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

__________________

Canada's Nissan & Infiniti Tuning Specialists!

I have the old style Nismo 555's for over 5 years now.no problems at all.

 

it's this particular line that says it all (imo) : Since the fuel changed with alcohol content they are all failing extremely soon.

 

He is reffering to the ethanol bio fuel widely used in the US.

Most early style (14+ year old) injectors, like the stock injectors, were not designed to run on this kind of fuel, hence the failures

They are Talking about the crap fuel in the states. They are also saying that the standard 370cc injectors of the pre November 94 cars are also failing. Which is hardly suprising as both the Original Nissan 370's and the Nismo 555's are Sard injectors of the same design. In the UK we don't have this problem and many 1990 TT's and NA are still running around on their original injectors. So don't worry.

Had my Nissmo 555's fitted for years and never had any probs at all.

great was hoping this was the case!

thanx for your help

if you were really paranoid and worried there is a ecu loom mod to sort it out anyway, look on aus tech index for it