Hi all,

Bought '91 Z32 manual TT in Sept 20. Ran fine for a while until check engine light came on while driving, mechanical whirring sound, clicky/zappy sounds from somewhere around driver's side, high-idle and jerky power-delivery. Now barely idles and just dies. It's been through two diagnostics that didn't flag anything. I was aware that it ran slightly rich when I got it but it seems to have got worse to the point of non-starting. Are there any Z or JDM specialists in Essex or SE that anyone is aware of. My 20 year old dream is becoming a bit of a 30 year old nightmare! All help/advice is appreciated. Thank you so much.

Welcome... shame about the circumstances of your first post! First thing, stop trying to run it... not worth risking more damage; you'll need to get it diagnosed with proper diagnostics, rather than generic OBD - if your post you location, you might be lucky and find someone that can plug it in for you before going to the expense of getting it to a specialist. Good luck! 

Edited April 12, 20214 yr by Rich666

23 minutes ago, Rich666 said:

Welcome... shame about the circumstances of your first post! First thing, stop trying to run it... not worth risking more damage; you'll need to get it diagnosed with proper diagnostics, rather than generic OBD - if your post you location, you might be lucky and find someone that can plug it in for you before going to the expense of getting it to a specialist. Good luck! 

Thank you so much for getting back to me so quickly! Yes 100% keys staying firmly out of the ignition! I'm located in sunny Southend on Sea, Essex ? I've had a crawl around the internet and a video affirmed my suspicion that it's a faulty MAF sensor so I'm ordering a new one in the meantime but without an accurate OBD it's still a shot in the dark, couldn't hurt to replace though just in case? Or not something to be fiddled with if not necessary?

7 minutes ago, 300Zach said:

Thank you so much for getting back to me so quickly! Yes 100% keys staying firmly out of the ignition! I'm located in sunny Southend on Sea, Essex ? I've had a crawl around the internet and a video affirmed my suspicion that it's a faulty MAF sensor so I'm ordering a new one in the meantime but without an accurate OBD it's still a shot in the dark, couldn't hurt to replace though just in case? Or not something to be fiddled with if not necessary?

Haha good! 

Def get the codes read before fitting the MAF and trying to start it again though - it wouldn't cause all of those symptoms, in fact the car will run ok with the MAF disconnected, jut wont rev far. Fingers crossed for you! 

51 minutes ago, Rich666 said:

Haha good! 

Def get the codes read before fitting the MAF and trying to start it again though - it wouldn't cause all of those symptoms, in fact the car will run ok with the MAF disconnected, jut wont rev far. Fingers crossed for you! 

Will do! On the hunt for diagnostic wizards now. I'll update in future posts. Again, thank you so much ?

Welcome to the club Zach and hope its a good quality maf you have bought. 

15 hours ago, 300Zach said:

Will do! On the hunt for diagnostic wizards now. I'll update in future posts. Again, thank you so much ?

Had a thought, you can do a basic check of codes manually - the link below has instructions, but I wouldn't run the engine-running checks until you know what's causing the unusual sounds... those asterisked are the ones that will throw a check engine light:

http://www.ttzd.com/tech/diagnostictech.html

It's been that long since I have done any work on a 300, I totally forgot! 

1 hour ago, Rich666 said:

Had a thought, you can do a basic check of codes manually - the link below has instructions, but I wouldn't run the engine-running checks until you know what's causing the unusual sounds... those asterisked are the ones that will throw a check engine light:

http://www.ttzd.com/tech/diagnostictech.html

It's been that long since I have done any work on a 300, I totally forgot! 

You're a ledge! Thank you I'll have a look and get my checklist out ? 

This guide is a little more comprehensive re fault codes:

http://www.twinturbo.net/nissan/300zx/forums/technical/view/1105629/The-Ultimate-Guide-to-ECU-Diagnostics.html

6 hours ago, AndrewG said:

This guide is a little more comprehensive re fault codes:

http://www.twinturbo.net/nissan/300zx/forums/technical/view/1105629/The-Ultimate-Guide-to-ECU-Diagnostics.html

Thank you! I'll look over it right away, was just about to reply to Rich, the internal code-checker flagged a "34" with the engine not started, apparently corresponds to the detonation sensor so going to have a read up on that too

8 hours ago, 300Zach said:

You're a ledge! Thank you I'll have a look and get my checklist out ? 

So on your advice I got it open and with the engine off it flagged code "34" detonation sensor, not one of the asterisk ones that triggers a mode 1 check engine light but going to continue to dig deeper in the meantime

Code 34 can be solved (temporarily) by putting a resistor across the contacts in the det sensor plug. The det sensor is on the back of the engine and quite a faff to get to, hence the temp fix until you can get to the sensor. I cant remember the exact resistance of the resistor though... give it a google and it should tell you.

Details in guide above, detonation sensor bypass uses a 1MΩ resistor. You will need to erase ECU fault code(s)

after inserting resistor.

FSM diagnostics (there may be a harness/plug fault between sensor and ECU).

efec 133.pdf

 

 

On 12/04/2021 at 20:02, Gaz 300 said:

Welcome to the club Zach and hope its a good quality maf you have bought. 

Yup - welcome indeed Zach.....

