Idle's Funny

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randerson165

Senior Member
I just replaced the head on my SOHC civic. I think I have a vacuum leak somewhere, I can hear a small "shoooo" sound that I didn't hear with the other head. Also, my idle goes from 2k to 1.5k and back to 2k repeatedly. How can I find the vacuum leak ? I torqued the intake manifold down really good too.
 
I like to use a can of carb. cleaner and spray it around the IM or wherever u hear hissing noise. Listen for idle changes when u spray it, this is usually the sign of vacuum sucking in the cleaner. As for the idle, it's usually normal at start-ups of a head job, but if u say u got vacuum leak, then that's probably your main problem. Good luck!!! and toast to that 6 pack...
btw, remember to bleed your head, turn on your heater at full blast to let coolant circulate and get rid of trapped air and make sure the cooling fan is on. :sleep:
 
could bleeding my head help my problem ? how long do I want to bleed it for ? I sprayed some cleaner on the IM right on top behind piston 3 & 4. It idled down, I tried torquing the bolts more but If I turn any more, I might strip the nut. Can I spray some kind of sealer on the outside ?
 
Bleeding the head is just to remove trapped air in your system, you'll know it's done once no more air bubbles comes out the bleeder port. Once the fan comes on, that usually tells me all of your cooling systems are operating as it should, ie; CTS, thermostat, relay, etc. I don't know of a spray for the outside and I doubt it would resolve your problem because an IM leak is usually the case of an uneven torque. Besides it'll look mickey-mouse if u apply some silicone on the outside anyways. This might be a bitch, but I'd suggest u remove the IM and there's a copper gasket spray in a copper can that I love to use that u can spray on the gasket real good and it's very sticky. It's always does wonders for me. I think 3M makes it and u can purchase that at Kragen or Pep Boys. Good luck!!! BTW, are u doing this while we're writing?
 
take the time to fix it right and remove the im and replacce the gasket and also mak sure you torque the bolts in sec
 
I was running to my car and doing all of these after your suggestions. Thanks...

I did torque the bolts in sequence. Can I use the same gasket thats on there when I replaced it last time. I only have 3 hours on the new gasket !!! Can I just pull it off and apply that copper spray ?
 
Is there a special tool or some trick to getting of that one nut on the bottom of the IM ? Its a bitch to get to !!!
 
Sorry it took me so long to reply but actually there is a better tool that u can use. I own mostly them Snap-Ons and Matcos but u can reference and have the idea on other brands. What works best for me is a long 1/4" swivel extension with a 12mm magnetic socket where it would reach far enough just to pass the end of the manifold. Personally if u haven't scratched the gasket or damaged it in any way other than torque, then I would say go ahead and reuse it with the copper gasket spray. Good luck!!!
 
I talked to a honda tech and they said they don't think its a vacuum leak.

When I put my head back on, I took the Adjustable cam gear off my old head and put it on my new head. I didn't set it at 0 degrees when I put it back on and so they think its off a couple of teeth and thats why its "hunting" for an idle.

Does this make sense ? Can't I just loosen the allen bolts and turn the cam gear to adjust it ? I tried that and it didn't help.

How do you adjust a cam gear ?
 
What I would suggest is setting your cam gears back to zero and start over from there. If u have a timing gun it would be much easier to see how off you are. You can adjust (advance or retard) your timing by moving the distributor back and forth. Be very careful when trying to adjust your cam gears as it may cause internal engine damage. I highly doubt that this is your problem but if u have suspicion, get a timing gun and shoot away. BTW, have u try to repair the IM and gasket yet? How can a Honda dealer be so judgemental without even seeing the car. Remember, most of these Honda dealer tech's are just like anyone else if not even worst. They don't rebuild motors like we do, it's all about parts replacement to them. Trust me, I've dealt with them long enough.
 
I had the same problem with my H22. It was idling between 700 and 1500RPM. I tried alot of shit like cleaning the IACV and fast idle valve... Although after cleaning the fast idle valve it got a little better but still not right at all.. It turned out that the idle adjust screw on the throttle body was out way too far and it was leaking air from there. After I gave it a couple of turns, the idle fluctuation was fixed! Now she runs great. So I'd check the idle adjust screw for sure.
 
cool, i'll do that.

the honda tech said he doesn't think its a vacuum leak on the IM becuz when I spray carb cleaner on there I have to spray a generous amount before it settles the idle down. He said that even with a super good seal, a generous amount will eventually get pulled in. So if I sprayed short like (ppssshh) and it settled the idle down then he would think its the IM leak, but since I spray like (pppppppppppssssssssssssshhhhhhhhh) he thinks its a generous amount and there is so much that it is getting pulled in. I'll try the idle adjustment.

When I try to time it, I didn't jump the service connector and I'm not sure it was about 750 rpm's !!!
 
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