from the rail to leak past and cause an extremely rich mix (to the point of flooding and in some cases hydrolock and bent rods) it's a big no-no on this engine in particular.The o-rings have to be new and they have to fit on the injector and in the fuel rail snugly. A small ammount of lithium grease should coat the entirety of the upper (and especually lower) fuel injector o-rings during instilation to ensure the o-ring is able to slide into it's final resting place (which is an extremely tight fit).


also do not substitute engine oil for lithium grease... the gasoline will act like a solvent towards the oil and wash away any engine oil you put on... causing the o-ring to actually be more suseptable to sticking against the wall of the fuel rail during instilation.
« Last Edit: November 02, 2010, 09:37 PM by niky » Logged

niky
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« Reply #13 on: November 02, 2010, 09:57 PM »


Technical Crank Angle Senser Theory / Technical description of operation....
The CAS directly controlls the coil packs individually, so if the CAS is bad you wont get spark out of one, some, several, or any coil packs. A positive pulse (the firing signal) comes from the CAS.... (on individual wires) to the PTU (power transister unit) ((which is nothing more then a signal booster))...

...(((The CAS sends out a low voltage input on one wire per cyclinder to the PTU which then converts the low voltage pulse into a high voltage pulse))) the high voltage pulse from the PTU then goes through an individual wire
 (one per coil) to signal the coil to fire. This is why it is so important to understand that you need to test
each respective coil pack individually on it's respective pigtail in the harness directly from its respective cyclinder.

Basically...you can't prove that anything is bad by just swapping coil packs around unless you physically can see a cyclinder not firing, and swap it out with a known working coil pack to determine if the problem is a bad coil pack (which is very uncommon) or bad wiring (which is very common).

*Remember- your not looking for cyclinders that are firing to eliminate ones that are not......
Your looking for cyclinders that are not firing in order to eliminate ones that are.*


To verify firing order........
(more specifically... that you have the coil pack wiring pigtails going to the correct coil packs)........

Turn the CAS [(the shaft of the CAS after removing the sensor) (in the direction of engine rotation) ... but you should have already known all that] with all of the coilpacks grounded; firing order is 123456 starting
 with 1 being the front passanger side, 2 being the front drivers side... and so on.... obviously looking for the coilpacks to spark in their appropriate sequence..... remembering of corse that #1 will only be the first to fire if the engine is at TDC...........

*HINT* this may be a good way to make sure that you didn't accidentally install the timing belt with the camshafts upside down after it's replacement when you cant figure out why the engine won't start with good spark, fuel and compression.
« Last Edit: November 02, 2010, 10:00 PM by niky » Logged

niky
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« Reply #14 on: November 02, 2010, 10:07 PM »

One last thing for the night since I'm using Zcrew right now to avoid writing a research paper....

I found an awsome website that is basically the central hub for links pertaining to anything and everything that is on the internet reguarding Z32's from history and reviews, to tech, to videos, to other enthusiust sites, and everything in-between.

http://www.ttxtz.com/links.html#tech

It's definately a good way for a Z32 enthusiust to kill a weeks worth of rainy days in front of the computer.
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