Fitting the new EFI harness

This is a dog of a job… I read a few places that a few people have done this with the engine in. Personally i would say this is impossible. They are either telling porkies or know something we dont, its a very difficult job to do and you will need to be very patient not to damage anything.  Keep your cool and take your time then it will be ok.

  1. The first thing to do is to remove the old harness, thats quite simple after five minutes of trying to pull it through the bulkhead give up and cut it out!. Please remember to remove the ECU end and the plug slightly higher up behind the dashboard.
  2. When it is out keep all the bits and make sure that your new harness is the same as the one that came out. If all the wires are the same you might want to spend some time and labal all the main connectors to make things a bit easier later?
  3. Remove all the foam padding on the inside of the bulkhead hole, simply pull it off. Now you will see the reason that you could not pull the the old harness out. There is a metal plate that bolts over the harness from behind the dashboard. At this point you have two options. Take the whole dashboard out to remove the two 10mm nuts holding it on or (as we did) use a hammer and chissel and hit it until it starts to break up.  Take your time and slowly destroy it until you can grab parts with pliers bend them and pull the bits out the hole for the harness.
  4. After you have all the main parts of the retaining bracket out stick your finger in there or an endoscope and have a look for sharp edges. We spent about another hour and managed to break a spanner in half and actually unbolt all the remains when we had most of the bracket out from the engine bay.
  5. You can get the big connector all the way down but you will need to de pin the two small fat connectors as they will not fit. make sure you keep notes and pictures of what pins go where. Then protect it all in black tape or something similar so you dont damage it behind the dashboard on anything. We also taped a long piece of strong wire to the end.
  6. Feed the long piece of wire you just taped to the end through the dash towards the ECU. Then feed in the main loom. It will all then pull through, remember to take care not to snag it up or force it as you could damage the wires. To get the big connector behind the bulk head there is a good chance that you will need to pull the bulkhead on your car about a bit. Dont worry to much about that as a rubber grommet goes in there from the harness after.

Happy days!!!



Note the blood stains on the bulkhead! no pain no gain….


3 Comment(s)

    jimmer | Apr 5, 2010 | Reply

  1. Hi Martin,
    Done three with the engine in,no porkies honest.The engine side is the easy bit.THE DASH SIDE I HATE !!

  2. Trond | Jul 16, 2010 | Reply

  3. This saved me sooooooo much time!! love your site man!! :)

  4. shain | Nov 17, 2010 | Reply

  5. i have been getting a on the engain of my 300zx and i was wondering if i change the connecting rod bearing and put acl race bearing would that fix the problem

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