JeffTT

Refit the engine and then offer up the gearbox after. Jeff

Just to clarify, why on earth would running the engine and warming the manifolds /turbo`s be a good idea when the next job is to open the fuel system close by?? Just change the filter in after an over night shut down and no pressure...simples. Jeff

Completely unnecessary, simply leaving the car overnight un-started and the majority of the pressure leaks away back into the tank, this is the very reason the fuel pump has to prime when the ignition is switched on, that said always use catch cloths and never, never change the filter on a hot engine, that exhaust manifold / turbo is inches away... Jeff

The replacement bulb kits are a pointless law on many new cars as bumpers need removing to access the headlights....cannot see the Gendarmes allowing that on the hard shoulder !

What makes you think you have an injector issue ? Jeff

So first lets deal with the wandering / twitching ignition timing, the earlier cas units did suffer from early location pin wear and could cause drifting, as could a faulty cas itself, however the later one have an issue with interference from bad shielding on the cas pick up cable, watching via the Conzult ports always often shows a twitch, the later cable looms solved this, so in essence disregard that as a red herring. The video does start with a low water temperature, I have no idea how long it had been running prior to the start of the video so could of still been in its warm up phase, if not however the temp was low and could point to an issue with the stat not closing fully ( common failure, many of my tech threads show this) The injector dwell is too high at the start even with the lower temperature and would normally point to an issue with the afm, however we will see later this is not the case. The 02 sensors are both toast, one worse than the other, the external structure is likely intact but the internal pre-heat circuits which are used as a reference calibration have failed / failing completely in one and the other is on its way, this can be seen as it comes to life when the throttle is stabbed hard and it warms up, disconnecting them is usually better than leaving them connected, the results may not be seen though whilst other faults exist as we will see. The screen shot unfortunately does not show the tps hard close switch, this is essentially is the main way the ecu knows the throttle is closed fully, any issue with this can cause timing issues and stumbling, but as I cannot see it I cannot comments on it. So the throttle position sensor you mention is at its lowest, any lower and the engine cuts too easily, so, you need to check the throttle balance, sounds like one throttle is slightly ahead of the other and that been the one the tps is connected too, I did a tech thread on how to check and adjust the throttle balance, this I cannot stress is of vital importance through the whole rev range to be correct, and they do change over time as the landing pad for the throttle stops wears, and of course after any adjustments to the the throttles the tps will need resetting. See my throttle balance tech for this here >> https://www.300zx.co.uk/forums/showthread.php?151304-Throttle-balance-tech&highlight=throttle+balance So to the very obvious fault of the auxillary air valve is wide open 90% of the time, this is as the name suggests a valve that meters changing amounts of air passed in addition to the throttle butterfly`s, its primary role is to stabilise the engine when the the throttle is snapped shut, when braking, when coming to a stop and when the car is put into D on auto`s and engine drag occurs, this works in conjunction with the tps and the ignition timing. So to explain, the engine tick over speed is also regulated by the aiv, when the engine is fully warmed up, with no air leaks and timing correct you should have something like this>>>> Tick over speed around 800 rpm ( not the 750+minus 50 as in the manual, that was for a brand new engine ) Coolant temp 80c Timing 15 deg Engine speed 800 rpm Aux valve 15 % TPS 0.46V Inj time 2.2 / 2.8 Maf 1.5 to 1.8 NGK spark plugs fitted So your clearly not achieving these figures and the problem seems to be centred around incorrect air balance, and the afm issue is the first that needs addressing. The aav been wide open is the ecu attempt to balance the engine, however the unit is failing to operate as it would be racing away if it was really open 90 % The know issues with the unit is bad connector connection and also to get jammed, in lesser cases it fails and needs replacing. To start with, check the top yellow connector, it often goes green and will need cleaning, next and to prove the point to see if it is jammed, whilst ticking over and observing the afm value, strike the unit firmly with the wooden handle of a hammer or similar, ( yeh really ) make a good few blows and see if the value changes as do the rpm. If nether of those work, disconnect the connector and apply a 12volts supply to the unit, it should of course open wide and the revs rise to a fast race. Finally if nothing, then it would be fair to assume the unit has failed. Note: on some very odd occasions it has been observed the output from the ecu to the aav has failed at board level in the ecu and this will need replacing. So moving on, lets assume you now have a working aav, good throttle balance setting and good tps setting,new 02 sensors ( or old ones disconnected ..same thing for testing) now the whole procedure needs doing again to see what figures your getting. Jeff Boost / air leak testing https://www.300zx.co.uk/forums/showthread.php?154761-Odd-boost-leak-tech&highlight=AAV Useful external links http://twinturbo.net/nissan/300zx/tech/iaa/iaa.html

