Car: 1997 Civic
Engine: B16A
ECU: OBD2a P30 (from a Del Sol VTEC)
Mods: AEM CAI/Apexi catback
Other notes: Timing belt, water pump, tensioner, spark plugs, wires, distributor cap and rotor, injectors, and fuel filter all replaced within the last 2000 miles

Ever since doing my swap, I have been chasing a few issues with my car. I've been doing research and I believe they are connected, but I would like some help to see if my thoughts make sense.

When the car is fully up to temperature and I am on throttle, it will make a ticking noise. I believe this is detonation, but I am not sure. I am going to pull the plugs soon to check them out. From what I have read, detonation is caused by a lean condition. The lean condition could be a result of improper octane (I always run 93) or excess air.

This leads me to the IACV. Ever since completing the swap, the car has not idled correctly. It will do the typical surging from ~1000 to ~2000 and anywhere in between. I have tried the factory procedure to "relearn" the idle to no avail. I searched for vacuum leaks and could not find any. I believe the problem is the IACV because if I unplug it while the idle is surging, the surging will stop and the idle will even out to 1000+/-50, close enough to the factory spec for me to believe that the IACV is the only problem. I have not yet tried to clean the IACV, but I plan to this weekend.

I guess my question is does this make sense? Does the ticking noise I described sound like detonation and if so, could it be related to my surging idle and more specifically, the IACV?

Would a good test be unplugging the IACV and driving around to see if the ticking noise stops?

Let me know what you guys think. Thanks.

 

Remove the IACV and adjust the idle using the screw on the throttle body and plug the appropriate holes. Take it for a spin and see if the ticking sound persists.

Does it tick while idling normally though? LMA's could be an issue too... what does your exhaust fumes look like? Black? White?... checking the plugs would be a good starting point before tearing into things.

Also are you 100% sure your vacuum hoses are attached in their correct spots?

 

I'll try that with the IACV this weekend.

It does not tick while idling only up to temperature and on throttle. I'm not sure about the exhaust fumes. The color looks normal. Occasionally, they will have a weird smell. The best way I can describe it is it kinda smells like sulfur.

I am 99% sure my vacuum hoses are hooked up correctly. The only one that I am unsure about is a hose I ran from the nipple on the top of the throttle body to the evap canister. I wasn't quite sure how to hook up the evap system, so I just replicated the system from my D16 and the nipple on the throttle body was the only available vacuum port.

 

Sulfur or rotten egg exhaust usually indicates a problem with the catalytic converter.

I'm assuming you are using the header and cat from the B16? I'm thinking the cat might be partially plugged and so when you go WOT the cat backs up the exhaust enough to cause issues and the smell.

Cleaning the IACV is good too for the idling issues.

 

The header is the stock B16 one. The catalytic converter is a magnaflow high-flow one. It has only smelled like that once, maybe twice. It does not seem to be a common issue. I'll check it out though. Thanks.

 

Another issue that I'm having and forgot to mention earlier is lurchiness. If I am driving the car and it gets up to temperature (thermostat open) and then I turn it off and restart before it cools down (this happens all the time, for example going to the store or post office - I would say anytime within 45-60 minutes) it will become very lurchy when driving. When starting from a stop, I will give it some throttle and the rpms will drop while I hold the pedal constant. If I do not increase the amount of throttle, it will stall. Once moving, it is impossible to maintain a constant speed (I'm always accelerating), because the act of easing off throttle is especially violent. Every time I apply or come off the throttle, it feels like I violently stabbed the throttle and as a result the ride is very lurchy. The ride is much like the first time someone tries to drive a manual transmission vehicle.

I have a feeling this lurchiness is related to the ticking noise and the surging idle.

I can replicate all of these conditions 99% of the time. The ticking starts the second the car reaches proper operating temperature (on throttle) and will remain until the car has been shut off and cooled down.

