Please Help! My Z won't start!

[magalehz32]

The problem started when I was driving in the freeway doing about 70 M/H. Suddenly, the engine just stopped running! I tried to start it again while the car was still driving, it cranks but the engine won't start.
I managed to pull it to the the emergency lane miraculously, since it was in the rush hour and the steering wheel and the brakes became so heavy to operate. Now I don't have any clue what is the problem. the fuel pump seems to be working because I hear it running when I turn the key on. the starter cranks. I don't think its the alternator since the battery was pretty much full when the incident happened. I believe that it has something to do with the ignition circuit. but its my first Z and I don't have any idea of how to diagnose it. did this happened to someone of you guys before? I don't really know where to start?

And by the way I am new to the forum. you don't really appreciate having a website like this till you got in trouble.. :P

Car: 1993 Z32 2+2 N/A

[BlackWidowZ]

ecu codes. Do this test here and then post what your findings are... http://www.nicoclub.com/archives/nissan ... ostic.html

If the motor is turning over its not the starter relay. you need 4 things basically, air, fuel, spark, compression...start there also check your fuses. get ecu code

if you dont have spark
look for green corrosion on ptu Power Transister Unit connectors. PTU is bad... CAS Crank Angle Sensor is bad..coil packs bad

not getting fuel. fuel pump bad..gas leak from fuel line bad...

its pretty had not to be getting air...

you might want to do a compression test...

check to see the timing belt isnt snaped....

check fues.

check ecu code...

[Ace2cool]

Welcome to NICO.

+1 on ECU codes.

BlackWidowZ covered most of the main issues. My main points to check would be CAS, PTU, fuses/relays, and respective connectors, since it shut off all of a sudden and won't fire.

Have you verified spark? Pull the spark plug, ground it to the plenum, and crank it over, and see if the plug fires. If it doesn't, then it's either a PTU or CAS problem.

Do you have the old style or new style PTU? Old is silver, new is black. Old style had a recall, and will be replaced by Nissan with a pigtail harness for free.

[magalehz32]

Hello guys.
I have just checked the Ecu looking for the codes and it appears to be dead (the Ecu led doesn't glow when I turn they key on)
I have cleaned the ptu connectors with electric cleaner.
I've checked all the fuses, switched the relays, disconnect the alarm system, and it still not starting!

[magalehz32]

And yah, I've checked for sparks from the spark plug and there is nothing....I've even touched it with my bear hands

[magalehz32]

my PTU is the new one,, I think its the s2. anyway its the black one not the silver.

[Ace2cool]

Ouch, if you're not getting a light on the ECU, that doesn't sound good. Try reseating the ECU connector, and if that doesn't work, try to find one for troubleshooting. Where are you located?

[magalehz32]

I unpluged the Ecu connector and then plug it again and I am still not getting anything?! Does that mean that I have a bad ECU? and what could burn an ECU? I am really confused
I am in San Francisco, CA. I already took it to a mechanic, and he gave up! the nearest Z specialist is 50 miles a way, my car parked in the street and I still have till Monday till they tow my car a way.... I hate sfmta they are money suckers...

[magalehz32]

I am thinking of throwing another ECU in it, since the mechanic mentioned something about the ECU, does all the N/A Zs have the same ECU from 1990-95?

[BlackWidowZ]

yes. NA Z32 ecu up to 95 is the same. 96 is obdII and wont work. The TT ECU is different and wont work.

Check this out here you might have an electrical problem that tripped the security system.

Try this 1st
Also apparently you said you disconnected the alarm system...Well I read that that simply disconnecting it doesn't reset the security system. I think your car is in security mode where the car thinks its stolen and as long as it is in saftey mode there will be no power to the ECU which is one of your problems.

also apparently if the factory system is not disabled correctly and an aftermarket system is installed incorrectly. It has the possibility of telling the ECU there are 2 alarms on the system and will cause similar problems.

If the security system light is on when the doors are shut that is your culprit. It always blinks when they are open,

Code: Select all

To reset the theft system on a 1993 Nissan 300ZX, you must disarm it. If you do not have the keyless entry remote, you can manually disarm the alarm. Slide the key to the 300ZX into the lock cylinder on either front door. Turn the key toward the front of the car. Return the key to the upright position and remove it from the lock. 

