99 Civic EX Idle Problems
 

Tried to avoid posting by doing research and troubleshooting for a couple months, but no go. Here it goes.

Symptoms: Idle fluctuates between 400 and 1100. I have not noticed a pattern. It does not go up and down quickly, normally I'll pull up to a stop light and it will drop to 4-500. Sometimes it will idle fine at 800-1000. No issues when car is cold. NO CEL.

MUTE YOUR SPEAKERS, SORRY. @ 14 seconds is me tapping accelerator to demonstrate idle settling back in.


Car: 1999 Honda Civic EX Coupe
-Bought it about 2 months ago. Didn't realize that it didn't have a y8 block when I bought it.

-y8 head // y7 block // y8 intake manifold // p2p ecu
-aftermarket short ram intake
-Manual
-Everything else is stock as far as I know, though I will say I know it was owned by a college aged kid who had leds installed under the dash, etc - so who knows if there are aftermarket pistons in there or something along those lines.

Things I've tried:

-IACV from junkyard - cleaned, installed, same symptoms
-Cleaned original, stuck it back in, same symptoms

-Sprayed down intake area (+ other vacuum leak sources) with carb cleaner - Idle did not change

-Bled coolant system - Even though I don't understand why, but this was recommended by several people.

-PCV (not OEM) - same symptoms. I'd rather not pay for $30 for one from Honda, I don't believe this is it as the symptoms didn't change. Though I will say the old PCV was pretty gummed up and I could barely hear the rattle.

-Turned up the idle screw very little, didn't seem to make a difference. Will probably turn it back.

-probably more that I'm not remembering.


I'm trying to fix this myself and minimal cost. Ideas?

Re: 99 Civic EX Idle Problems
 

You may have read this post when during your searches, if not it list a lot of possible solutions: http://www.clubcivic.com/board/showthread.php?t=101065 I am pretty sure that a '99 does not have a FITV.

Also, have you tried resetting your ECU: http://www.clubcivic.com/board/showthread.php?t=1180 and ignition timing: http://www.hondacivicforum.com/forum...ustment-16210/

Re: 99 Civic EX Idle Problems
 

Correct, no FITV. I have not done anything with the TPS, but I have also read in several places that it's super rare for them to go bad. I don't have quick access to one either, or I would have tried. That may be the next step.

A buddy of mine just put a clutch and flywheel (Exedy OE Replacement) in for me as well, he disconnected the battery while he did it - which should have reset the ECU. The problem was occurring before and after.

I have not checked the timing, but to be honest I've never done it before and for some reason it's more intimidating it probably should. Need a timing light as well.

Thanks for links

Re: 99 Civic EX Idle Problems
 

You may want to reset the ECU in this way: http://www.team-integra.net/forum/bl...reset-ecu.html

Resetting the timing seems daunting at first, but it's a 10 minute job once you do it a couple of times. Maybe your buddy can help you if he has a timing light. I kind of doubt that it will improve your idling issue, but it's worth a try.

Another possibility is the valves clearances may be out of spec and need a valve lash adjustment: http://www.civic-eg.com/causeforalarm/D16Y/index.php
Another project that seems daunting at first, but it's pretty straight-forward and there are many DIY threads and videos to help.

Re: 99 Civic EX Idle Problems
 

New tps can be had for 14 dollars on ebay, other than the idle how does it feel through out the rpm range

Re: 99 Civic EX Idle Problems
 

Does the CEL work?

How did you bleed the cooling system?

Does your Y8 IM have the FIA system?

Have you tried to adjust the idle speed as per the service manual instructions?

Re: 99 Civic EX Idle Problems
 

Reset the ecu as instructed, same symptoms.

I believe that dude has a timing light and knows how to do it. We're fixing a hole in my floor and putting H&R Springs in so hopefully we can fit it all in.

Re: 99 Civic EX Idle Problems
 

Check engine light works. I pulled the IACV plug while it was running awhile back for troubleshooting - it tossed a code.

There is no bleed screw on this cooling system, so I basically just ran the car for 10 minutes with the cap off. I don't have one of these

I don't believe it has the FIA system, I think they only put it on a few models in the 94-95 area? I could be wrong, is it common?

If the idle was just low, I would worry more about trying to adjust it. It's intermittent. I suppose it's worth a try but I don't just want it to be intermittently higher.

Re: 99 Civic EX Idle Problems
 

Currently, when you turn the key from off to ON(II), does the CEL illuminate and then turn off after 2 seconds?

For bleeding, top off the coolant in the radiator and reservoir, open the valve for the heater to max heat, and idle the engine until the radiator fan turns on twice. Having the car on an inclined driveway with the front higher than the rear also may help.

The fuel injector air (FIA) control system is specific to the 99-00 IM of the D16Y8 engine. It can cause intake air leaks in some cases.

The idle speed must be adjusted exactly as described in the service manual or the procedure won't work.

Re: 99 Civic EX Idle Problems
 

Thanks Ron! You are honestly the most helpful person I've come across around here.

