JeffTT

Ok new owner, done around 2k miles in it, not happy with performance or mpg, wanted a cambelt anyway so got involved with the running issue. Full Nissan service history UK zed with 60k ish miles, nice condition, when I test drove it the idle was lumpy and erratic, the performance had massive holes in the delivery of power, the turbo gauge would swing up then off and even when on boost was rubbish with bucking and sudden power ups. As I said at idle it was very lumpy and when revving would not only dip but struggle to pick up, coaxing the revs up slowly it was ok (ish) the exhaut smell was evil. So whats wrong here then?? Ok three pics, whats wrong, why is it wrong and why is the problem causing the symptoms above. Ps. No prizes for saying the plenum is missing....Jamie spotted that already:wink: Jeff TT

Completey acceptable as your using UK Ron rated fuel, an extra couple of degrees of timing advance can be beneficial with the non turbo, say 17 deg tdc, provided of course the engine is complete set up as it should be. The non C rated NGK plug is actually the stated fittment but the C rated NGK plug will work fine, not seen evidence of problems with them fitted to an N/A Jeff TT

HID ballasts are very voltage sensative, this can be often seen when HID kits are tested when a car has been sat a while and they will not work or flash like yours as the battery voltage has reduced to the working cut off point, when they strike up they use a lot of power initially. However if yours are doing this with the engine running then it could be bad connections, earths or if using the original power supply dirty relay contacts, try disconecting one and see if the other comes on and stays on. Jeff TT

Very true and seen it more than once, can cause untold damage at speed. Jeff TT

Not a Nissan belt at that price, I would make sure they have not quoted you for an ancillary belt! however if that can supply a belt for £15 - £20 ask what make and warrranty it has. Pulley is attached to the water pump, if the bearings go ( bang noise mentioned) the pulley and fan blade will flop over and strike the lower main pulley. Jeff TT

There is many variations of th ecu for the autobox, all of the below have different part numbers and have slightly different change characteristics. Ian do you have power at the ecu? 1 Twin turbo import 1990 to 1993 2 Twin turbo import 1993 to 1996 3 Twin turbo import 1996 on 4 Non turbo import 1990 to 1992 5 Non turbo import 1992 to 1994 6 Twin turbo UK 1990 to 1993 7 Twin turbo UK 1993 to 1996

OK, when I get into the office I will upload them to photobucket and send you the links. Jeff

Nice one Groover!! Jeff

Good man, pain though for you a Bank Holiday and your zed is serving a detention! Jeff

ANPR Camera`s not like the old days....beer bottle label for a tax disc and a cover note from a mate who had a photo copier..... Jeff

Yes got you one after we spoke on the phone, did you get the pics? had no reply back guessing your busy, busy. Cheers Jeff

The issue you have is dealt with in the link below, well documented and with pictures too. The actual issue is you not getting the extra by pass revs (air) when cold to go with the extra fuel and then no idle stablisation when warm, yours may not need replaceing but just cleaning or even the yellow plug is just a bad connection, either way the result is the same. Jeff TT http://www.twinturbo.net/nissan/300zx/tech/iaa/iaa.html

Did you fit a new plenum gasket? also did you reseal the outer cam covers with sealant? you don`t mention that, it is possible an error has caused an air leak, try starting the engine with the air flow meter disconnected, if its starts and runs better, then an air leak is the problem. Jeff TT

Yeh proper old school, in fact reminds me of something from my schooldays in physics class. Jeff

What is the problem that led you to want turbo`s changing, sometimes lesser smoke or power problems can be resolved in other ways. Jeff TT

From a Nissan dealership closing down, was unused when I got it. Jeff TT

Your welcome. :D Jeff

Continued... The Nissan tester unit has a series of tests you need to do in a specific order and during this a failure was detected with the pump relay, remember the original self diagnostic check said the same, this had been changed so could not be that. The Nissan tester goes a bit further though than the built in test in that abs pump can be activated from the tester but it was not responding and the display screen showed an inverted voltage across the relay contacts, the pump was disconnected electrically from the relay base and a temporary supply direct to the pump and it ran perfectly Back to the fuses and all good and supplying 12v+ to the outputs of the fuses, strange, with the pump relay removed and the ignition on the relay base contacts were checked and there appeared to be a missing live supply on the pump supply. So then it came clear a cable fault between the relay base supply fuse and the relay base existed, with a few zillion miles of cable loom to unravel it seemed more prudent to just run a new supply from the original fuse location to the pump. By running the cable through to the original fuse location we could use the original circuit breaker and so looked original and would be a long term repair, the only issue here is the fuse box cables are only accessible from below it and the supply loom is very short, by undoing the fuse box fixings and rotating it the lower cover can be removed to splice in the new cable. Once the cable was run from the fuse box to the loom at the boot abs unit a secure connection could be made there, as can be seen below, the red cable with the blue connector So a final test drive and the abs was all working perfectly again, there is no doubt the fault would have been found with out the Nissan ABS tester but as the title of the thread it really helps when you have the right tools even just as a back up. Jeff TT