Ok here we go first with the screen shots>>

Plenty going on there to comment about, will just do some frozen screen...hang on Jeff

Blueflame Exhausts built the Mongoose systems for them, but they had a business fall out and Blue flame retained the jigs and so made them under their name from then on, Mongoose used another builder and from then the fit was poor and oval tips were used, later they fitted swivel joints at the back boxes to ease the fitment issues. So maybe try speaking with Blueflame Jeff

Good info and confirms much said above >> https://www.rac.co.uk/drive/travel/driving-abroad/top-10-tips-for-driving-through-france/

If it has been standing do not jump to too many conclusions, put some miles on it and see if it settles down, check there the oil level is not too high. Jeff

Very much a DIY job if your prepared, if your doing a water delete then you can literally have the plenum off in 30 mins. Make very sure you order you bits in advance such as gaskets and tubing and with some guidance here, some picture threads and the internet you will be ok, the two inner covers have gaskets, the two outers sit on a bed of sealant, and this is where you have to be very careful as this is the place they leak, back rear corners. Jeff https://www.300zx.co.uk/forums/showthread.php?132279-Plenum-by-pass-close-up-tech-help&highlight=plenum

Just to clarify the arc protection spray is about as good a chocolate tea pot, used it on several customers cars on their behalf when we fitted coil overs and as most of our customers returned each year for servicing, mots etc. we saw in real time that it did nothing ! your better off with normal white spray grease and clean it off periodically and reapply. Jeff

Gio, has you guy tried running the engine with the O2 sensors disconnected ? see if there is an improvement..and going back to what I suggested earlier in this thread, get some new plugs fitted, not that expensive. Jeff

Rev counter is fed a signal from the cas unit as is the ecu to trigger the coil packs and injectors, would start at the connection for the cas unit first. Jeff

Wow was that 5 years ago ? time fly`s eh? Jeff

Anyone with a tool box knows this is true

Well a seal kit would get you going for now, with time to look for a new one, here is the link to a thread I did some years back, has pictures of strip etc. Jeff https://www.300zx.co.uk/forums/showthread.php?182918-Brake-tech-thread-Thursday-!&highlight=master+cylinder

Ah damn that sounds like an over heat from lack of water, the temp guage is a mare for this, I have said many times a water level indicator warning light would be so much better, and likely easy to set up, remind me is yours turbo or na? Jeff

Get a test done like this first >>

Be aware Trev, the term head gasket failure is often an incorrect description, head gaskets, especially on the 300zx do not fail on their own, there is always a cause. Just changing the gaskets will not effect a repair on its own. So the failure of the gaskets ability to seal in the water between the head and block is usually the result of one or both heads warping, ( alloy heads on a cast block ) this could of been due to water loss, failed water pump or pin holes in the head surface. So a full water system check is required to see where the original issue started out, and then the heads will need removing ( can be done in the car easier on non turbo ) and sent away for checking and skimming if the rest of the engine is ok. The block will need a through check and the tops of the pistons and the cylinder`s condition checked and even measured for wear, of course this strip will require you do a cambelt change, even if the existing belt looks ok. New belt pulley rollers, new water pump, new tensioner and by pass hoses, then on to ancillary belts. The cost of this job in parts os not insignificant, do not be tempted to just change the gaskets, not skim the heads and fit the old belt on, this will be a recipe for disaster. Good look and and use the search button on hear, plenty of info. Jeff This is the level of stripping required, this however is a non turbo engine which is significantly easier in the car, but turbo can also be done.

:clap:

Nah that is Banter, me and Si have know each other for a very long time . Jeff

Perfect this is the normal procedure on even brand new cars whilst been serviced at dealers.

Managed to spend 5 minutes thumbing through the magazine in the airport newsagent and the major off for me and why I did not feel the urge to buy was the very low grade paper the magazine is printed on, when paying a fiver for a magazine I would rather it not remind me of school blotting paper !