This afternoon, I had some time to test the IACV. What I did is as follows:

I unplugged the IACV and tried to start the car. It did not start, as expected so I plugged it back in and started the car. I drove around until the car reached operating temperature. As soon as temperature was reached, the ticking began. I pulled over and the idle was surging (as it always does). I unplugged the IACV and the idle stabilized to 750. I tried to drive it around the block, but this was basically impossible without the IACV. I pulled over, plugged the IACV back in. I restarted the car (to clear the CEL), as I pulled out, the lurchiness began. It, along with the idle surge persisted until I got home and shut the car off. Interestingly, the ticking noise was not present (I am not sure if this is a common theme, but I will confirm tomorrow). I plan to pull the plugs tomorrow or Sunday to check out their condition.

Any ideas or similar experiences? I've about had it with these problems. I've been trying to diagnose them since August with no luck. I might take it to a shop next week and see what they have to say.

 

Have you checked the mechanical and ignition timing?

 

Mechanical timing is correct. I have not set the ignition timing. I was waiting until I got the idle stabilized before I set it. Do you recommend setting the ignition timing now?

 

Jump the service connector and then have a buddy keep the idle speed at spec while you check/adjust the ignition timing.

 

Thanks for the info. I'll set the ignition timing and pull the plugs out then get back to you guys.

 

I was really busy this weekend. I didn't have time to set the ignition timing, but I did get a chance to pull the plugs. All four:

http://www.flickr.com/photos/64248054@N05/11919443264/
http://www.flickr.com/photos/64248054@N05/11918988145/
http://www.flickr.com/photos/64248054@N05/11919867416/
http://www.flickr.com/photos/64248054@N05/11919870686/
They look just fine to me. Hopefully I will have a chance to set the timing tomorrow.

 

Updates...

First, I made a video of the ticking (ignore the surging, the video was made yesterday). It was hard because the mic on my phone isn't that great, but I think you can hear it in part of the video.


If you listen carefully, you can here the ticking once I start moving. You can hear it start when I come into the throttle in 4th around 31 seconds in. In the video, the ticking sounds kinda soft, but it is more pronounced in real life.

Today, I pulled the IACV out cleaned it. I let the insides soak with degreaser for an hour and sprayed it all out with carb cleaner before reinstalling. This solved the idle issue and I believe the lurching issue (although I have yet to fully confirm this part). I'm not sure how long this fix will last, but it works for now. With the idle sorted, I was able to set my ignition timing.

Bad news, ticking persists. I no longer believe it is caused by a lean condition due to the condition of the plugs and the fact that the idle is relatively normal now.

Any ideas what it could be?

 

Anyone?

 

Have you checked the valve lash?

 

I have not checked it. Unfortunately, now that I am back at school, I will be unable to check it until I come home. Would it be possible for the valves to make noise only when the engine was warm?

 

Are you sure that's under the hood? In the video it just sounds like something rattling like dash parts or door panel or even exhaust heat shield sort of thing. Certain RPM resonates and causes something loose to rattle.

If you can reproduce it with the hood up and your head under the hood, you should be able to narrow down which side of the motor it's on and general area it might be from.

 

IACV would not cause a lean condition. If it's idling at 1000 with the iacv unplugged you have a problem. You should be able to get it down to 500ish rpm with iac unplugged. Try closing the idle screw on the throttle body. If not that and there is no vacuum leak you will want to adjust the throttle stop and recalibrate the tps.

 

The ticking is definitely under the hood. I've got plenty of rattles (and that is probably what you are hearing in the video), but it is a distinctive noise that corresponds to throttle position.

I would look under the hood, but the engine does not make the sound at idle. You can only hear it when the the engine is at proper operating temperature and you are on the throttle.

I'm fairly confident that the engine is not running lean after pulling the plugs. 1000 was a rough approximation of what the idle was like when unplugging the IACV. My main point in typing that was to show that the idle did indeed stabilize when the IACV was unplugged. After cleaning the IACV and adjusting the idle screw, it will now idle correctly.

The ticking, however, persists.

 

Have you yet adjusted the ignition timing with a timing light?

 

I didn't specify earlier, but yes I set the ignition timing with a timing light.

 

The sound quality of your video is poor and therefore not very useful.

As mentioned, check the valve clearances and inspect the exhaust heat shields.

 

Thank you for the tips. I'll keep this thread updated with my findings.