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Discussion Starter · #1 · (Edited)
Alright guys... Noob in progress. I have a 1998 Honda civic EX that was abused as a baby so when I bought her she repaid me by blowing a motor. I got my head and block rebuilt at a machine shop but did the tear down and reassemble myself. I'm no mechanical expert or anything but I understand and do way more than the average 18 year old car enthusiast. anyways. my problem is if the ECU is reset and all sensors and plugs are connected, I have a bad surge on my idle. it's a thing with these cars, I know. "just clean this or do that." I've done it all and the only solution is unplug the MAP sensor and run my daily driver without it. I get around 20 MPG highway in my two door civic this way... I would like this fixed because it isn't good to just keep going sensor-less. I have been told by a few experts and master techs that it's my IAC valve and it is on the back of my intake manifold. To bad it isnt there huh?? Where is the IAC valve on a D16Y8 in a 1998 Honda civic EX??? If there isn't one could my 1000 RPM surge be caused by the FITV instead?? I didn't burp my coolant system from the get-go and I read in my Haynes manual that this system can go haywire when air bubbles or low coolant occurs? Who can help me finish this rebuild fully to get me started on small performance upgrades??!!
 

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To me it sounds like they are talking about the PVC valve.



I hope that helps. I had a 95 civic d16z6 and it was doing the same thing I just replaced this part it floats on the hose in the d16z6 this image is one I found for a y8
 

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1 not beelding your coolant system will can give you hell with your idle (fitv and uneven flow). and not bleeding can make you overheat and blow another motor
2 i just looked up the y8 in honda i assume sence it not on the back of the mami you have an automatic manifold. then the IAC will be on the left side on the mani behind cyclinder 4.
3 FITV can casue if it idles good cold but hot does a 1200-1500-1200-150 idle to jump around. bleed the coolant and then if it still gives you crap tighten the white plug inside.
im done spoon feeding for the nite.
 

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92-00 civic the iacv location are in the same spot. It has to be there you just dont know where it is.

Question, how the heck did you manage to put this engine together without knowing these parts?
 

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thats for the help.

I have flushed my coolant once before and I never run it low. many of the Honda mechanics I know around inc have all told me it is bolted onto the back on the manifold near the firewall but I don't have that. I know what all the parts are but I just was confused why they were telling me it's in a spot where's nothing is. and building a motor is not hard at all and working on them is easy as well. it's building a performance motor that is where skill and knowledge is used. that's how I built a motor "without knowing the parts." I'll upload pictures after work today to show you guys what I really mean. my other motor I bought had the IAC valve on the back of the manifold but my intake is just a smoothed off, machined flat surface. that is why in asking.
 

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To me it sounds like they are talking about the PVC valve.



I hope that helps. I had a 95 civic d16z6 and it was doing the same thing I just replaced this part it floats on the hose in the d16z6 this image is one I found for a y8
The hose going from the PCV valve to the intake is fully collapsed after the motor warms up. what does this mean??
 

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ej8
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I cant find pictures or a manual or anything that shows an intake manifold like mine. it is extremely similar but the back and throttle body is different.
Pull out the cell and take some pictures.
Also any check engine lights?
And the y8 auto has the iacv different.
http://www.d-series.org/forums/engine-building/128966-drilling-holes-iacv-y8-auto-mani.html
Its under the throttle body. You probably think its tge fast idle valve, but its not because y8 dont have them.


Also vacuum leaks can cause this problem.
 

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The hose going from the PCV valve to the intake is fully collapsed after the motor warms up. what does this mean??
Replace your pcv vavle. Its probably stuck close and the vacuum from the manifold is closing the hosr. Id also replace the hose as well.


Sorry dso replyed via cell could edit old post ^.
 

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Discussion Starter · #11 ·
thanks so much!!

Thanks guys! I'll give it a go. the Haynes manual called that the fist idle thermo valve and the experts called it the idle air control valve so I was confused. I checked for vacuum leaks and there weren't any. I also flushed and filled my coolant and I don't run low oil or anything. I bought this car used and the previous owner didn't take care of it at all so I drove it for a while and the head gasket blew and it overheated and dropped rings so I spent six months rebuilding it all on a minimum wage pay... it's all fine now just has horrible gas mileage and I have been driving this motor for about 2000-2500 miles.

when it's all plugged in and operating right, there is no CEL... just a surging idle. after this is fixed then I'm going to save up and slowly work my way into some performance mods... I'm trying to work my way out of noob repair man and into intermediate status! lol:)
 

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looks like the DSO guru's already stepped in and [potentially] solved your problem.

i had the same surging idle problem you have, i did everything listed above (minus the fitv since my motor is a y7) and still had a surging idle. i bought a shitty felpro tb gasket from autozone and tried to reuse the iacv o-ring this combination of fails was causing my surging idle. i bought an oem honda tb gasket along with a new iacv o-ring and my now idle purs at 700rpm.

good luck, i hope your fix is as simple as mine.
 

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1 not beelding your coolant system will can give you hell with your idle (fitv and uneven flow). and not bleeding can make you overheat and blow another motor
2 i just looked up the y8 in honda i assume sence it not on the back of the mami you have an automatic manifold. then the IAC will be on the left side on the mani behind cyclinder 4.
3 FITV can casue if it idles good cold but hot does a 1200-1500-1200-150 idle to jump around. bleed the coolant and then if it still gives you crap tighten the white plug inside.
im done spoon feeding for the nite.
THIS!!!! tighten the plastic plug inside your fast idle valve and call it a day.

Thanks guys! I'll give it a go. the Haynes manual called that the fist idle thermo valve and the experts called it the idle air control valve so I was confused. I checked for vacuum leaks and there weren't any. I also flushed and filled my coolant and I don't run low oil or anything. I bought this car used and the previous owner didn't take care of it at all so I drove it for a while and the head gasket blew and it overheated and dropped rings so I spent six months rebuilding it all on a minimum wage pay... it's all fine now just has horrible gas mileage and I have been driving this motor for about 2000-2500 miles.

when it's all plugged in and operating right, there is no CEL... just a surging idle. after this is fixed then I'm going to save up and slowly work my way into some performance mods... I'm trying to work my way out of noob repair man and into intermediate status! lol:)
They are VERY different. IACV is on the back of the intake mani, and the fast idle valve is under the throttlebody on my d16z6. Xile mentioned that the y8 has no FITV just an IAC under the TB. some thing to consider
 
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