Here is exactly what happens..

After the car has been sitting, the initial startup process is perfect. Cranks, fires instantly, and runs smooth at 2500rpms (pretty normal for initial idle). Then, over the next minute or so, the rpms rise slowly but surely until they hit about 3000, and then itbegins surging from 3000 to 2500. I have not yet tried to let the car warm all the way up, and see if it goes away. That is another thing on the agenda for today.

Heres my checklist so far

Idle Set Screw - Adjusting that doesn't do anything to change the idle surge characterists

IACV - Checked, Cleaned (it was clogged pretty bad), and reattached. I have read that some Honda guys have illiminated theirs, and may give that a shot.

FITV - D Series motors don't have them, at least to my knowledge. I looked and there is nothing that resembles the unit under my TB. Someone correct me if I'm wrong.

Vac Leaks - I've sprayed carb cleaner just about everywhere, and have not found any leaks yet. When I kill the motor, there is a sucking sound, as if there IS a leak. But,if it was a bad vac leak, wouldn't the idle surge all the time, and not just after its warmed up?

TPS - This I have not yet checked, but will when I get home today.

IM Gasket - IM and gasket are properly attached and torqued to spec, in the correct order. I took the IM off last night just to make damn sure it was attached properly.

I'm kind of at a loss here. My tuner came over on Saturday to check things out, and even he is stumped.

Any and all info is greatly appreciated. Thanks guys.

 

My car does the same thing.I have yet to figure it out.I believe mine is the iacv you said some guys have bypass there's can you tell me how or give me a link please.If I start my car it doesn't idle till it warms up.Also once warm or coldaround 2,000 rpm if you hold the pedal stedy atit it will rev up and down on its own with the peddle stedy.I belive if I bypass or get a new iacv this should fix my problem.

 

I saw a couple people had just used flat gasket material, and put it inbetween the IACV and the IM. I haven't read too far into it yet though as I dont just want to start blocking **** off

 

I was reading about this also and I heard it drops your idle way low..My main prob is the surge at 2000 rpm's.Hopefully it will fix the no idle when cold or the surge when held steady at 2,000 rpm.

 

Heh, I was just talking about this with a friend the other day. He said that when people have idle problems with these cars, it' usually one of two things: (1) either the idle is set too high, or (2) coolant is too low. if the coolant is so low that it's not getting to the IACV (or it's getting air bubbles), it won't know the temperature of the engine, and it will idle weird.

Also, the idle screw tends to back out after a while, and from the factory it's covered in goo so that doesn't happen. ou might have to scrape it off to adjust it. But when people adjust the idle screw, they don't always put the goo back on.... so it may back out again eventually.

Also, what engine harness are you running? And what ECU are you using now? There's more than one kind of IACV (some 2-wire, some 3-wire). See if this helps at all. http://www.honda-tech.com/zerothread?id=558245

 

OBD2b engine harness, p28 ecu, OBD2B-OBD1 conversion.

Like I said the Idle set Screw seems fine, doesn't have any affect on the surging..

Coolant should be mint, but I'll double check to make sure. WIring wise I should be fine, but I'll check **** out anyway

 

so, D16Z6 manifold? how many wires on the IACV? you didn't have to re-pin the connector? chipped P28 or a stock D16Z6 map? did the engine come out of a running car?

and I don't know how to do it, but I think you can bleed the cooling system to get the air bubbles out.

I <3 questions. Even when I don't have a solution I like to understand the problem

 

me and Roto were just talking about this last night. He said some y8 IMs have 2 wire IACV and others have 3 wire. He said there was a chart that told which one was which, but he couldnt find it. Sorry Tony, but what block are you running now? I know its a D, but what one? Roto said that the idle would never be right if you were running a 2 wire IACV to an IM that needed a 3 wire and vise versa, so that could maybe be a problem?

And the low coolant seems to fit the situation perfectly, your car runs fine until the engine heats up ,and since theres no coolant reaching the IACV, the idle gets messed up,

btw i know your guys knowledge on Civs is way above mine, im just tryin to help

 

worrrd

yeah so it's a y8 IM on a z6 motor. So of course, I did not need to repin the connector, as it is the same IACV that has always been in the car.

Motor is in really good shape, and was pulled from a running car. Problem is, its been just sitting for over a year, needless to say it was a bit smokey the first time we fired it . Other than that, its strong.

Ecu is a chipped p28, burned with a stock z6 map.

 

any updates?