SoHov

My 1998 LX is having trouble with a surging idle. I ran the codes on it first with the paperclip trick... came back a code 14 (IAC idle air control)

So I checked a bunch of hoses did a few things, it was still throwing a code 14. Then I got out the laptop and ran the codes, it threw the IAC code and a p0108 which is the MAP sensor High. Apparently I've got some sort of problem on my intake.

I swapped the IAC out, swapped the MAP out, checked my vacuum hoses found a couple that were so-so, so i replaced them. It's still surging. The weird thing is... if I unplug the MAP sensor harness, it'll idle down to basically where it should be, then plug the MAP back in, and it stays down. Turn car off/on again and it's back to surging.

Any idea what I can do with this one?

sicones

#1 everyone is going to ask if you have the map and tps harness mixed up
#2 eveyone is going to ask if you checked the wires
#3 almost forgot VACUUM LEAK!!
and pull the battery and let the car idle for like 10 mins after so the ecu can reset, stabilize and idle

SoHov

lol I knew that one was going to come up.... I'm pretty sure I didn't mix up the MAP and TPS harnesses, yeah I know they're the same but they generally line up with where they're going. Just for ***** I'll swap em and see what happens.

Wires.. meaning the harnesses? Yeah I put a test light on but I haven't checked the voltages yet.

I thought of Vacuum leak, hence why I was replacing hoses, But obv it could still be a leaking vacuum. I tried the trick spraying starting fluid around the hoses to check for a leak and didn't find much. Again, that doesn't mean it's not still leaking.

Last night I pulled the batt. cables and then this morning put them on and started it again, it idled.. but at 1500 rpms for 30 minutes and at least 2 fan cycles. I didn't have time to mess with it to see if it was going to surge again.
--I'll try the pulling the battery while it's running, see if that helps. Tnx guye

snatch

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SoHov &raquo;</TD></TR><TR><TD CLASS="quote">--I'll try the pulling the battery while it's running, see if that helps. Tnx guye</TD></TR></TABLE>

I don't think this is what he meant. I think he meant disconnect the battery, then let it idle for 10 minutes after you disconnect the battery and reconnect it. I could be wrong, but I don't see how running the car without the battery is going to solve ****.

You can either unplug the ECU or disconnect the battery to reset the ECU, your choice.

SoHov

Yeah I was kinda wonderin myself, but I figured who knows, mebbe the ECU would reset if the battery isn't in the loop or somethin. I tried that last night, AFAIK it takes like an hour to reset without the battery but whatev.

So that DID have an effect, it reset the CEL and cleared it, and this mornin the idle was steady (no surging) but it was stuck at 1500 - 1600 rpms.

Oi. I feel like I'm never gon figure this out, lol, it's going to be the stupidest **** it always is. There's probably a crack in a vacuum I missed somewhere

snatch

Well if the idle is constant, that's better.

Check the throttle body to make sure it's clean and not sticking anywhere, check the throttle cable to make sure it's not too tight and holding the throttle plate open. You haven't messed with the idle screw have you? You can check the IACV and clean it as well. Start with those things.

SoHov

I didn't change the idle, no. I actually haven't found the idle screw yet, I was looking for it.

Might help to get the full story too... I just got done swapping the motors. I left the intake, TB, Wiring harness all in the car to make it easier. The throttle cable didn't get unhooked.

I tried taking the intake off and felt the two vacuum holes inside the TB and they both have vacuum so I don't think it's a leak, seems like the IAC is stuck open or something. When I cover half the hole with my finger it idles down to where it's supposed to go. Wondering if maybe there's something wrong with something else... then the ECU is telling the IAC to be wide open, like the coolant is wrong or something.

I think too much.

--How can I clean the IACV? Isn't it like built into the Throttle Body?

snatch

You can remove the IACV and there is a screen in there to clean out. I think it's held on with 2 phillips head bolts. I'm sure there is a small write-up somewhere on here about how to do it. Search around a bit, I'm sure it's there.