This has happened intermittently for a while, basically the fuel pump makes a slightly higher pitched whining noise than normal, engine cranks but no joy. Then sometimes it fires normally, very odd and I heard it might be the PTU so dremelled it open only to find all connections were good, cleaned the plug connections too while I was at it, still the same. Any thoughts guys?

If the fuel pump is louder and maybe higher pitch? The pump could be on its way out? Maybe.

tbh it could just be me hearing things but theres fuel going in, flooded it more than once trying to get it to start

Could still be the PTU I don't think it's the pump, especially if you flooded it more than once, try another PTU.

Hi,

one of the common issues with the Z starting or running bad is the temp sender unit (not the gauge one, the one that sends to the ecu).

 

you can test it by using a Conzult or Ohm meter.. try unplugging it and see if that makes a difference.

 

you can't go wrong by checking and cleaning every connector you can find... and this is a very good guide:

 

http://www.twinturbo.net/nissan/300zx/forums/technical/view/922678/The-6-Ps-Proper-Preparation-Prevents-Piss-Poor-Performancegt.html

 

 

best of luck.

Cheers for the tips guys, no other PTU to hand to try, really want to make sure it is that thats at fault before I buy another tbh. Temp sender unit? Hmm, worth a look, especially as very recently the temp gauge stopped working too.

 

Tonight however raised more issues, fully charged battery, turned key, clunk, all power gone, no dash lights, no nothing. Jump leads on, dash lights, turn key, clunk, nothing again!

Hmm. If it is doing nothing at all then sounds like it is the ptu.

Is it cranking at all? You said it was previously.

I had a problem with my ptu where the wires had dropped down and rubbed on the fan belt. This made wires arch over and cause many issues haha. Check the wiring also on the ptu and coil pack connectors... the fact it isn't doing anything.... no crank. Check battery. If it doesn't do it with jump leads I'm not too sure. Let charge for a bit?

Cheers for the tips guys, no other PTU to hand to try, really want to make sure it is that thats at fault before I buy another tbh. Temp sender unit? Hmm, worth a look, especially as very recently the temp gauge stopped working too.

 

Tonight however raised more issues, fully charged battery, turned key, clunk, all power gone, no dash lights, no nothing. Jump leads on, dash lights, turn key, clunk, nothing again!

 

Battery connection, remove clean refit, also check earth.

 

Jeff

long shot but if the car is alarmed it maybe the alarm immobiliser circuits failed or playing up

It was indeed the battery connection, damn wires at the end were shot, trimmed em back and re-ended em made it fire again, still back to the other problem though, it will start, run for a bit, then cut out, attempting to start it again, fuel pump makes a high pitched noise for about a second and half, then just cranks and cranks. PTU btw is ice cold during all this

Hi,

 

not sure if you know this but.... once you flood a 300zx they are a bitch to start... so be very careful (there are posts on how to resolve if it floods).

 

secondly i should have been clear about the temp sender unit ... there are two of them, one send temp signals to the gauge (only) and the other one to the ecu for the cars running.

 

So the second one is much more important to the running of the car and often go wrong, try unplugging it and see what happens (its the 2 prog unit).

 

have you done a full PM on all the wires connectors, fuses, and hoses?

Wires and fuses all checked, hoses are good. Location of the temp sender, up front near the fan?

yes the orange one (with the two pronged connector) - coolant temp sensor

Checked it today and it was covered in crud and what looked like gasket sealer when i took it out, cleaned it all up and went to put it back only to find the connector wouldnt fasten properly as bits had broken off, then I noticed a wire off, black so prob earth. Where can i get another connector from?[/img]

Those connections look like AiV and EGR.

from the UK..

 

http://www.zcentre.co.uk/index.php?page=shop.product_details&category_id=67&flypage=flypage.pbv.tpl&product_id=102&option=com_virtuemart&Itemid=7

 

from the USA..

 

https://conceptzperformance.com/Cart/description.php?II=683

 

 

 

just use some spade connectors for the time being....

Spade connectors on!

 

Previous owner had removed the EGR, plugs the same as the one thats broke (you know whats coming), ok to lop that one off and use it yeah?

I'd say yes it you can confirm its the same... some have slight variations ... best to be sure (not a problem, just a waste of time).. :)

Well the problem hasnt come back since putting the spades on, very tight fit and they are well insulated so may well leave it at that tbh. Anyway, slightly off topic but does anyone know what this red switch is supposed to do? Its "something" to do with the lights but doesnt appear to do anything at all, apart from light up. Guy had aftermarket Xenons fitted (which are rubbish btw), might be something to do with those perhaps?

LOL.. no idea, its not OEM... he must have fitted that himself..

 

there are a lot of fused for the lights, not only in the foot well but also in the engine bay..

 

the original 300zx lights are crap, you are better off putting in some HIDs since it already had a projector lens..

 

have a look in the tech section ... really worth doing..

these are a couple of guides and different levels of modification..

 

http://www.300zx.co.uk/forums/showthread.php?132852-HiD-install&highlight=HID

 

and

 

http://www.300zx.co.uk/forums/showthread.php?117007-HID-light-mod&highlight=HID

 

 

and these have been recommended by our lights mod guru ..

 

http://www.ebay.co.uk/itm/SUNWOIF-55W-Car-Single-Hi-Lo-HID-Xenon-Conversion-KIT-H1-H3-H7-H8-H9-H11-H4-UK-/251684667627?pt=LH_DefaultDomain_3&var=&hash=item3a999340eb

I would guarantee this is for a rear fog light

Anyway, slightly off topic but does anyone know what this red switch is supposed to do? Its "something" to do with the lights but doesnt appear to do anything at all, apart from light up.

 

And my guess is that it doesn't even light up when your sidelights or dips are not on :no:.