throttle plate screw question with pic

[Slammed0]

My check engine light came on a few weeks ago. Well while my dad and I were doing some diagnostics on it to figure it out, he was under the hood and he was messing with this idle screw, as seen in the picture. I didn't know he had planned to mess with it.

So my question is, did he mess with the engine management at all? The car seems to be running properly. I figured whatever he did there the computer would compensate for it. I just wanted to double check with somebody who might know. Thanks! 96 2.0 GS 5 Speed

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[blcknspo0ln]

I'm not familiar with 420a's at all, but are you sure that is a BISS ? If it is, backing it in or out will cause the TB to let in more/less air, therefore decreasing/increasing engine RPM. On a 4G63, if it slightly off, the ECU will always want to idle at 750 so it will try it's hardest to get back to that base idling RPM.

 

[WMD]

I see you have a CAI from the pic. My CEL wold go off in trafic from sucken in bad air from peoples exhaust pipes. I would just have to reset my
ecu to fix this problem.
BTW, you might want to put some carb clamps (small band clamps) on your breather tube comming from the air intake. This would help reduce any vacume leaks in the future.

 

[awdtalontsi1992]

The does appear to be the idle adjustment screw. Not being a 420A man I don't know th exact procedure for adjusting it. However I would recomend you pick yourself up a Haynes or Chilton manual. They should tell you how to adjust it. You should try to adjust it so your car idles at 750rpm. To reset the CEL diconnect the battery for 15 minutes. This should reset the ECU.

 

[Slammed0]

Cool thanks guys. Ya I got the Check Engine light off. It was a vacuum leak. But just knowing that my dad messed with that I was hoping it wasn't throwing off the ECU. Seems to be running fine. I wish I knew the EXACT rpms.

 

[WMD]

well i just consulted my chilton and it says the CEL will light if the car does not idle within 200 rpm of the factory set idle. It is 800 rpm btw. I just wanted to say this for furture ref. to help any 420a out.

 

[Slammed0]

well i just consulted my chilton and it says the CEL will light if the car does not idle within 200 rpm of the factory set idle. It is 800 rpm btw. I just wanted to say this for furture ref. to help any 420a out.

Excellent. Much appreciated!