Low idle after car warms up

buckwheat

New Member
LOOKING FOR SOME ADVICE!!!! I have a 97 Civic EX with the D16Y8. The car runs fine until it is warmed up. Then idles low, like around 250 – 300 RPM. I don’t notice any power loss. I have checked for vacuum leaks and found none. It has a fresh tune up consisting of NGK plugs, 8mm Plug wires, Cap and Rotor, Fuel Filter and K&N air filter. Everything is stock, but I still need this motor for at least a year. I am currently working on the new motor, B18C GSR, LSD Hydraulic Tranny S80, ECU (P72), AEM Cold Air V2 System (Titanium), T04E Turbocharger, but that is a slow process. I am running out of ideas. Any assistance would be grateful.
 

TokyoSkies

Boost Junkie
Registered VIP
5+ Year Member
Loosen the dizzy bolts (just enough to rotate the dizzy a little bit), turn the car on, have someone sit in the car and monitor RPM's at idle (when it's warmed up), while you rotate the dizzy a bit. Your idle will fluctuate. Get it to about 800RPM warm idle, then tighten the dizzy down. If that doesn't work, there's an Idle Adjustment Screw near the throttle body. Use a flathead screw driver, and adjust it with the car on.
 


RonJ

Banned
First off, a vacuum or intake air leak would cause a high idle, not a low idle.

And please don't adjust the idle speed by turning the distributor. If you think your ignition timing is off, check it with a timing gun. But first tell us whether any CEL codes are thrown. Have you cleaned the IACV?
 

buckwheat

New Member
No i am goin to clean my IACV and FITV then go from there
I dont know about codes i will check that too.
 


buckwheat

New Member
OK I cleaned the IACV and throttle body and the idle went lower. To the point where the car would die at a stop light. I adjusted the idle screw. I had to take it out little over a turn. Both gaskets were good so I reused them. I am going to try and get a hold of a timing light and check that. Any other ideas?
 

00CivicSiR

Em1 Crew
Hey for one check the actual idle with a scan tool or the tool that hooks on your spark plugs, mine was reading 400 rpms on the tach but it was actually idling at 712 or so rpms on a scan tool when I checked it, I thought I had a super low idle but it turns out the tachometer was just off haha (this is on a 2000 si)
 

buckwheat

New Member
Stock D16y8 as stated in the beginning on the post. So the ECU is a P2P. CEL is not on. I am the only one who works on my cars. the tps was not messed with. what i did yesterday was clean the iacv and throttle body and adjust the throttle cable. and the low idle was worse then before. The tach may be a little bit off but it almost dies at a red light.
 

RonJ

Banned
Does the CEL work?

Manual or auto transmission?

Does the engine otherwise run fine?
 

scarhead92

New Member
Registered VIP
5+ Year Member
RonJ said:
Does the CEL work?

Manual or auto transmission?

Does the engine otherwise run fine?
Click to expand...
I'm with K-PAX up there. is your throttle cable getting stuck somewhere? if you blip the throttle will idle momentarily come up? can you pull gas pedal toward you with your foot and kill it? did you put idl screw back in original place since the idle is worse than before?
 

buckwheat

New Member
Cel works Its a manual trans. Runs fine other then the low idle. On a cold start up its runs about 2100 RPM but once warmed up it runs about 850 RPMs.
 

RonJ

Banned
buckwheat said:
Cel works Its a manual trans. Runs fine other then the low idle. On a cold start up its runs about 2100 RPM but once warmed up it runs about 850 RPMs.
Click to expand...
850 rpm is a high idle speed, not a low one.

Adjust the idle speed exactly as detailed in the diagram.
 

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buckwheat

New Member
The throttle cable is fine. all i did with the throttle cable was take the slack out of it. the prob accrued before i cleaned the iacv throttle body and tightened cable. i adjusted the idle screw to bring the RPMs up so my car would stay running AFTER i cleaned and tightened
 

buckwheat

New Member
Thats what it is at right now after i adjusted the idle screw i need to tweak it a little but i needed to get to work and didnt have time. but according to manuals 800 rpm for a manual it recommended
 
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