I do have the FIA control system and it is partially blocked because of the installation of the short-ram air system. The "T" part is blocked (Part #24 Below). I'll upload actual pictures soon.

http://i215.photobucket.com/albums/c...ing/670041.png

Checked radiator and topped off reservoir. Let car idle for 20 minutes+. Both radiator hoses hot, yes - even lower. Temp gauge shows normal. No fan. 20a cooling fan fuse NOT blown. wtf?

EDIT: To be clear: This problem was occurring before the short ram intake was installed. This makes me think that the plugged end should not be the culprit of these problems. But wtf? No fans?

EDITx2: If I short the fan switch plug the fan turns on. Looks like I need a cooling fan switch on top of all this.

EDITx3: Apparently you just have to let it idle forever or bring it up to 2-3k to get the fan to kick on. Seems to be working.

Re: 99 Civic EX Idle Problems
 

http://imgur.com/Pi7OBFW

http://imgur.com/Pi7OBFW

Apparently the picture wont display without clicking on it because it's too big to imbed?

Re: 99 Civic EX Idle Problems
 

Hey op, when your car is fully warmed up and idling, right when it does that funny idle action where it runs high then it drops down, try checking out the wires going to the IACV and push them into the connector more and see if the idle straightens out...

I've been noticing a common occurrence where people will clean up their IACV but they'll have idle issues and I think it's tied to the fact that the one or more of the wires in the connector for the IACV get loose causing the messed up idle. I've seen this issue at least twice now and it won't pull a code for this.

Re: 99 Civic EX Idle Problems
 

You replaced the IACV with one from the scrap, but the problem persisted. I would suggest the next time this happens you unplug the IACV and see what happens. If the valve is at fault the car will begin to idle normally, if not it will continue to fluctuate. Also I would flush the coolant again, so as to get rid of any possible air bubbles that may be working there way through your system and causing your issue. Good luck
I tend to undo the small coolant house that feeds into the throttle (highest point of the system) when bleeding the air, also try to have one of those funnels that attaches to the radiator and let it run for 10-15 min with fluid in the funnel so it can get rid of air bubbles as well as take in fluid to replace it.

Re: 99 Civic EX Idle Problems
 

If the car has a 3 wire IACV, disconnecting the IACV for testing doesn't exactly work.

Re: 99 Civic EX Idle Problems
 

Thanks for the help guys.

I tried searching for more vacuum leaks, but I don't think that's the problem - it will normally idle high if there is a leak, correct? Also, If I plug the lower IACV hole in the TB the car wants to die - so I think that's more evidence that it's not a vacuum leak. and because this was mentioned: The car dies if I pull the IACV plug.

Also, I tried the proper idle adjust by the book with the ECU reset, etc

I put the car on an incline and got the fans to turn on a couple times. I did have to bring the RPMs up to 2-3 for a minute or so to get the fan to turn on. Let idle for about 10 minutes.

I'm going to set the timing this weekend. I don't see it fixing the problem, but it can't hurt. Might try getting into valve clearances and stuff too, but like I said earlier - that might be a job that's over my head.

One thing I will note, the car seems to idle better(higher) if I create a vacuum leak. Idk if that tells you anything.

Re: 99 Civic EX Idle Problems
 

Post the full code of your ECU - the numbers that follow P2P.

The Y7 block doesn't have a knock sensor. Has one been installed?

Was the heater valve on the firewall wide open when you bled the cooling system?

Below is the proper method for adjusting the idle speed for your engine/transmission. You must connect an external tachometer because the one in the cluster is inaccurate.

Re: 99 Civic EX Idle Problems
 

Chalky white plug (all 4 look similar)
http://imgur.com/UDsanXX

ECU
https://i.imgur.com/Zg5haXY.jpg

Re: 99 Civic EX Idle Problems
 

Manual Transmission.

I do not know about the knock sensor. Sorry if this is a noob question but Idk where it is, do I have to take the head off to check ?

I didn't actually check the valve by the firewall, but it was blasting heat inside my car. I'll try again, I guess - but I find it hard to believe that air in the coolant system is causing this problem.

I followed that idle adjustment page you attached to a T except I don't have an external tach. :/ EDIT: I did not check timing. Trying to get timing light for this weekend

Re: 99 Civic EX Idle Problems
 

ECU is fine.

Replace those old plugs, as well as the plug wires, cap, and rotor. Then adjust the ignition timing.

Re: 99 Civic EX Idle Problems
 

All OEM ?

Re: 99 Civic EX Idle Problems
 

It's a 1-wire sensor glued to the rear of the block near the oil filter.

That's fine. Air in the cooling system can definitely cause the kind of idle problem you are having.

You MUST use an external tach because you can't possibly set the base idle speed to 450 rpm without it. And did you unplug the IACV for the procedure?

Re: 99 Civic EX Idle Problems
 

OEM would be best. Definitely buy NGK plugs (see owner's manual) and OEM wires.

Re: 99 Civic EX Idle Problems
 

I did unplug the IACV for the Idle Adjustment. I'll have to find a tach.

Re: 99 Civic EX Idle Problems
 

A tach, or a code reader that also reads live data, will work. I use an Actron scan tool. You may be able to rent (free) such a code reader from an auto parts store.

Re: 99 Civic EX Idle Problems
 

Ah, good thinking. I have access to one of these: