Lycan_leader

Hello, i own an 300ZX VG30DE '96 and have the following issue:
When i ride my car, i feel that my Z is going to slow, like when an ignition coil is turning off and turning on inmediatly. I connect an ODB2 Scanner and it's read some ingnition inputs failure and also i erased the error codes and the promblems continue, i already replaced all 6 ignition coils and the problem continue, please help me about that, i believe that is the ignition module. please help me about that, please....

Thanks a lot.

b300z

have you checked your spark plugs, injectors, or coil packs separately to see if they work?

hesisation can be caused by a lot of other things as well.
go around and check your electrical connections. make sure they're clean, connected. look for a vaccum leak as well. there are many many many many too many hoses on this engine

91zxtt

Could be your PTU, but since it seems to be an intermittent electrical issue, then I would check all of the grounds.

lightspeed

Could you be a bit more specific? A Z that feels like it is going slow may simply be a result of not mashing on the right pedal hard enough.

Did you REALLY expect that erasing the codes that have been thrown to help the problem?!?

Seriously Lycan_leader, some more info would be helpful. I have spent the last YEAR pursuing a very annoying hesitation problem on my '96 VG30DE and am finally getting to the bottom of it. I would be glad to pass on what I have learned, but you haven't give us much to go on.

(My hesitation was 2500-3300rpm's which was slight under most conditions, but a ignition cut-off, sever jerking when excellerating mildly after a couple of "spirited" accelerations. Above 3300, reasonably smooth. Sound familiar?)

Start with a better description of the car...Trans (Auto or Manual) modifications, recent work on the car (ECU/UDP's/Belts/maintenance), and any diagnostics that you've done.

Lycan_leader

Sorry for delay friends, ok, exactly my problems are:
- Intermitent turning off and on of coil packs
- Gas Smell
- An extreme expensive of fuel ($$$)
I already erased the ECU codes, and only de ECU code remaing is the Knock Sensor (you think that the Knock Sensor can do that?)
I already replaced all 6 coil PACK
I already replaced the MAF sensor and the Igniter Module, and the problem persist.
I Already replaced all 6 spark plugs (iridium)
my Z is a M/T and no mechanical works realized just checking
All Belts are smooth and fine, no engine modification (Stock car) just replaced the original Air filter with an HKS Power Flow filter (with the adapter)
and also the CHECK ENGINE never ever is turning on, just when i turn on my car for just 1 or 2 seconds and its going off after.

Please help about that, i will going to destroy or my Z.

Thanks...

Zgringo

If you have a knock sensor code you could have a problem with it. The knock sensor retards the timing and enriches the fuel maps to protect the engine from detonation and that would cut your power alot.

Lycan_leader

ummm, ok, i will try to buy a new one, you know what place or web sale it?
thanks for you appreciated help.


If i the problem persists, any other solution friends?

thanks a lot.

Shameless

www.courtesyparts.com

91zxtt

Buying a knock sensor is easy. Installing it is not.

Buying random parts is not the way to fix your problem. You're on a wild goose chase.

Start with the simple things.

Just for fun, run an ECU diagnostic to see if it has stored a fault code. That's where I would start.


After that, do this...
1) Clean your throttle bodies.
2) Replace the PCV valves.
3) Lose the Iridium plugs and replace them with the OEM NGK's. NGK's are proven to work better.
4) Check for vacuum leaks.
5) Replace your fuel filter. Use OEM.


To fix the fuel smell problem, try tightening all of your fuel line clamps. If that doesn't work, then you may have to replace the hoses.

A hesitation at 2500-3000 RPM's could be an EGR valve; which is harder to replace than the knock sensor. Pray that the culprit isn't either one of those.

Zgringo

Thanks 91zxtt, It seems like everyone is ready to change parts without trouble shooting the problem. It might be as simple as a bad connection. Now wouldn't you feel like a smuck if you tore you engine down only to find it was a bad connection.
Start with the simplest and work from there.

Riz Z Speed

didn't someone just post similiar symptoms recently and just found that the timing was off?

Zgringo

Thanks Rizz, you just helped me make my point.

CanyonCarver

As in try the "search" button????

lightspeed

Sure. Check your pm's

Lycan_leader

Ok friends, i just realized another ECU diagnosis and the knock sensor error still appear, i bought a new knock sensor and actually i´m work with it, when i finish to do my work i will prompt you for the results.
Sorry for my english, but i´m latino from Panama country
thanks a lot friends...

lightspeed

Details, guys, details! Under what conditions is it misfiring now and what did you do?

lightspeed

I've been asked to provide some details on how I resolved my studder problem, and I'd thought I put it out her in hopes it'll be valuable to others. (My Z is a '96 which is VERY different than '90-'95's in some ways, particularly the ECU.)

