Diagnostic plug not working.

I've got an issue with my car constantly going into limp mode as if the Knock sensor has detected DET. The boost gets limited to 0.5 bar and you can feel the timing getting retarded and engine running sluggish.

I've had my car in my local garage and he says he cannot get his diagnostic computer to read it. I'm not sure what he is using but he swears it should read it no problem and I know one of the main mechanics has cars like skylines, scoobys and GTO's etc.

He asked me if I could get the diagram for what pin is what on the diagnostic plug if anyone can help me?

All these strange little electrical issues are worrying me though because it's proving to be a real pain in the arse to get sorted.

http://www.gtir-motorsport-club.com/t81-ecu-fault-code-check

Yeah I dont think you would get any more from an obd1 reader than that nissan consult cable can give some readings but more monitoring. Best bet is to start fault finding and see if it is a DET code showing up

You need to check make sure you have the wires there in the right places ... do you have a electric tester bill ???

Yes I have a multimeter, that knock sensor is a damn nightmare to get to though lol.

I've noticed on my hks turbo timer that the voltage only reading around 13.1-13.2 volts the majority of the time when driving etc. Does this sound abit low to you? Could low alternator voltage maybe cause all my running issues? I have a slight misfire at part throttle at around 2krpm that I have never been able to diagnose. I noticed today when revving the car in neutral the battery light illuminated slightly at high rpm.

Just trying to throw some suggestions out there because I haven't got a clue what causing it

I'm going to go do a fault code check now and see what I get

It is showing code 34 DET sensor

I'll take it for a run now I've cleared the code, see if it come back

If the battery light is coming up even if its dim i would be defo checking it ... put a multi meter on the battery see what volts you get should be 12.4 .... then start it up and do the same again you should be getting around 14.0 volts roughly ... give it a rev with multi meter still on the battery see what you get ... whatever your findings post up what you get ... also worth checking battery terminals to make sure they are all good aswell ....

It went straight back into limp mode. I'm going to give it a rest now until tomorrow because I don't want to go waking everybody up lol. Will post up what voltage readings I get tomorrow but I'm sure the voltage displayed on the turbo timer is accurate, if so then the voltage is about 13.2 volts when at cruising RPM

Thats quite low it should be more than that to give a sufficiant charge to the battery ... was the new det sensor a oem one or second hand or state of the wire ... sure it wasnt caught doing the gearbox change ???

It's a new sensor and genuine Nissan, although i got it cheap from the US and had it a while before fitting.

I asked the garage to take a look at the DET sensor while it was on the ramps but I'm not sure if they did or not because I had a lot of work done so they could of easily forgot. I forgot to ask when collecting the car.

As said tomorrow I will give it a proper good look over to the best of my efforts, I've compiled a little list for myself or the garage if I go back to get them to work on it lol
if anyone can think of anything else to check then please let me know, any help and suggestions are welcome lol.





Car going in limp mode. Showing code for DET sensor.
Check torque settings on DET sensor as must not be over/under tightened.
Check plug and wires to DET sensor (spray with contact cleaner if needed)

Possible low voltage from alternator/battery?
Wire going into plug on alternator in poor shape, battery not the best.

Oil leak from distributor (possible ignition system problems from this)

Other faults worth noting:
Temperature gauge is erratic when on boost (temp sensor, possible bad earth)
Aftermarket rad-fan control fitted due to fans not kicking in (possibly related to above issues)
Has slight misfire at partial throttle at around 2krpm (possibly related to said issues)
Battery dose not hold charge for longer than a few days

Other things to check:
Look for any sign of any metallic object that could be vibrating against the block causing the sensor to pick up false knock.
Check ignition timing (may be unable to adjust correctly if in limp mode).
Check voltage at fuel pump (known issue with voltage drop on old wiring).
Check tps


There are a few things on that list I won't be able to do myself but I want to at least narrow it down a little befor I hand it over to the garage and spend another small fortune

On the way down to the last rolling road at Bobs mine developed a noisy rattle, battery light coming on, trying to cut out at junctions.

Bob and Johnny checked it over and although it sounded like a big end knock it was the alternator bearings shot, Johnny changed it with a good one from Bob and all was sorted.

Hopefully that's the same issue you've got mate.

Yes it would be nice to find out it was my alternator all along, I've spent a small fortune changing parts hear and there trying to fix little issues.
It's a brilliant day for it today, I better get my waiders on lol it's slinging it down!