JEDI-77

Hi guys, I'm from Australia, but hoping you can help..:) Ok this is weird so please bare with me while I explain.. The zed (1990 NA, 5 Speed) has developed a very annoying electrical problem, this is what it does: Drive the zed around and all is fine. All of a sudden I will start to hear a whine coming through the car, that rises or decreases based on the revs of the engine. This whine will come and go but will always be present for the rest of the drive. Then, when I finally come to a stop and switch the car off, I lose all power. As if someone has taken the battery out of the car. No alarm ( I cant arm or disarm the car, and no flashing LED), no interior lighting, no ignition, no head lights. The power is just completely gone, like I said, as if someone has walked away with the battery. And then I wait. All of a sudden, anywhere from 1 minute on wards all of a sudden all the power comes back (why this delay in time?? Does something need to cool down?). My alarm starts working, the LEDs flash, the interior light comes on and I can start the car. When the power comes back, the clock has reset itself and the climate control has gone back to 25 degree's celcius, the default position as what happens when you disconnect and then reconnect the battery. This weird electrical issue only happens on long drives (say 20min +). A short trip down the road and back, and everything is fine. Ok so, anyone have any ideas on where I can start trouble shooting?? This is what I have done so far: 1) Checked all stereo wiring. Because the first sign of something being wrong is the alternator whine coming through the stereo, I have checked and double checked all the stereo wiring. Everything is fine. Also, the stereo wiring has not been touched for ages so it is odd that something would be wrong now. And the stereo would not be responsible for the total power black out. 2) While driving, the electrical system is fine. The volts are between 13.5 - 14 (I have a volt meter installed) and the battery holds charge, and the car starts at the turn of the key (when the funny power blackout thing isn't happening). 3) Fuses. Don't know where to start here. In my mind a fuse would either be blown or be ok. Whereas this seems to be intermittent, as if something needs to cool down and then all power comes back. Any fuses I should check? 4) Alternator. The alternator is new, bought from Coz (ConceptZ, U.S) earlier on in the year. I have no reason to think that it is at fault. However, since installing it, I do remember my car having some odd electrical problems in the past on 2 separate occasions. I was able to start the car on those two occasions, but did notice that the clock and climate control had reset itself. At the time I thought what the hell?, but I brushed it off and thought nothing of it. Now, since its been warm here in Aus, it does it every time I drive the car (long drive). Any help would be much appreciated so I can find this electrical gremlin hiding in my car. Many thanks

Hi to all, I'm from the Australian 300zx club (http://www.aus300zx.com), and that episode of Top Gear has also caused quite a stir on our forum. Good to finally see a Z32 on top gear and performing as well as we all know they can..:)

I have a 1990 non-turbo 300zx. A few years back I had some extractors installed and at the time of installation the EGR was removed (the extractors did not accommodate the EGR). Since then, the car has suffered some light detonation at light throttle or cruise conditions in hot ambient temperatures (more so when the aircon is on, I assume because the aircon puts an extra load on the engine). The exact same spot where the EGR is normally active. Now, I have spent the last couple of years checking everything on the car (fuel pressure, fuel flow, spark plugs, compression….. everything that can cause detonation) and everything is fine. So it seems that the detonation is caused by the high temperature of the incoming air, and since the cooling effects of the EGR are no longer present, this allows detonation to occur. I only use 98 octane fuel (the highest we have in australia is 100 octane, but that contains ethanol), but the detonation still persists. If I use a bottle of octane booster, the detonation is gone. Using Nissan Datascan I have been able to track at exactly what location in the timing and fuel map the detonation occurs. In the fuel map, it is in the closed loop section, between 2000-3000 rpm, light load, where the A/F ratio’s are quite lean. In the timing map, the detonation occurs at an area where the ignition timing is quite high (42 degree’s). I have been able to combat this problem to a degree by reducing the ignition timing in that area to about 37 degrees (5 degree retard). However, on really hot days (35 celcius +) the pinging is still there. Very feint, but quite noticeable if driving past a wall or barrier where the engine noises are reflected back. More so if traveling up hill. And using the aircon on these days is just impossible as that makes the pinging much worse and very noticeable. I am reluctant to take out more timing in that area as it may affect the driveability of the car. I haven’t noticed any difference between having the ignition timing at 37 degrees compared to 42 degrees, but was wondering what would be the safest and lowest that I could go with the timing in those light throttle / cruise areas? Also, I am planning to add more fuel to the effected areas to try and cool the combustion chamber. I will need to convert those cells from closed loop to open loop, and increase the A/F ratio from 14.7:1 to maybe 13:1??? Is that too excessive?? I know this will effect my fuel economy, but I don’t mind as I have a device which enables me to alternate between 2 separate ECU tunes. So I would only use the “non-economical” tune on hot days. Once again, is there a limit as to how much fuel I should add in this area?? If anyone has any advice or suggestions to helping me tune out the detonation, or see a problem with what I have listed above, please let me know. Thanks

