Hey guys (and gals) I found this board while trying to figure out whats up with my wifes honda.
There seems to be alot of knowledge here, so maybe you can help me.

She has a '97 4 dr Honda Accord EX. 5sp manual, 154K miles. Her original complaint is that the exhuast is rattling. Upon closer inspection, the reason the exhaust is rattling is becuase her idle is extremely rough.

When you first start it up, it idles at just under 1k rpm. Nice and smooth. then once it is warmed, it drops down to about 700rpm. From what I have read, I think this the correct idle speed, but I may be wrong.

The real problem is that the idle is very rough, alot of shaking (which has broken an exhaust hanger i think). If you lightly press the gas pedal, and bring the idle up to about 900, everything smooths out. It does not hunt, or surge, or have a high idle, so I am not sure that things like the AITV are the problem, but I really have no idea. All vacuum hoses appear to be in place, I have never replaced the plugs and wires since it was in our possesion-90kmiles. I torque checked the motor mounts, that does not seem to be the problem

I tried doing a search, but everything I have found is for surging/hunting idles, and that isnt helping me. Can any one give me a few ideas to look for?


thanks

 

Where you say that you have not changed the plugs and wires in over 60K miles. I would give a tune up a try. Plugs, Wires, Cap & Rotor, Air Filter, maybe a fuel injection cleaning as well.... never hurts

Any one with any other ideas

 

Clean IAC and FITV....there's a thread somewhere on this...let me find it.

 

https://honda-tech.com/zerothread/1844067
Easy fix if this is the problem, you only need a few bucks in supplies, takes 20 minutes.

 

thanks guys.

as for replacing the plugs, wires, cap and all. that was my first instinct, but
thats about $100 worth of parts, and I need to be sure that would fix it- funds are tight right now.

I had also read the thread about cleaning the IAC and the FITV, but I wasnt sure if that was the right direction. my impression was that those really caused the idle to surge, or hunt as its been called here. PLus, I went out and looked, and one of those is pretty close to the firewall on the back of the intake manifold, and its a blind area trying to get it loose and remounted. so again, before I went and dived into it, I needed to be sure.

so, you really think I should clean those 2 assemblies?

 

OK then, cleaning out the IACV and the FITV is the budget way to narrow down this problem that's for sure. All it costs is can of throttle body/Carb cleaner and 2-3 hrs of your time.

The IACV is pretty tight in there but you can get 10mm socket or wrench back there to crack the bolts. Where the intake is aluminum you can usually turn the bolts buy hand after that. Getting them back in is a bit tricky, a small mirror will help so you can see in behind the intake manifold to line it up.

 

Sounds like some kind of misfiring rather than a surging idle. (OTOH it's not a bad thing to clean the IACV & FITV.)

New spark plugs (NGK) are cheap - try that. If you see oil down in the sparkplug tubes, you can search around for threads on that topic (sorta common).

Two ways for sparkplug wires to fail - check them
1 - excessive resistance, measure with ohm-meter
2 - insulation breakdown, watch for arcing in the dark.
Dealer plug wires are good, but $$ don't replace them unless they fail here.

ps... Actually, that car is OBD-2 so it *should* detect misfiring & show the check-engine lamp. So what about mechanical rattling?

Look for alternator/AC/PS belts that shake as they spin. Alternator bracket loose & wobbly? Turn off AC completely - vibration still there?

Finally - see if you can get your hands on an external tachometer. Maybe the one in the dash isn't too accurate way down low?

How about the EGR stuck open? Rough idle, but it should throw the check-engine light.



Modified by JimBlake at 12:36 PM 5/2/2007

 

I had the same exact problem in my accord. Couldnt figure it out for the longest time, tried everything you guys said here. What I found out was my throttle body was filled with so much **** it was unbelievable. cleaned all of it out real good and it started idling fine, and has been good ever since. Maybe you have the same problem, wouldnt hurt to check it out

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by accord2021 &raquo;</TD></TR><TR><TD CLASS="quote">Clean IAC and FITV....there's a thread somewhere on this...let me find it.</TD></TR></TABLE>

that and check the heatshields for cat and exhaust

 

you know, i had the same problem with my 92 accord and i decided to check the distributer cap for the heck of it. when i inspected it, it was pretty bad. after i replaced it, the problem was solved. try the distributer cap, you never know. 75K miles later, now, i have a rough idle again, but i'm pretty certain its the IAC valve.