Honda Civic Turbo high idle and running rich

[H0ndaTurbo]

Hi guys,
I've been having this problem and am running out of ideas. I rebuilt my 1996 honda lx engine and put an ebay turbo on it. It runs and drives fine, except it idles close to 2000 and it runs rich. I have tried adjusting the fuel maps and tuning, but am unable to lean it out. It's usually around 10-11afr. The idle is constant and doesn't idle hunt. I bought and installed a new iacv to no avail. The only vacuum leaks I can find are slight leaks on the turbo housing and, weirdly, from the turbo oil return line where it connects to the oil pan.

Any ideas would be greatly appreciated. I have been trying to get it to idle correctly for almost a year now and am trying this thread as a last resort.

 

[XpL0d3r]

What are you tuned on and what ECU? How much boost and what map sensor? Injectors?

High idle could be something like your throttle plate stuck open.

However, I would recommend taking it to a tuner.

 

[H0ndaTurbo]

What are you tuned on and what ECU? How much boost and what map sensor? Injectors?

High idle could be something like your throttle plate stuck open.

However, I would recommend taking it to a tuner.

I have a chipped p28 ecu and am using Neptune RTP. I have a omnipower 3 bar I believe with 850 cc injectors. I dont think it's anything so simple as the throttle stuck open...

I would like to take to a tuner as a last resort, but if it's a mechanical problem they'll likely send me back home :/

Thanks.

 

[XpL0d3r]

I have a chipped p28 ecu and am using Neptune RTP. I have a omnipower 3 bar I believe with 850 cc injectors. I dont think it's anything so simple as the throttle stuck open...

I would like to take to a tuner as a last resort, but if it's a mechanical problem they'll likely send me back home :/

Thanks.

It depends on where you go, I suppose. When I was getting mine tuned, we ran into some issues. The small stuff they were able to do (replaced peak/hold injectors with saturated ones so they removed the resistor box), etc... but stuff like replacing an entire engine harness I went ahead and did.

It probably isn't something as simple as a throttle stuck open, but it doesn't hurt to check the basics. Fix your vacuum leaks too -- any extra air in the system can confuse it, especially if you're running an open loop tune.

 

[Szady]

Is this at idle no matter if the engines just starting/cold, fully warmed up, etc? Usually a high idle is some sort of air leak coming into the throttle body... What engine do you have? The D16y7 I assume because you said LX? Try replacing the TB gasket with a new OEM gasket, and make sure the throttle plate stop-screw is adjusted properly (along the lines of what @XpL0d3r suggested). If the screw is out too far, the throttle plate won't close...

Is the tune set to closed loop even at idle? Im not sure how Neptune runs, but in some tuning software you can run open loop at idle so the ECU looks up factory fuel maps until the engine warms up, with no load on it. If you're in open loop at idle, no matter what adjustments you make to the fuel maps, the ECU will over-ride it because it's looking at the 'preset' factory maps to adjust fuel...