Recently I performed a lot of work on my engine D16Y8. (timing belt, headgasket, whole bunch of other gaskets). After putting it all back together it was idling high. After replacing the IACV and messing with the idle valve I realized I left the cruise control vacuum hose unplugged that was giving me my vacuum leak. After fixing that I was able to get the car back to a somewhat normal idle, 700-900 rpm. Now I'm trying to get my timing right, but when I have my SCS connected it idles at around 1400-1600rpm. I noticed on my scan tool the fuel remains in open loop when though the engine is warmed up. Every once in a while it would close and my idle will drop slightly to about 850-1100 but only for a few seconds. I tried using a different ECU but same thing. How important is it to have the scs connected when adjusting your timing?

 

What car? Add this information to your post.

Post the CEL codes and adjust idle speed as per service manual instructions. See FAQs sticky.

 

Make sure there's no air in the cooling system. That can cause false readings from he ECT. Check the connections to the ECT sensor and measure sensor itself with an ohmmeter. If the ECU thinks the engine is cold, it will idle higher.

Timing cannot be adjusted without the jumper in because in normal mode, the ECU varies the timing as part of its control program.

 

Sorry. It's a 96 civic ex d16y8. No CEL codes and I adjusted the idle speed per the service manual. But it also states to make sure your timing is right lol. There is no air in the cooling system and the ect reads normal when viewing it on my scanner. Also the radiator turns on when it's supposed to. Like I said above, for some reason the fuel system only stays in open loop

 

Post the exact procedure (or diagram) you used and what the outcome was.

 

I check all the items on page 11-191 and followed the idle adjustment on 11-221(I have a auto). My car idling at 730 with no load. but when I start it with the scs jumped, it idles at 1150. I tired a different ECU and the same thing.
EDIT:
Today my fuel system is staying in closed loop but its still idling at 1150.

 

Page 11-191 does not describe the idle adjust procedure.

Which idle adjust procedure did you use on pages 11-220 to 11-223?

 

Page 191 states

"When Idle is out of specification and scan tool does not show codes, check these items"

I tried checking all those items and everything is good. Then I performed the idle adjustment procedure of page 11-221

 

so just screwing around, I unplugged the ECT sensor and allowed the engine to warm up more, after about 45 second the idle dropped to about 800 with the scs jumped. After I plugged the ECT back in the radiator fan kicked in and as the temp dropped my idle increased again. I also noticed on my scan tool that it was still reading a coolant temp even with the ECT unplugged. Is there another coolant sensor that goes to the ECU I need to test and replace?

 

Does you car have an auto transmission? (It's missing in your car information.) If so, describe what happened (details) when you tried to adjust the idle speed.




The ECT fan switch on the thermostat housing has nothing to do the with idle speed.

The relevant ECT sensor is located below the distributor. What temp reading do you get with the scan tool with the engine fully warmed up?

 

I have a automatic.



Even with the ECT sensor below the distributor UNPLUGGED it is still showing me a coolant temp of about 90-120 F. My coolant gauge on my dash is 0. Is there a 3rd coolant sensor I don't know about? When the sensor is plugged in my temp gauge is showing normal on my dash

 

Provide the requested details.


That's a wide temp range. It's meaningless. Is an ECT code thrown when unplugged?

Irrelevant. It's controlled by 1-wire sensor below distributor.

2-wire sensor below distributor.

 

AHHHHH! That'll probably do it. Let me check

 

As you are unwilling to answer questions and to provide requested details, I am locking this thread. See forum Rules sticky.