Jynxeh

Yep know what you're saying, but even with the over fuelling fault the old platinums ran the car fine, the iridiums (which were brand new) couldn't start it. I know there seems to be a bit of a division on which plug is favourable but for me old platinums allowed the car to run in conditions where the new iriduims didn't. While those aren't exactly ideal operating conditions it is an interesting outcome, especially given how much brighter the spark from the iridiums was.

I'm running the old platinums. I haven't tried the iriduims since fixing the CTS but given the advice they won't be going back in. If anyone wants a cheap set of iriduims let me know! Only used once and as black as coal!

Thanks guys, I'd been reading through this http://www.twinturbo.net/nissan/300zx/tech/auxfan/auxfan.html and had come to the same conclusion! I've just been out and reseated the connector, spades were very green and now the fan is off and the car seems much happier, thanks guys! I have recently replaced the drive belts and I think I probably knocked it then. Jeff, what an I told-you-so moment. You said the same thing to me just over a year ago when you did my timing belt and I still have the piece of paper you gave me with PFR6B-11C written on it. I ordered the iridiums from a different Z specialist by mistake and got talked into using them (although he did say I could return them). Should have followed your instructions more closely! Congratulations on your retirement :) For those who might find this thread with similar problems this is interesting reading: http://www.twinturbo.net/nissan/300zx/forums/main/view/906698/Iridium-Vs-Platinum-Plugs-Answer-from-NGKs-tech-Guy.html I compared both the old platinums and the new iridiums for spark, the iridiums were MUCH better. So this issue is either the projection or down to how the different plugs react to too much fuel. Thanks again everyone for the help.

Trued to start this morning with new plugs in, caught on one cylinder but then nothing. Put old plugs back in and it started right away. Deliberately didn't change anything else, put all back as it was. Driving round OK, might still be a little rich. Thoughts? Also my electric fan is on constantly now, any idea what might have caused that?

Yeah it's a good call. I did put the old ones back in the 4 easy cylinders, didn't change anything but I should do it properly to give me a true frame of reference. Will do that first tomorrow.

Pretty happy all connection are good, and didn't move any coil pack wires far enough that they would reach another cylinder. - - - Updated - - - Oh sorry, the car is in Fareham at the moment.

Gaz, NGK BKR7EIX - the iridium plug that most seem to use for the Z. Also my car is stock, other than air filter and exhaust.

Hi, I changed the plugs on the my 91 Jap TT today and I seem to have cocked something up. I've been Googling for an hour or so now trying to make a plan for tomorrow and I'd appreciate any input from the veteran owners out there! After swapping the plugs the car ran for a while but seemed to be missing occasionally - nothing too dramatic, but worse than before. Also if I touched the throttle gently the revs would die a little before climbing (car didn't stall). I shut it off and started it a few times with no change. I shut it off and went to start it about 10 minutes later and it wouldn't start at all. Lots and lots of cranking but it didn't catch at all. Plugs were (very) wet and I checked 1 cylindrt and it did have a spark. Someone else tried to a method for trying to start a flooded car (slowly pushing the throttle to floor and then releasing it as you crank) and we managed to get the car started. Ran rough to start with an then started to clean up, still running rich. Once it was fully warmed up it started hunting, idling OK, then dropping, catching itself and returning to normal. This was happening about every 5 seconds. Rev'ed fine and seemed better at high RPM. I turned it off and disconnected the battery for 15 minutes, and it's now back to not starting - same as before. Sorry, I know that's a bit of jumbled information but hopefully someone can make sense of it! My plan for tomorrow is: - Check ECU for codes - Check for spark on all 6 (not just the 1 I did tonight) - Double check for vacuum leaks around balance bar and connections I'm guess the most likely thing I'd done is related the balance bar, I've checked all 3 o-rings and they are in place and look OK-ish. I'm wondering if I've damaged the pipe to the IACV and bits, but I'm not sure that would cause this issue - any ideas? I've checked all coil pack connectors (some were damaged) but I'm happy they are all making connections. Really would appreciate some guidance as I'm having trouble seeing the wood for the trees! Thanks, Jynx

Thanks for the info on the centre bearing, it doesn't quite seem to fit. The tyres are very worn on the inside edge due to the bad camber I mentioned previously. I'm trying to arrange to get another set to try from wchestnutt, so maybe that will shed some light.

Andrew, The prop shaft bearing does seem likely, but I'm not sure why the left turns would silence it? I've spoken to Jeff at ZedWorld and intend to replace the prop with one of his lightweight single piece ones to get rid of the problem, so maybe I should just suck it up and get that done! I guess the other option is removed the spacers on the prop bearing to raise it and see if that affects the noise at all. At least that way I might get an indication if it's related. I don't think there was anything odd in the diff oil, but I can't remember how closely I inspected it. Thanks, Jynx

Rumbley whir... There is some vibration coming through the chassis, worse at higher speeds although I think it peaks around 45-50mph. Have check p/s shoes and pads, all good. Handbrake adjustment feels good. I've taken a video with my phone on the p/s rear seat floor - not sure if it'll help at all!

Yeah I replaced the passenger side. Neither side has (had) any play or other signs of the bearing being gone. Car has done 80,000 miles btw.

Hi guys, really could do with some guidance on an issue I have at the moment. Have been Googling it a lot but so far not able to come to a firm conclusion. CAR '91 Jap Import 2+2 300zx TT ISSUE Noise coming (I believe) from the rear of the car. Noise is consistent with road speed, not engine speed. Starts around 20mph and gets louder with speed. Throttle and braking does not seem to affect the noise. Turning left makes the noise disappear instantly, it returns when you straighten up. This is either a slight left at high speeds or a sharper left at low speeds. Wheels are not noticeably warm/hot after a long drive THINGS DONE TO THE CAR I've changed the diff oil - this did not affect the noise Fitted C-cups to the rear subframe mounts - this did not affect the noise Inspected CV joints on drive shafts - no obvious issues, i.e. not split Replaced the passenger side wheel bearing - this has not affected the noise I've been reliably advised that the prop shaft bearing is gone, however I'm not convinced this fits the noise? (thoughts appreciated) Car has standard suspension but is running negative camber on the back - despite the adjuster being all the way out Any thoughts, help or similar stories appreciated! Thanks.

Not sure - could be if it's got a new owner! Was an H reg I think...

Yeah quite possibly - my Z is black, has 2 stupid hedgehog canons on the back and stock 5 spoke 16" alloys. I tried to by the yellow one to start with but was told it wasn't for sale (this was a year ago) so I went and bought my black one instead!