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Slight Tap Drops Revs

Manuel Kasko
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Manuel Kasko Grand Master

Manuel Kasko

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Hey guys

Just noticed siting at idle if I tap the accelerator slightly it drops revs then picks up.

Idles at about 800-900 but with the tap drops to near 500

Could this be related to my current issue with my throttle being jerky as I either come off throttle or coming onto throttle.

I been reading up and few people said TPS voltage and with the jerking throttle while driving can also be related to the diff needing to be shimmed.

Thoughts guys please?

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https://www.sau.com.au/forums/topic/397867-slight-tap-drops-revs/
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GTSBoy Grand Master

GTSBoy

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It is most likely that the TPS is not adjusted properly. The way I used to adjust it (RB20, not 25, but should be same) before knowing about what the closed throttle TPS voltage was supposed to be was to set it so that the slightest movement of the throttle would cause the injectors to do their little double pulse (you can hear it happen). That was close enough to the correct setting that it was always fine. The actual at rest voltage is about 0.4v.

Manuel Kasko Grand Master

Manuel Kasko

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I will check the TPS voltage when I get a voltage checking gizmo

Tune was only recent and I spoke to DVS about it and he said could possibly be that.

But I only just noticed it doing it at idle so it was kind of hard for him to diagnose over messages

I'll post the results up in here

DVS JEZ Grand Master

DVS JEZ

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Posted

Yes it will be in the tune, wen it goes from idle map to fuel and ignition map. Ur nistune was a bit of a pain in the tps department.

Remember it was way out and i had to adjust the tps trigger voltage. I mustnt have got it perfect.

Try adjusting the tps slightly either way otherwise i will have to fix it up for u :)

DVS JEZ Grand Master

DVS JEZ

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Posted

Yes thats correct. The rb20 ecu has a tuneable tps trigger voltage. Rb25 doesnt as they use a different tps that works off a set voltage to trigger idle maps on and off.

Yes i got it to turn on and off but it mustn't be perfectly adjusted.

U will need a multimeter or consult cable to adjust it. Or u can try trial and error. But make sure u mark it before u adjust it incase u go backwards

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