Then try this.
http://www.zdriver.com/forum/300zx-z32- ... tem-14941/

Excerpt...

Code: Select all

i didn't know i had this, but behind the board/interior body panel that is like in front of the driver's knees...right under the steering wheel...there's a little black box with a switch that i guess is the main power switch for this gay security system...and i also guess that if this security system is tripped or set off, it causes the car to go into some safety mode where it will not provide power to the ECU, not allowing it to run, i guess to keep it from getting stolen or something...

we reset that by just like playing with the switch a few times, and the car fired right up...drove it a bit, was fine....parked it...turned it off, then it turned right back on when i tried...

[youtube]http://www.youtube.com/watch?v=bo5bkaywFqw[/youtube]

if none of that works try this
http://en.allexperts.com/q/Nissan-Repai ... system.htm

[magalehz32]

The security light stays on if the doors are locked, and it flashes when the doors are unlocked.
I am going to try reset it tomorrow, it seems that it has something to do with the alarm system as I had previous problems with it( it goes off by itself sometimes without even touching the car!).....One BaD SecuiRty System .....

[BlackWidowZ]

The security light stays on if the doors are locked, and it flashes when the doors are unlocked.
I am going to try reset it tomorrow, it seems that it has something to do with the alarm system as I had previous problems with it( it goes off by itself sometimes without even touching the car!).....One BaD SecuiRty System .....

yup your car is in security mode and has disabled power to the ECU. The nissan security system is wired to the ECU, also aftermarket is wired to ECU. So when the car get locked in security mode the ecu is disabled.

[magalehz32]

Hmmmmm, Thanks . I am going to start with that tomorrow....Peace

[magalehz32]

Update: 1. I reconnected the security system and reset it using the key on the driver side door lock, and it looks like it was reseting (the security light on the dash was glowing when its look, stops when its unlocked) but still nothing the car won't start.
2.I have looked for a black box that has switch in front of the driver knees (as a previous post in the forum says) but my z doesn't have one, because it appeared to be an aftermarket security system!!
3. I finally decided to buy another ECU, bought one, installed it, and the LED of the new ECU doesn't glow when I turn the key to the on position...

Still nothing, but thanks god I got some help and pushed my car across the street so SFMTA will not tow my car, but that will give me only another 72 hours. parking in SF sucks!!!

[Ace2cool]

Ohhhhhh, it's an aftermarket system. Crap. That just makes it a million times harder. Could be a blown fuse on the aftermarket system. Most systems will tap into the ECU power, since that's the best "killswitch" you're gonna find. No spark or fuel.

[magalehz32]

No actually I have the original security system, I don't have an aftermarket security system. I was talking about this post:
http://www.zdriver.com/forum/300zx-z32- ... tem-14941/

in which the poster didn't know that he had an aftermarket security system which mislead me.....Too much explaining....

[Ace2cool]

Oh, ok, cool. Well, at this point, the only other thing I can think of is to read wires. Here's a pinout. You ever used a multimeter before?



The main ones I'd check are the ones that say Power to positive with the key on, and from ground to a chassis ground.

You did check all your fuses and fusible links, right?

[magalehz32]

Yes, I have used a multimeter before. and I have checked the fuses next to the drivers left foot, and the ones under the hood on the diver side(fuse box). is there any other fuses that I don't know about?
Thanks for your reply...

[Ace2cool]

The fusible links are on the passenger side by the battery. That's all I can really think to check.

[ruslan300]

The light on ecu is hard to see some times, so if you switch it to the test mode with ignition on the check engine light on dash will blink just like the light on the ecu would. If it does blink Your ecu should be fine. My z died once on me like that just out of no where and it was the connecter to the CAS. it was missing the clip that holds it in place and it slightly unplugged and wouldn't start. You can also unscrew the CAS and turn on ignition. Spin the CAS and if it works you will hear injectors firing and there should be a spark also. If not then its a bad CAS.

[magalehz32]

Update: finally I got my car fixed at a mechanic. the problem was a relay that controls the ECU and two shorts in the wires underneath the fuse box. that's what the mechanic said!