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Idle Problems - Higher than set and lean - Haltech Elite 2000 1uzfe

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Hi Team,

I am struggling to get my 1uzfe to idle correctly on a Haltech Elite 2000. I am only trying to sort idle at the moment so I can make sure everything is functioning correctly before going to the dyno.

I have the rpm set at 900 across all temp cells and target lambda at 1.0. No matter what I seem to change, the engine runs at around 1500rpm and 1.2 lambda. I've tried/checked all sorts of things. Closed loop, open loop, zeroing offsets and gain, adjusting base map, turning off idle control, blocking off idle control valve incase it was stuck open (this obviously ruins the rpm altogether but still runs lean), reversing its polarity, checked for vacuum leaks after the throttle body, checked TB plate isn't hanging open. I've checked wiring and sensor calibrations. I've thrashed google and youtube. I've completed the Tuning Fundamentals, Practical Tuning, Understanding AFR courses and watched the Idle Control webinar for the Haltech Elite on here. I'm at loss here.

Not sure if its idling high because it running lean or visa versa. Or if there's 2 separate issues there.

Engine is unopened, non vvti, running COPs, 750cc injectors, 2 wire BAC valve, factory throttle body and intake, it is turbo'd but isn't seeing boost yet, Turbosmart FPR set to 43.5psi.


Thanks in advance,


Been a while since I've looked through the software but in the idle settings there's a tab for minimum iac valve duty cycle, at least there was in esp and I'm assuming it's the same in nsp.

If this table has a setting of 50% for example you might be trying to reduce idle speed in the main base duty cycle table (correct) but any value below 50% will have no effect, due to the 50% min duty set up in that separate table. I'd start by checking there, it's also helpful to bring up gauges with relevant info like the actual iacv duty cycle and see how it's tracking against your main idle base duty cycle table as you attempt to tune it.

The symptoms scream "vacuum leak" - what process did you use when you checked before?

I know haltech used to have a single line idle fuel vs rpm array that some people activated which mean the main fuel table wasn't active with throttle shut, I'd double check it isn't something like that combined with a vacuum leak.

I agree sounds like a vacuum leak. If this is a cable throttle, can you close the throttle more?

Too much timing can also cause the RPM to be higher than expected. Is the ignition timing correct, and verified with a timing light? Any chance the TDC mark isn't correct on the engine?

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