Since this has happened I have tried to 're do the TPS that actually does nothing now :( no change in engine idle

 

 

Do you have access to conzult or datascan or anything?

Pulled 34 det sensor and 21 ignition circuit sensor .....

I have spent the last 4 hours checking every plug and connector. cleaned and plugged back in, I removed all spark plugs all are clean and oil free. checked all vac hoses for leaks as well. I re done the TPS and tried the Idle control valve ( which doesn't do a thing when I turn the screw) ??? removed the PTC cleaned it and re fitted it. unplugged MAF while running and car stalls so that's working at least. one thing I did notice today was the while I was trying to do the TPS reading the RPM was at about 500 or less and the engine was struggling to idle and kept stalling a few times, once it started again there is this funny buzzing from the rear of the engine and also a lot of ticking clicking coming from the rear of the plenum? also later this evening I have noticed the battery light is on very dim while the car is running.... checked connections and all terminals are tight. this is driving me mad ;( my know how of engines is a bit limited. but I have tried everything I can think of.

Pulled 34 det sensor and 21 ignition circuit sensor .....

i have spent the last 4 hours checking every plug and connector. Cleaned and plugged back in, i removed all spark plugs all are clean and oil free. Checked all vac hoses for leaks as well. I re done the tps and tried the idle control valve ( which doesn't do a thing when i turn the screw) ??? Removed the ptc cleaned it and re fitted it. Unplugged maf while running and car stalls so that's working at least. One thing i did notice today was the while i was trying to do the tps reading the rpm was at about 500 or less and the engine was struggling to idle and kept stalling a few times, once it started again there is this funny buzzing from the rear of the engine and also a lot of ticking clicking coming from the rear of the plenum? Also later this evening i have noticed the battery light is on very dim while the car is running.... Checked connections and all terminals are tight. This is driving me mad ;( my know how of engines is a bit limited. But i have tried everything i can think of.

 

ptu not ptc

Pulled 34 det sensor and 21 ignition circuit sensor .....

 

Code #34 Detonation Sensor - won't have an effect on the engine idle.

 

Code #21 Ignition Signal - will affect idle & drivability.

 

The things to check relate to the Power Transistor Unit (PTU), wiring & connections.

Diagnostic Procedure 27 relating to Code No.21 can be found in the EF & EC Section in the NISSAN Factory Service Manual.

Thanks Twin Turbo. will check it, may check the idle air control valve also.

Worth a read http://www.twinturbo.net/nissan/300zx/forums/technical/view/1106815/Is-this-CODE-21-WRITE-UP-tech-article-worthy-IMG-help-plz.html

Ok so I've spent all day today going through that list groover kindly put on here. Checked all Voltages from coil plugs all around the 12 v ... Checked ptu voltage and earth came up fine. 're checked all engine earth points and cleaned. 're fitted new battery terminals replaced all coil plugs with new .. Checked battery voltage while running 14.2 v took off the iaacv as it wasn't doing anything when I turn the screw. Cleaned it all and cleaned springs inside. Placed back with new hoses x2 and cleaned the plugs on it was well. Checked fuse box engine com under ignition was blown replaced that. Car now does not give ecu error 21. However still pulls code 34. Det sensor.

 

Cars idle is a bit better around the 750 mk is there any way to adjust this as the iaacv does not work shall.I just buy a new one? Maybe the solinoide has gone tits up?

Further to that ecu now reads 55 so all ok apart from the rough ish idle

The idle is fine now, obviously still rough, which would suggest something else, have you ohm'ed your injectors? the next big cause of misfire, also temp sender.

Idle air is probably fighting with the ecu to stay stable due to another fault, it may not be the iacv itself at fault.

 

I had an injector down and my iacv would not adjust either, till i sorted the problem, then it worked.

Hi groover I only ohm'ed the coil plugs and the coils... Not tried the injectors Do you not have to dremmel the buggers out? Or Is there another way? From ecu maybe...

You don't need to dremel the plenum to test the resistance of the injectors, just unplug and read, the dremel comes out if you want to change an injector without removing the plenum.

Thanks guys your help has been overwhelmimg :)

Each injector should read between 10-14ohms anything over that or no reading and they are toast, easiest way to remove the clip on the injector plug is a largish flat blade screwdriver under the rear of the plug, ie from inside plenum legs, so throttle cover removed, and prise up. The clip will open allowing the plug to be pulled, just take it easy and have a magnet at the ready to catch a pinging clip lol

 

http://www.300zx.co.uk/forums/showthread.php?147148-Sensors-and-voltages

 

 

Edited July 16, 201510 yr by groover

Great thanks groover I'll have a go tomorrow :)

I had a failed injector last year!

Put a long screw driver on each injector with the engine running & u will hear the injector ticking away.

If it does not tick the injector is faulty!

Have u not done this yet?

Art

The only problem with that little test is that you will here other ticking along the length of fuel rail, as it will echo and it can be mistaken for an audible tick but not a guarantee its the one your are listening too.

Ok Will have a go in an hour or so I've just got in her to start started ok but rough and running on 5 cylinders again and I'm even fighting with the throttle to keep her running having to press right down and the revs are still dropping splutering ect mmmmm

To add, when i say prise up using the screwdriver, i mean place the flat part of blade under plug, then rotate, so as the blade turns up it lifts the plug, not used like a jemmy bar lol

I got 3 off and tested all started at around 13/14 ohms then went nuts reading from 19 up to 80 odd thats all 3

The reading should be a constant, make sure you use the right terminals, ie swap the probes around

Yeah I have I'm.just about to buy a new battery for the meter just to make sure.

How are the injector terminals looking, any green corrosion on them?

They look good in fact I think they have been replaced at some point as the plugs are light blue??..unless that's the oem colour?