So as some of you know from a couple of previous threads my black NA Nissan overfuels (Hesitates for a split second when middle to harsh accelleration is used).

 

I know the timing is out thanks to conZult, so ill get the belt done, I also know the cats are shot, so ill get some decats to solve that. My question is about injectors (hence the title :lol:) Would a broken or leaking injector cause my overfueling/hesitating problem? Recently it seems to have got worse but not all the time. Yesterday I drove to work and it was normal (as in normal amount of hesitating and over fueling i.e what its always been like) I drove to the petrol station during lunchtime and reversing out of the space it almost stalled on me, pulling out on to a roundabout I had to dip the clutch and save it from stalling, when off the throttle it popped and banged pretty badly (fuel in the exhaust), but when I drove back to work from the petrol station, its was back to normal.

 

For the past month it seems to be an on/off problem. I can start it one time and have a normal journey to my destination, the next time I start it I have a pig of a journey trying to not let it stall. Some days it does it all day, other days no matter how many times I start it and stop it, it runs fine. While im changing the belt, i was thinking of changing the injectors and cross that of the dianogtic list, but do I need to? If so what in jectors does a 1990 JDM NA LWB take? If I put bigger ones in and get it re-mapped do I get more power or open it up to further problems? This is my daily drive, so prefer reliability (yes, i just used that word! :lol:) over power. Is there anything else I can try?

 

Thanks

I have'nt seen your previous forum posts on this, but hopefully I can offer some advice still.

 

Conzult will only tell you what the ECU thinks the timing is, based on it presuming the Base idle is 15 BTDC. If the timing is out because the Belt is not aligned properly or the CAS has been adjusted then Conzult wont know. If Conzult is showing anything different to 15 BTDC at idle then its probably due to a high idle setting which can be from a faulty or incorrectly setup TPS, throttle valves need adjustment, Idle Control valve adjustment/cleaning/faulty, faulty Water temperature sensor or the Car was not fully warmed up when tested.

 

A lot of your symptoms sound like either a Vacuum leak somewhere or a MAF Issue. Vacuum issues can be hard to detect, luckily the NA has a lot less vacuum pipes to fail than the TT. If you know another local Z32 owners then it may be worth trying their MAF. Faulty O2 sensors will affect fueling, but usually not to the degree you have mentioned. These can easily be checked in Conzult. You should see them sweeping from left to right on the gauge when holding the idle at ~2000rpm.

 

Other than the popping and banging have you noticed a misfire from 1 or more cylinders, in the form of very rough running ? - This could point to Coilpack/wiring/PTU failures.

 

You could still have an Injector failure, but they are less common in the UK, whereas they are a lot more common in the U.S with their higher ethanol fuel. More often than not any injector issues are down to poor connection and wiring which gets very brittle with age in the hot Z32 engine bay.

 

Fitting larger injectors will need a ecu remap and wont offer any performance advantage on their own. Larger injectors are required to provide adequate fueling in conjunction with other extensive engine modifications.

Edited June 15, 20169 yr by Yowser

I have'nt seen your previous forum posts on this, but hopefully I can offer some advice still.

 

Thank you for you advice, its good to hear that you dont think its the injectors, I didnt really want to shell out for new ones. Ill carry on with my plan of changing the belt and then make sure all the things you mention are setup and adjusted properly..

 

cheers! :pint: