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Positive triggering with a DPO?

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I am currently in the process of wiring a Haltech Elite into my 300ZX (Z32). I have been going through the pinout from the 300ZX’s wiring diagram and reassigning pins based on the Elites wiring diagram.

The proiblem that I have run into is regarding outputs that the factory ECU pushed out as a positive signal since the Elite is using a negative output on DPO’s?

For example:

On the factory 300ZX PIN 34 (F1) is a trigger for the Power Steering pressure switch. The way the OEM ECU handled this was to provide a positive electrical output to the Pin 34 and the switch always had a ground present in the factory harness so anytime it got a positive signal it engaged.

I will be triggering this switch with my elite through one of my spare DPO’s. It is my understanding that the DPO’s will only output a negative signal. If that’s the case I and I attempt to trigger this switch with a DPO it will then have 2 negative inputs and do nothing.

I could run the DPO to a relay and flip flop the signal but that seems tedious and unnecessary to have to do on every factory sensor that use to get a positive signal from the ECU.

Haltech makes a platinum plug n play for the 300ZX that plugs right up without the need for additional wiring. How did this unit handle this issue? Was it outputting a positive signal on those channels?

What’s my best solution to do this with the Elite?


Platinum can invert the DPO signal. I have not yet dived in the Elite software, but i would imagine you could do the same there?

Correct. It can invert that signal. What that does is provide a constant ground to that channel and then when triggered that ground is removed. It doesn't make it a 12V out.

Why don't you simply wire it backward ?

Positive directly to the switch and the other end to the Haltech Elite output (just like an injector for exemple)

That should work exaclty the same way

Most aftermarket ECU only have switched ground output to avoid getting the current load from them.

Because it Sounds like he is using the factory loom and just cutting the factory plug off and matching it up with the Elite.

I had to do the same thing on my VS commodore recently with a MSDIYPNP, the factory ecu outputs 12V+ to activate the fuel pump relay... I simply used a micro relay and made it a part of the wiring loom, Stole power from one of the factory 12V outputs of an adjacent wire as well as an earth, since it is only powering the existing factory relay coil there is no worry of overloading the existing circuit... Granted I only had to do this for one output... if you had to do 2 more outputs it would start getting messy/bulky.

Maybe that's just me, but inverting two pin on the accessory side (a pressure switch in Madhatter10-6's case) and reroute one wire seems less work than adding a relay.

As for your fuel pump Reaper Customs, it would have been even easier in your case since you already have a +12v on the relay to supply the fuel pump itself.

(remove the ground to the coil of the relay and add a jumper from the +12v supply)

Saxon, you have missunderstood the purpose of this switch.

It is an powersteering oil pressure switch. It just GIVE a SIGNAL to the ECU when you are activating the steeringwheel (pulling it one way or the other). The ECU then use this message to increase the air (dutycycle) through the Idle valve. This is to stop the idle speed from dropping when applying load to the ps pump..

So wire it to a DIGITAL INPUT, and adjust your "idle up tables" accordingly.

Sidenote. I know that in the Z32 basemap provided by Haltech the idle solenoid is set to work at 300hz. This will make it unresponsive. Set it at 100Hz instead...


Interesting. I din't know that. I assumed that it was similar to how it works on the 2J where it actually needs to be activated. Thanks for clarifying that.

Unfortunately that was just one of the items that had that problem. Another example would be the VTC system. It constantly has a ground and needs a power signal to engage it. So I am right back in the same boat of needing to trigger an item with a positive output. I really don't want to chop the harness up or use micro relays but it may be inevitable.



VTC is just grounded through the ECU.

There isnt any doohickeys on the car that need + through the ecu


I just looked through all of the wiring and turns out your correct. The OEM harness has constant 12V. Thanks so much for your help!

No problem mate.

Glad i could stop you before you hacked up the loom.

BTW, did you end up getting an extention harness or did you eventually find a ecu plug to use?


I knew your named looked familiar...just recognized it from tt.net!

Yeah. I found a patch harness that I am going to modify to work with the Haltech

Sounds good. Have fun with it.

Now if you recigniced my name you may have picked up on me beeing a big advocate for ditching the stock CAS and go for a real cranktrigger. This is a clever move when you have an upgraded engine and ESPECIALY when you have an aftermarket ECU. The stock ecu use an algorythm when reading the CAS that none (that i know of) of the aftermarket ecu`s replicate. Unstable timing WILL be evident wether you like it or not. Just food for thought :)

On your setup didn't you use an ATI dampener with custom teeth?

Did you still use the CAS but only for cam position?

Correct on both.

Got a custom ATI damper and a AEM disk in the cas for a single synk signal.

Interesting! I may end up going this route. What sensor did you use to read the crank? Just make a custom mounting bracket?

Also, why couldn't you have used the factory CAS disc for cam position instead of AEM?

As my damper was a "special order" it took its time. I believe i waited for it about 6 months iirc. The pricetag isnt for everyone either. Around 1100usd. So if any of those factors is a hard one to swollow one can always try to mock up something else that works.

I have 24-1 triggerpattern on it and i use the Honneywell "gt101" sensor. Works without a hickup. Supposedly those sensors dont like too high toothcounts at high rpm so i woudnt go above 36.

The factory cas got 6 different lenght slots in it to tell what cylinder it is working on. The AEM got only one.

I cant imagine your ECU will support a combo of say 24 on the crank and the stock nissan pattern on the cam. If it DOES (you will be able to check in the software) then go ahead, but i doubt it.

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