Ive been looking at buying some pre 94 nismo 555's injectors for my zed as a few of you on here have advised me to do. But ive found some worrying info on another zed site in canada after looking for info on the injectors on google.Has anyone had this trouble???
Well, now I know why I keep eating so many fuel injectors. Apparently it's normal for Nismo 555 injectors to last only a year in the 1990 to 1994 300zx...
http://www.twinturbo.net/net/viewmsg...msg_id=1535571
Some more comments from Greg @ SpecialtyZ:
We have had many,many,many nismo 555 injectors fail in the last couple
years and nismo will not do anything. some of the early style injectors are only lasting a couple months. Since the fuel changed with alcohol content they are all failing extremely soon.
I feel for you that your experiencing problems with nismo injectors and
you are far from alone.
What is happening to the injectors is that they are corroding the
internal connection and causing an open circuit. The injectors are not getting shorted coils from running past their duty cycle.
The early style injectors have positive 12 volts all the time. The fuel
formula changed a few years ago and they started adding alcohol to the
fuel. Since the time the fuel was changed the injector failures of cars with
early style injectors is through the roof, (brand new and original early style
injectors we are replacing several a week). It is believed the alcohol
and having power to the injectors is causing electrolysis and eating up the
connections internally causing the high failure rate. They are not
having this problem in Japan and they make fuel the way we use to without
alcohol. The injectors were originally designed for fuel that we do not have any
more.
The stock injectors use to last 10 years easy and we hardly ever had
failures......Now we are having to replace stock injectors that have
already been changed in less then a year all the time as well as original
injectors failing almost daily. The late style injectors are wired to the ECU differently and do not have power when the key is off.
By old style, I mean the 1990-1994 year style injectors.
The new style injectors that were used in 1995 and newer Z cars are
completely different in design and require different code in the ECU and do
not have power going to them from the ECU until the key is turned on.
They also require a different fuel rail to bolt them in.
They are not directly interchangeable. It requires different fuel rails and
machining of the lower intake manifold to accept the newer style fuel rail.
It also requires changing the injector electrical plugs and ECU chip.
You absolutely have older style injectors because that is all you can use
without major modification and changing all the injectors to the late model
year style.
Your only option at this point is to replace the one bad injector unless
your willing to go to the expense of replacing all of them and doing the
modifications to change over to the complete new set up.
Nismo is aware of the problem now and we have a lot of documentation.
We are hoping nismo comes up with a solution for direct replacements.
I am recommending to people doing upgrades currently to change over to the
new style now they we know there is a problem with the old style injectors
combined with our current pump fuels.
For years the Nismo 555cc injectors were a great relieable injector.
Other company's selling injectors for the early application are assembled
the same way and the ECU program for the early style injectors has the ECU
sending power to the injector all the time adding to the electrolysis
problem.
Mike Smith and JWT are looking into ways to help the injectors live longer
by wiring the injectors differently. This is still in the testing stages and
we are hoping to offer at least a patch of some kind to help with people
that have these injectors.
I feel your frustration, I had to change 3 of the 6 injectors in less then a
year on my personal 300ZX that had the HKS 2530 turbos......I replaced them
all with the newer style 740's and fuel rails when I put JWT 700 turbos in
this last year.
I still have all my 555cc Injectors in my 280z that has the twin turbo
motor and Greddy TD05 turbos. I did wire this car myself when I did the
engine conversion and I do not have power to my injectors when the car is
off.
This just happened by accident because I wired the car and the fuel
injection relay does not have power until the key is turned on.
Greg
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Canada's Nissan & Infiniti Tuning Specialists!
