Adjusting the idle

[Race Grandpa]

I had a new engine installed about 700 miles ago and when I picked up the car the shop said that the idle would be adjusted after the break in period. (When SC would have the belt working.)

I have reached the 700 mile mark and it is still idling at 1,500 rpm.

Since I am going to delay putting the SC on line, I am not sure if the idle should or can be adjusted w/o the SC functioning.

If the idle can/should be adjusted as the engine/SC are currently, where do I find the adjustment screw?

[Tom @ Fast Forward]

The blower does not need to be running to set the idle. It is set by the idle stop screw on the side (passenger side) of the throttle body.

[Race Grandpa]

Well I found out that I was not crazy and not out in left field.

I still could not find the adjustment screw on the throttle body. So I took it to the dealer have them look at it.

The tech told me that the throttle body is not an OEM throttle body, but an after market throttle body. The adjustment screw is on the bottom of the throttle body.

I have no idea why I have an aftermarket throttle body. The reason might be that the shop that did the SC installation mixed up one of their throttle bodys for their Spec Miata 1.6 engines with mine. Given the problems I had with the shop they will not talk to me.

The tech thinks that the idle was set at 1,500 rpm because when the SC is functioning it adds an additional load that will bring the rpms down into the normal range. ??????????

[Tom @ Fast Forward]

The after market throttle body is a BBK 75mm one. It came with the kit to replace the stock throttle body. It helps make more HP. The adjusting screw is towards the bottom on the passenger side of it. The idle should not be 1500 RPM. Your car should idle just fine at the stock ~900 RPM setting.

[Race Grandpa]

Thanks Tom. I did look at the list of parts that came with the kit. However, I did not see it.

Getting to old and the eye sight is failing. :1eye:

Actually, the coke bottle lenses I have can not a make full correction. Now I wonder if my ears will be good enough to hear any potential pinging!!! Will take care of that with lower A/F ratio.

Thanks again.

[BlownMX5]

The tech thinks that the idle was set at 1,500 rpm because when the SC is functioning it adds an additional load that will bring the rpms down into the normal range. ??????????

The supercharger has a bypass valve on it that allows it to spin freely at idle. It adds almost no load to the engine at idle.

[Race Grandpa]

The supercharger has a bypass valve on it that allows it to spin freely at idle. It adds almost no load to the engine at idle.

"I see" says the blind man.

:no: