5559 posts
89 240sx Hatch, the wildcats!
The Mutha Land ca
4-1-2007
Help with odd idle issue.
8:28 PM 8/17/2008
Alrite for some reason my SR starts up fine, vacuum reads good, usually 16-17mmHg at idle. When I drive it drives just fine, doesn't bog or stutter. However when I get to a stop light, the car will idle fine for about 30 seconds, then all of a sudden, the idle drops from 850 to 500(or something close to that area) and it acts as if it wants to shut off.
It also shakes the car. It does this everytime too. Get to the stop, no issue, then a few seconds later, it drops idle, then eventually picks itself up.
-I ran a boost leak test on it, and I fixed the one leak I had and it still did it. -Check my vacuum lines, all are brand new lines. -Cleaned the IACV, and still the same issue. -BOV is recirculated. -Readjusted TPS to make sure and check if its working, it is.
i have the same exact problem! i have also cleaned the iacv, and i haven't done a boost leak test yet, but it wouldn't really make sense to have a boost leak if my engine is pulling good vacuum(22inHg), right? spark plugs are ok, timing is correct, fuel pressure is correct, etc.
every once in a while, the vacuum drops to 17-18inHg and that's the same time my idle drops down to 500 rpms. i know that some ppl say that 17-18inHg is a good vacuum, but if that drop in vacuum is accompanied by the drop in idle, to me, it seems like something isn't right.
i would get bogging/hesitation problems sometimes when i try to cruise at freeway speeds. the bogging starts when i press on the pedal just enough to cruise, but when i floor it, it would speed up ok. this usually happens when i turn my ac on(compressor is bad,possibly stuck?), so i removed the ac belt, and this has reduced the bogging, but i still notice it sometimes(just not as bad).
hey duffman, i see that you're from CA(i assume socal?), and i wanted to know if you did your own swap/wiring or did a shop do it for you? i've been told that the shop i brought my car to takes a shortcut on the wiring to get the car to run. i was thinking maybe the wiring might be the cause of this problem. the reason i think this is because my problem might be related to something electrical(the idle problem occurs more frequently when i turn on ac or just fans).
whoa, just realized that was a long post, lol. i've posted this before, but no one has said they had the same problem as we have.
Hmm, I was thinking about buying a new IACV and puttin that in. But I'm going to be swapping MAF's this weekend with my friends to see if that fixes it.
Yea I'm from socal =] I did the swap myself, but the guy who did my wiring was really good, so I doubt it has anything to do with it. I got it done from a local.
I have the same exact issues, iv even posted people about it (idles stedy at first stop ,then a rpm dip and 15-17 vac...was told its a leak, tested the system, cant find it....kept it moving. does it still run...yes is it still annoying as hell ..... yes ,just waiting for someone to comment in and tell yous that its cause your bov isnt recirculated, but wait, you said it is didnt you
shame on u, when u step too , the old dirty blacktop/ new york zoo./ [
did you figure out how to fix your idle problem yet?
i think i actually do have a boost leak that might be causing my car to idle weird. today, i just noticed that my turbo wasn't spooling like it used to. it would be at around 2 psi @ 2200 rpm and it would stay at 2 psi until 3000 rpm before the boost goes up again. so does this seem to be a boost leak? if so, it might be possible that a very small boost leak is what is causing these idle problems and we don't notice it until it starts getting worst...well, that's my guess, haha.
did you figure out how to fix your idle problem yet?
i think i actually do have a boost leak that might be causing my car to idle weird. today, i just noticed that my turbo wasn't spooling like it used to. it would be at around 2 psi @ 2200 rpm and it would stay at 2 psi until 3000 rpm before the boost goes up again. so does this seem to be a boost leak? if so, it might be possible that a very small boost leak is what is causing these idle problems and we don't notice it until it starts getting worst...well, that's my guess, haha.
when my first sr car did that it was the turbo coming loose at the manifold. In my experience, anytime I have had a leak in boost the car sputters, and is worse when you are driving and modulating the throttle....
when the turbo starts to come loose, it doesn't do that as bad, it just spools really poorly because its not scavenging exhaust well...but it still is getting enough that it can make a little pressure.
so I would just check to be sure. If its loose you don't want it coming completely off while you are on the road somewhere without tools.