First, if you are having the SAME issue as I did, then advancing the timing slightly might help. ***Mark your original setting before starting.*** About 2-3 degree would be significant. That is accoumplished by moving the CAS to the LEFT about 1/16" to 1/8". See if this helps. I really do recommend that you make this adjustement with the help of a good timing light before you start the motor. My Z is a '96 and the normal timing is 10degrees and all others are 15degrees. That is where I got bit - I trusted a mechanic to know that. Here are some instructions...
http://www.ttzd.com/tech/timing/timing.html

I found a good bit of improvement after cleaning the throttle bodies and doing "the sea foam thing." Here is my original posting...
https://www.zdriver.com/forum/showthread.php?t=10058

and another high idle issue where I mentioned it some more...
https://www.zdriver.com/forum/showthread.php?t=10057

and here a thread with an excellent "how to" on doing "the sea foam thing." See comment by tangeray.
https://www.zdriver.com/forum/showthread.php?t=11863

Here are some excellent links for chasing "the studder" or "the hesitation" issue that is VERY common to Z's.
http://zhome.com/ZCMnL/PICS/hesitation/hesitation.html (the rosetta stone for chasing this issue around...)
http://www.twinturbo.net/ttnetfaq/FA...hesitate2.html (quite good)
http://www.twinturbo.net/net/viewmsg...msg_id=1035377 (grounding net helped here. I did this, no big changes...)
http://www.twinturbo.net/net/viewmsg...&msg_id=855473 (middle of the article has a bunch of links...)

There is no substitue for reading the factory service manual a.k.a "FSM" Here is a section that plows through this issue...
http://300zx-twinturbo.com/cgi-bin/m...ault&total=190

I would suggest that you consider vacuum leaks - a common problem that can drive you NUTS. The leak tester from BoostPro.net is a cheap, innovative tool that allows you to pressurize your intake plenum and listen for squeals. Seems that the oil dip stick is a common problem I got this tool, but have not used it.
http://www.boostpro.net/prodz32tester.html

If you are planning to own your Z for very long, and you have some computer savy, you MUST get an interface to your ECU. My favorite is also the cheapest on the market. About 145$US. This is for the cable AND the software, and they are constantly selling out. Get on the list. Some of the best money I spent on the Z.
http://www.plmsdevelopments.com/consult_if.htm

lightspeed

Uh, let me get this right. YOU grab a coil pack, and YOUR BUDDY fires the ignition?!? You did all six that way?!? For most individuals, testing the first coil pack would represent a self-rectifying-behavior-pattern. Man, what do you do for an encore? ROTFL

Actually there are easier ways to do that. For example, use the ECU interface I mentioned earlier and sequentially turn each cylinder off and on. Another approach that works in most cases is to remove the spark plug, reattach the coil pack, and ground the base of the plug and step back. THEN fire the ignition and LOOK for the spark. Your technique is just a bit too close to sticking your finger in a light socket.

Seriously, glad you found the prob. Good sleuthing. Stay in touch and keep us posted.

Riz Z Speed

i did that to my friend the other day
i was checkin for spark in my roommates integra,
i'm like, "Here, hold this." as i hand him a wire.
and i crank the motor he drops it like a hot potato!!
i couldn't stop laughing for like 15 mins!!
that little story brings back great memories and a huge smile on my face!

1ntegtype1

Yeah i realized that there are easier ways to do it. I just didnt have the equipment. Nothing more frustrating than adding more frustration by not having the correct tools. That hesitation problem bugs the crap out of me.

91zxtt

I'm still laughing. Usually, if someone gets nailed by a coil they say to themselves, "Mental note,...don't do that again." Once is more than enough to tell someone that they shouldn't be doing it. I don't what I can say about someone that does it 6 times. One quote comes to mind though....."Stupid is as stupid does."

CanyonCarver

I tried to stay quiet..... but, you talk about a shocker. One time late at nite, we just installed a motor, fired it up, throttle stuck wide open, I leaned over up against a chassis tube, grabbed the coil wire to pull it out and got the shock of my life. The current went threw me and back out to the chassis about an inch from the nads. Had a nice red burn spot for a week. MSD ignitions at 8000 rpm do put out the juice.

lightspeed

Yeah, CanyonCarver, but at least you were trying to STOP a runaway engine. There is consolilation in that!

Zgringo

I don't know if any of you are old enough to remember the model "T" coil, but we use to wire one to the back seat with a switch and when you flipped the switch anyone setting in the back seat got it.

1ntegtype1

HAHAHAHAHAHAHA no guts no glory but thick rubber gloves works great. I didn't get that much of a shock that you guys mention. And like I said that problem gotten me crazy.