Hi can someone help me ,my na 2 seater 300zx auto has just had a plenum pull and other mods that are done when u do a plenum pull.My car was done at the Z shed by Brian at a very reasonable rate and runs alot better than before.Only problem i have is very high fuel consumption a full tank in 300km at normal to slow driving ,my car also smells of fuel at times ,brian told me the fuel pump is running at 12volt all the time at should be at 6 volt when the car is running??Also my cat light stays on alot ,can someone help me?Can anyone help me get in contact with bryan trying to call him for months
Hey mate, brian is still recovering as far as I know, I can't get in touch with him atm either. Give him time to get better and I'm sure he will get back to you
your cat light will be caused by all the unburnt fuel going down the exhaust as i had the same problem with mine.you may even see your cats glowing or feel the heat of your cats through the floor near the console. did bryan replace your connectors or just clean them , are all cylinders firing,does the engine bay smell like petrol?
the fuel pump it running 12v probably because the fpcu has been bypassed. That's not going to cause you issues though. Does it smell like unburnet fuel or raw fuel.
The fuel smell in cab is usually associated with a leak/vapour leak between the tank and the filler cap. There is a reducer in the filler tube, that allows the cap to thread into it and lock up tight. This reducer tends to break the seal between it and the tube. There is a tech article floating about that explains how to fix this, but if in doubt, search it. Its been covered several times. Excess fuel consumption, welcome to the land of zedding. I doubt there is anyone on the forum that hasnt had a minor or large fuel consumption issue. There are a series of options as to explaining the reason for this. So also recommend searching the topic. Furthermore, as mentioned by the above members, the cat lights on due to excess unburnt fuel entering the exhaust system. So clearly you have either an injector issue: injector(s) stuck open, or a senser issue: oxygen sensor, afm, etc. As for the fuel pump at constant 12V, nothing serious. As mentioned the fpcu has obviously failed in your zed, requiring the need for a bypass. But dont be concerned about it. Have a good search regarding your issues, all will become clear. Good way to learn and try some diy'ing.
Also take a look at your fuel reg, swap it out for a known good one. It could be not letting fuel return to the fuel tank.
I'd be having a very careful look and smell around your engine bay for fuel, there are a reasonable number of fuel hoses as well as things like the regulator that need to be tinkered with for a plenum pull.
ok how do i know if fuel injectors are not operating properly?can they come out easily ?How do i check them?would brian from z shed overlooked such a problem?
I had the same isssue on my old twin turbo which turned out to be a split fuel line running to one of the injectors - raw fuel all over the engine.
Not having read all the replies I thought I might just add, I had similar problems and after much analysing realised it was simply because I filled her with 91 octane fuel. Was a stupid thing to do but also a very easy fix. topped her with 98 and alls good. Other possibilities I ran through whilst having similar issues was O2 sensors, if you've driven through water or just flooded the engine with unburned fuel, I've been told that can stuff them, and they need cleaning. Also check for ignition of all spark plugs, they may need cleaning.... I had problems of running rich and hot. A later discovered broken rad fluid temp sensor also didn't help.
thanks for your help ,what should a good running na auto get to a full tank of fuel under normal driving?
It all depends * city driving ? Rush hour ? Not very many K's * freeway driving at 100k/h and flat country - lots of K's * hilly country roads - in between BUT, how do you define a a full tank ? 40l ? 50l 60l ? Keep records and do your stats - only way. K's on a tank means nothing ! Different to everybody Here's the convertible (NA) consumption
There is NO normal city driving. Rush hour, main roads, back streets, day time night time ..... You saw my chart. Do your maths, define what sort of traffic you drive in and tell us what consumption you get over a couple of refills. How many l/100k have you had lately ?
i think i was clear in what i originally said a full tank of fuel slow city driving never more than 300km from 60litres of fuel ,so that 20liters per 100km slow driving most under 80km that surely must be alot of fuel from a 3litre non turbo motor car dont you think???