....And just as Gary says, don't waste your money on the cheap Chinese copies - I'd buy a known working 2nd hand OEM one over a pattern copy!

If you need specialist ZX-help, you can't go wrong with Jimmer in Bristol - he's the go-to Z mechanic, not just in the UK, but Europe too. 

16 hours ago, RichardS said:

Yup - welcome indeed Zach.....

....And just as Gary says, don't waste your money on the cheap Chinese copies - I'd buy a known working 2nd hand OEM one over a pattern copy!

If you need specialist ZX-help, you can't go wrong with Jimmer in Bristol - he's the go-to Z mechanic, not just in the UK, but Europe too. 

Thank you! The warm welcome is really appreciated and all the advice is so kind! I've invested in an OEM MAF sensor from Concept Z and a 2nd hand OEM Det/Knock from ebay. Need to save some dosh but next Tuesday I'm going to buy a license for Conzult on the advice of some of the chaps kindly posting their wisdom here, I'm hoping that'll show me the running-codes without having to risk any damage with a start-up. Today I've had the air filter/MAF out, connector looks fine. I have an after-market electric fan which doesn't appear to have any damage or degradation to connectors/relays so prayers are a simple MAF replacement.

I've seen Jimmer mentioned all over and his reputation sounds like it proceeds him! Does he have a website or do I have to write a letter with recommendations? ?

On 15/04/2021 at 06:36, TheRealNips said:

Code 34 can be solved (temporarily) by putting a resistor across the contacts in the det sensor plug. The det sensor is on the back of the engine and quite a faff to get to, hence the temp fix until you can get to the sensor. I cant remember the exact resistance of the resistor though... give it a google and it should tell you.

Thank you! I got a current checker as well so I'll definitely be keeping this cheeky-quick-fix as a contingency if I have to drive it to get things sorted elsewhere ? I have a second-hand det/knock sensor on the way but truth be told it looks like a real fiddle to do and I quickly felt intimidated ?

On 12/04/2021 at 20:02, Gaz 300 said:

Welcome to the club Zach and hope its a good quality maf you have bought. 

Thank you, really can't get over this amazingly warm-welcome from everybody. Got an OEM one. Only the best for our babies right? ??

On 15/04/2021 at 12:14, AndrewG said:

Details in guide above, detonation sensor bypass uses a 1MΩ resistor. You will need to erase ECU fault code(s)

after inserting resistor.

FSM diagnostics (there may be a harness/plug fault between sensor and ECU).

efec 133.pdf 414.91 kB · 3 downloads

 

 

Thanks AndrewG! I'll pop down the hardware store and pick one up. I do have a det/knock sensor on the way but I really appreciate the guide and I'll be using it as a contingency because replacing the whole sensor does admittedly look pretty intimidating ?

When my detonation sensor went my Z just ran in safe mode it wasn’t running rough or anything like that. Was a right faff to change. 

6 hours ago, dipone said:

When my detonation sensor went my Z just ran in safe mode it wasn’t running rough or anything like that. Was a right faff to change. 

Yeah man it definitely looks faffy!

What does "safe mode" feel like exactly? Or are there any cockpit-indicators that it's doing so? I detailed the symptoms in my initial post and I think the Det/knock is only one thing. I'm hoping with conzult I'll know what else is causing the more intense troubles I described back there since according to the read-out the code 34 for det/knock won't cause the CEL to come on in mode 1. It's all a big detective game isn't it! ?

https://conceptzperformance.com/wiki/index.php/Safety_Mode

On 16/04/2021 at 14:05, 300Zach said:

...................I've seen Jimmer mentioned all over and his reputation sounds like it proceeds him! Does he have a website or do I have to write a letter with recommendations? ?

Powerzed - 300ZX Owners Club

Here's Jimmer's traders link - you can also find him on Facebook and his own website:

PowerZed | Nissan 300 350 370 ZX Site and Forum

13 hours ago, AndrewG said:

https://conceptzperformance.com/wiki/index.php/Safety_Mode

God these cars are far smarter than I ever knew! That limp-home mode sounds very reminiscent of what mine is doing too... very sus. Praying it's a faulty MAF because that's not such a chore to fix ? thank you for this Andrew, concept Z really is a gold-mine for more than just parts!

12 hours ago, RichardS said:

Powerzed - 300ZX Owners Club

Here's Jimmer's traders link - you can also find him on Facebook and his own website:

PowerZed | Nissan 300 350 370 ZX Site and Forum

Thank you! I'll be signing up for premium on payday for sure! Bristol is such a great city. Perfect excuse to do some travel ? This is all so great, wish I could convey how much I value everyone's help and input! 

Hope you get sorted... I'm in the early stages of re-commissioning mine and I am dreading the day I come to try and start it - engine's not run in 15 years! (Just to add, I'm not just planning on fitting a battery and hoping for the best!)

12 hours ago, Rich666 said:

Hope you get sorted... I'm in the early stages of re-commissioning mine and I am dreading the day I come to try and start it - engine's not run in 15 years! (Just to add, I'm not just planning on fitting a battery and hoping for the best!)

??? I'll definitely post a picture when it's up and running (so you can all say "Oh no you bought *that* one" ?).

15 years!? That's not a restart, that's a resurrection ? definitely going to want more than a battery. Maybe a priest to bless it! Where would you even start with something like that?