04 Disco 4.6 idle adjustment?

[4Runner]

Can you raise the idle with a diagnostic tool? Looking to go from 650rpms at an idle to 750 due to a cam that is lumpier than expected. No stalling issues or rich adjustments to the short term fuel trim, it just is a lot smoother at 750. I don’t know of any mechanical adjustments on a Bosch motor for the idle. Thanks for help.

 

[rovercanus]

You can adjust your throttle cable. Not sure what effects this will have down the road.

 

[4Runner]

I thought about that but figured the ECU would close the IAC more to compensate for the extra flow from the throttle plate. I would have to open the plate enough that the IAC was completely closed and then adjust the TPS back to a closed signal. That doesn’t seem like the right way to do it at the moment. Was hoping you could just change a setting to idle at a different target rpm.

 

[Swedjen2]

I have the same issue. You "could" drill a small hole in the throttle plate. Start very small and work up.
I haven't done it, so your it.
I don't know what secondary effects would occur.

 

[rovercanus]

I thought about that but figured the ECU would close the IAC more to compensate for the extra flow from the throttle plate. I would have to open the plate enough that the IAC was completely closed and then adjust the TPS back to a closed signal. That doesn’t seem like the right way to do it at the moment. Was hoping you could just change a setting to idle at a different target rpm.

It's easy enough to do and undo. You could reset your adaptive values and pretty much know right away if the ecu will try to accommodate for the throttle position.

 

[4Runner]

At the moment, I don’t have a diagnostic tool to reset the adaptive values, so I would have to take it somewhere or buy one. I have almost purchased one a few different time now. Maybe this will push me over the edge. Your are right, it’s easy to try and undo. I also thought about the throttle plate hole. I haven’t seen that since the Holley carb days. That one is more difficult to undo but is still only a 30 dollar trip to the junk yard if I want to change it back.

 

[Discomania]

Of course, if you decide to drill the throttle plate, drill the one on your junkyard find. That way, if it f*cks something up, you can just bolt your old one back on and relish the new knowledge.