i have a miss fire which i have narrowed down to cylinder 6 i changed coil the other day to cylinder 1 but fault stayed at cylinder 6 so im guessing something on cylinder 6 now the no 6 coil pack plug is pretty crap to be honest. but is just a case of changing the connecter and problem solved or will it be something else i need to look for?

If you have'nt confirmed if its definatly spark or Fuel related yet, do as Mikey described first.

 

Actual Injector and Coilpack failure is rare, its usually the Wiring loom and connectors.

 

It may even be signs of the PTU on its way out. A common failure item quite typical for it to fail on one circuit before eventual failure across all.

 

The wiring looms are notorious for failure at this age. You will probably find most of it is brittle.

 

Injector and coilpack connectors tend to build up corrosion on the metal contacts. Check and clean them up, and try wiggling the injector and coilpack connectors and wiring gently to see if it fires into life.

 

A complete new loom is around 300 pounds, but is probably one of the best reliablity investments you can make for the Z. Alternatively you can get new coilpack and Injector harness looms for less which you can cut and solder into the old main Loom.

Edited April 22, 201114 yr by Yowser

only thing i have done is un plug the the coils and only plug 6 didnt effect the miss fire which is why im guessing something wrong with cylinder 6 which of cause is the most awarked one to get to plus i dont have a spare coil to try! also i dont always have a mis fire as it comes and gos as it feels so im hopping that points towards electrical and not rings or head gasket? it has also had a serious 2 ptu fitted or so i was told by previous owner

oh right i see what you mean! ill give it a go monday as im hopping my brothers gf has picked some bits up from big jim for me to fit!

Wiring/connector issues with the Injectors are just as likely as Wiring/connector issues with the Coilpacks.

 

The Injector connector sits a couple of inches in from the coilpack. They use a smaller plastic connector with a metal pin to hold them on, although they are often broken, or break when removing.

 

you dont need a spare coil matey just a spare spark plug. remove the 1 coil and insert 1 plug. lay it so the plug is touching somthing metal on the car or engine and start it up. if you get a spark then the wiring is probably ok:)

 

* If you get a spark then the Coilpack wiring is ok, and its most likely a wiring or connector issue with the Injector instead.

Edited April 22, 201114 yr by Yowser

Intermittely , I'm of the mind the injector is starting to fail. Ohm it out and see what you have. My Z has pulled the same thing twice now and both time it was the injector. Would not hurt at all to clean all the connections and put some dielectric grease on them to keep the moisture out.

Intermittely , I'm of the mind the injector is starting to fail. Ohm it out and see what you have. My Z has pulled the same thing twice now and both time it was the injector. Would not hurt at all to clean all the connections and put some dielectric grease on them to keep the moisture out.

 

Certainly could be, but for you guys in the States injector failure is far more common becuase of the increased Ethanol content in your fuel.

Certainly could be, but for you guys in the States injector failure is far more common becuase of the increased Ethanol content in your fuel.

 

True. Good point. I have only one station in my area that is ethanol free and he evidently is proud to offer the 93 octane without it....$4.08 a gallon , I know , I know. Simon has already scolded me on what you guys have to pay. Still here its over $1.40 a gallon more than last summer.

well i see on flea bay that they do a set of 6 injector connectors for £36 plus postage from usa! anybody bought these? if so how much was the postage?

 

http://cgi.ebay.co.uk:80/ws/eBayISAPI.dll?ViewItem&item=360356979484&category=46098&_trksid=p5197.c0.m619&autoredirect=off

 

 

im thinking for £40 i should change them along with my recently bought coil plugs that way i know my wiring is good. is there an easy way to test the ibjector? im not very good with ohm meters! lol

well i see on flea bay that they do a set of 6 injector connectors for £36 plus postage from usa! anybody bought these? if so how much was the postage?

 

http://cgi.ebay.co.uk:80/ws/eBayISAPI.dll?ViewItem&item=360356979484&category=46098&_trksid=p5197.c0.m619&autoredirect=off

 

 

im thinking for £40 i should change them along with my recently bought coil plugs that way i know my wiring is good. is there an easy way to test the ibjector? im not very good with ohm meters! lol

They would do the tricl but looks You dont get much wire with them, I'd want some a little longer as quite often there can be breaks in the loom within the 8" area beforethe connector, as thats where it twists and turns the most between the plenum and balance bar..etc

 

MJP supply them, a little more expensive but they should be the OEM sub harness with longer looms than them http://www.300zx.co.uk/forums/showthread.php?t=149295

 

Check the condition of the connectors and give the loom a wiggle, if its an intermittent fault with the loom or connectors that will quickly tell you, before purchasing any.

Try giving the wiring a wiggle and seeing if it makes any difference. I have an intermittent misfire on mine that is down to a missing clip on the PTU connector and when the engine/wiring loom moves it pulls the PTU connector slightly to an angle (it moves probably 1mm or less) which must move it out of proper contact with the PTU - it shows how easy it is to cause a misfire with anything dodgey on the wiring side of things.