Tuning Question - Post Injector Resistor Removal

[jonathon]

Hi all,

I've recently had some work done to my r32 gtr, (larger injectors, boost increase, adjusted cams) and have had a retune (nistune).

I've driven the car and competed in a hill climb, and all is well, however all of a sudden was unable to start the car.

After investigating- turns out the injectors are high impedance not low (was advertised as direct replacement - I guess that doesn't mean anything!). I've now removed the resistor and it's now running again.

So my long winded question is - would it need to be retuned now the injectors are getting correct ohms/power?

Or doesn't it make a difference? Was strange how it was running well for a week....

[Ben C34]

That is an odd one.

I would certainly check afr on a dyno (I assume you don't have a wideband installed)

[MJTru]

This is weird. I wired a power fc for a gtr to work in a gtst. I got it and it all worked good. Of course I had no vtc. What I learned was that all rb ecu wants to see a high impedance resistance. The rb25 are high impudence injectors and the gtr rb26 are low but the gtr has a resistor pack to boost the low impedance injectors to a high ohm reading. So in short all ecu's wants to see high impedance signal. I really think nissan thought peopel wouldn't get this. Lol. If you have high impedance injectors on a rb26 ecu.?? Just get rid of the resistor pack (rewire) it and you will be ok. From a resistance stand point.

Edited June 28, 2014 by MJTru

[GTSBoy]

Um....Marcus....that's exactly what he said and did.

OP.......Yes, retune. The opening behaviour of the injectors will be different without the resistor - effectively the latency will probably be changed the most - so it will affect light load mixtures more than high load, but still worrth doing.

[jonathon]

Awesome - thanks for the help guys.

Such a pain in the backside - as it only just came back from the tuner!

So are the injectors slower to open? I'd hate to be driving it running too lean...

[MJTru]

Um....Marcus....that's exactly what he said and did.

OP.......Yes, retune. The opening behaviour of the injectors will be different without the resistor - effectively the latency will probably be changed the most - so it will affect light load mixtures more than high load, but still worrth doing.

Yes GTSBoy I agree thats what he was saying. I may have missed somthing tho. A rule of thumb for me is. Any mods to fuel or air should be mapped and retuned. Intresting info GTSBoy as I never thought it would affect the injectors the way you mentioned it. I will be looking into this. Also intresting to know it would make more difference in the down low area. Hmmmm

[MJTru]

Damn ant know how I missed all that. Its the same damn thing he was saying-_-

Edited June 29, 2014 by MJTru