The right tool for the job So we had to deal with a non turbo with an ABS fault, the system is essentially the same as the one fitted to the twin turbo so any fault finding is the same which ever model you have. The ABS system fitted to the zed has a very easy to use built in diagnosis so there is often no need for any specialist equipment. The self diagnoses is built into the abs ecu module and the ecu has a small led that flashes a set number of times to correspond to a particular fault code that is stored within the unit. A small drive is all that is required until the ABS warring light comes on and stays on, by pulling over and leaving the car running the latest fault codes can be read, the codes are limited to a maximum of 10 separate codes but then the system is relatively low tech, incidentally the most common fault by far is one of the front wheel sensors A.B.S. Fault Codes No. of Flashes Faulty 1 Left Front Actuator Solenoid Circuit 2 Right Front Actuator Solenoid Circuit 3 or 4 Rear Actuator Solenoid Circuit 5 Left Front Wheel Sensor Circuit 6 Right Front Wheel Sensor Circuit 7 or 8 Rear Wheel Sensor Circuit 9 Motor and Motor Relay 10 Solenoid Valve Relay 16 or Continuous Control Unit Dash Warning but L.E.D. Off Control Unit Power or Ground So back to the non turbo zed in question, the ABS light was on when the ignition was first tuned on and went through the normal and correct pattern of going out after the engine was started. Moving off the light came back on almost immediately which is unusual in as far as the system does not operate under 20 mph approx. so the warning light coming on so quickly was not normal at all. Initially we went for the obvious and did a built in diagnostic code check, the led light was flashing 9 times, fault 9 relates to “ pump relay contact” so it made sense to change the relay. So following the change of relay a quick test drive revealed the fault was still present , so all the fuse were checked again, the two in the small fuse panel by the brake master cylinder and one in the fuse box by the n/s headlight, all were ok. As an eliminator the ABS ecu was changed for a know good one, however the fault remained, the cables at the abs unit in the boot were checked next for condition and supply etc. With no more to go on it was time to bring the big guns out, well a genuine Nissan 300zx ABS test unit from 1990 no less. The unit requires the abs ecu to be unplugged and the unit takes the place of the ecu, from here all circuits can be check in a matter of minutes. All of the wheel sensors passed with flying colours both on resistive value and pulse output, the ecu had been changed and the fuses all were in good order and supplying power. Continue on next thread

Thought you guys might be interested in what we found with Brillomaster`s engine after its untimely failure, as you can see from the picture there is a series of nasty dents in the sump from the inside out!! that will spoil your day every time. Jeff TT

The sump plug and filter are further back than where the tray reaches to so no need to remove, there is a small access flap for the original radiator drain plug, most likely that is what your remembering. Jeff TT

There are two undertrays, the forward most one is more of an under bumper cover, I guess this the one you have fitted, the second under engine one extends from the first one under the bottom pipe area and back to the sub frame, it sound like you missing the second/main undertray Jeff TT

As others have skillfuly explained you have no need to remap when changing just an exhaust component, the mapping, chip, or eprom (choose a name) alterations are only required when raising boost due to the fueling and ignition changes. 2nd lamba ? no 2nd lamba, the zed is old school in terms of this and does not have the level of emission control that later 0B2 equiped cars have so no concerns there either. Jeff TT

Well presently concidering a deal on the whole car so, as ever everything is for sale, the engine ran before the bling was removed however I was not there so can only confirm its started and and ran, would be checking it over anyway. Will let you know in a day or so. Jeff TT

Small world or what, was talking with a mate who has a breaker yard in Birmingham and he mentioned a zed they had in so thought I take a look and surprise its an old forum zed and has a Zedworld cambelt sticker on to boot! Sure you guys will recognise it....well before the damage that is, the shiney bits had already gone from the engine...to guys here I understand, you know who you are you lucky devil, got a bargain. Jeff TT