I wasnt aware that retarding the timing increased the EGT. Still, it does remove my pinging by retarding the timing a few degree's in hot weather. In regards to adding more fuel in those low area's, wont the O2 sensors compensate for the extra fuel by leaning out the mix even more? Cheers

I use 98 RON fuel which here in australia is our high octane fuel. We also have 100 Ron fuel but it contains ethanol so us zedders avoid using it... But yes, my car will still ping on hot days with 98 RON fuel. Whats more annoying is that I am using an aus-spec ecu which is designed to run with 91 RON fuel. However, I still have to retard the timing a little to eliminate the pinging. This makes the car fine to drive with the aircon on, except for very hot days (33 degree's +). Funny thing is, with the aircon off, I can drive around in extreme heat no problems. Cheers

Hi guys, just a quick hello from Australia..:) I lurk around here from time to time but my home forum is http://www.aus300zx.com... Anyway, I'm after some peoples views on a problem I am having, one that I think is linked to the EGR. Having read a few 300zx forums over the years, it seems quite common to remove the EGR when the engine is out. It cleans up the engine bay and avoids some nasty problems if its not working properley. However, this recommendation seems to always be for TT's, but being an NA owner myself I'm starting to believe that the EGR removal is not a wise move for the NA. I want some of you tech guys to tell me if i'm wrong or right. Now, my car suffers from light / part throttle detonation on hot days and having the aircon on. I can easily accelerate through it, and there is no detonation at WOT, even on a 40 degree day as proved on a dyno. It has already cost me one motor a few years back (cylinder 6 dropped down to 100psi and was burning oil) and unfortuneatly the nasty ping gremlin has also carried over onto my 2nd motor. The only link between the 2 motors is that in both occasions, the motors have run without an EGR as it was removed many years ago. Over the years, I have replaced all (and I mean all) my engine sensors, fuel pump, injectors, fuel regulator, dampner, checked fuel pressure, CAS, MAF, played with timing, ran with colder plugs.... etc etc.... everything you could possibly do to counter act pinging.... but on really hot days, the pinging remains... The only way I have been able to deal with it is to retard the timing a little, and also have an aftermarket piggy back computer installed (UniChip) with which I can take out some timing in the light throttle area's... So after all this, I regret having removed my EGR which was removed when I had my Headers / Exractors installed which did not have a fitting for the EGR plumbing. And since then, all the plumbing and solenoids have been removed so trying to put the system back in would be a nightmare. My theory is that since the NA runs a higher compression ratio under cruise conditions (10:1 compared to 8:1 on a TT off boost), the high ambient temps make the NA more prone to detonation under these light throttle conditions where the timing is quite advanced (around 35-40 degree's on my manual NA), and the A/F ratio is lean as the O2 sensors try to maintain a 14:1 A/F ratio... Its at these light throttle conditions where the EGR is active and uses inert exhaust gases to cool down the cumbustion chambers.. So is my theory totally incorrect, or just so plain obvious that this post is a waste of time?? If so, then perhaps we should be careful with advice such as removing the EGR as although it may be fine for the TT, it may be detrimental for the NA. Cheers