i have a 1990 Z N/A.
just to give you a lil history on the car. I bought the car in jan a month later the engine started missfireing. took it to a shop and they told me it was the fuel injectors so i had the fuel injectors replace... wich ended up coasting me $1,200.oo (wayyyyy to much i know. they ****ed me good) then they told me it wasn't the fuel injectors after all that its the motor harness, theres a short in the wire to the #1 cylinder... i brought it to another show and they confirmed this.

now i'm quoted at another grand for this work.. cheapest i found.

everyone i talk to tells me i need to remove the motor to do this replacement.. is that only to get the ecu connector through the fire wall? or are there actually connectors on the rear of the motor i cant get too?

i found this page that indicates the locations of the connectors but dosent explain how to replace it.
http://www.300zx.co.uk/cgi-bin/manual.cgi pic is on "page. 132", under the "Electrical System" chapter

dose anyone have a write up with pics?
do i have to remove the motor?????

 

It's not connectors that you can't reach that are the problem, it's actually reaching the opening on the firewall and having enough clearance to get the ECU connector through. You don't need to remove the engine, though... if you're mechanically talented, I'd recommend removing the intake plenum (there are several writeups for that on tt.net)... that'll give enough room to do it.

But before doing that, buy some new injector connectors and just splice those into the harness you have. It's never a bad idea to replace the harness, but it's not common for the wires to break anywhere but at the connector so I'd bet that splicing in a new connector might solve your problem. And if it doesn't, it didn't cost much to try.

 

Thanks man.

Is it possible to get the connector through the firewall without removing the plenum? i've removed the plenum before to replace my fuel injectors and it wasn't fun, i was outside in a parking lot in 35 degree weather.

 

you are just splicing in new connectors. it takes a couple inches of wire.

 

Did you ignore the part about splicing on new connectors?

If you've removed the plenum before, you should've eliminated the EGR system and did the coolant bypass... would've made future plenum pulls 10-15 minute jobs. My advice is to suck it up and do the plenum pull and eliminate that crap this time so it's easier in the future, because you absolutely won't be able to get the connector through the firewall with the plenum in.

Your only options are as follows:
splice in new connectors and hope that solves it
pull the plenum and replace harness
pull the engine and replace the harness

 

no i'm def not gonna splice on new connectors.. i'm sure its a good option.. but i'd rather have a hole new harness.

plus as far as removeing the egr and all that.. i had no time to do this durring the original pull. + i dont know the steps or all of the parts i need to remove.. if you could lead me in the right direction.. i'd like to know all of the unessasery components i can remove.
i mean i am mechanically inclined.. i just know nothing about cars.. i can do the baics... exhaust intake oil/ brake change.. but i dont know all the mechanical aspects of all the parts and what they do..

 

EGR
http://www.twinturbo.net/net/viewmsg...&msg_id=967920

Coolant Bypass
http://www.twinturbo.net/nissan/300z...ease-VTF).html

 

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OHH HELL MOTHER ****EN YES!!!!!!!!!!!!!!!!!!
I just completed my first EFI swapp EVER! without even removing the motor or the plenum. And it took me 5 hours. dont know if thats quick or not.. but its done.

Emediatly after i noticed that the car nolonger missfired, all of my interior and exterior lights are brighter, quicker throtle responce.. **** its like i got a brand new Z... HAHAHA. Now i just need to tackle my exhaust.

I'd like to thank all of you who have helped me find the information i needed to finish the swapp.

one step closer.

Z Fiend

 

To put it into perspective, I can pull my engine in less than four and a half. Would've been faster with the plenum pull, but I'm glad to hear you got it done.

 

ok i'm lost.... after i finished my efi swapp the Z ran awsome.. turnoed it off, went to bed.. woke up saturday, drove all day no issues. Z drove awsome.. i put about 200 miles on it that day... sunday rolls around, ceck engine lights back on and its driving crapy again.. any ideas?

 

Yep... PULL THE CHECK ENGINE CODES.

 

Do me a favor and test your new injectors too... it wouldn't be the first time a new injector failed.