90_Si

Ok this one is driving me nuts, I have tried everything, the IACV has been cleaned, and it has a new distributor and plugs.
Problem: When I first start the car it will idle solid at about 2 grand, after any gas has been given it will idle with it constantly bouncing between 900 and 1500 rpm. When driving it seems to drive fine, other than the high idle when the clutch is put in but when coming to a stop it will either stall really bad or it will die. It then starts up and the process repeats.
I unplugged the iacv and it stopped the bouncing idle. I also unplugged the tps and it stopped the bouncing idle, but it still died when stopping. One thing I have noticed is that if it is just started and just idling high and i start pumping the brake the idle will rise about 500 rpm the whole time im doing that but then drops back when i stop. If I do the same thing while its doing the bounce idle the ultimate idle will be about 500 rpm higher (up to 2500 rpm vs 2000) and then when i stop pumping it will go back down to have a 2000 rpm maximum. The brakes work fine and when i undo the vacuum hose from the booster it will idle at 3000 rpm for a few moments then start a bouncing idle like one would expect.The engine is a SOHC ZC with an intake manifold from a 90 Si. Any help would be extremely appreciated.

The_Undertaker

Make sure all vacuum lines go to their respectful place. Make sure their is no air bubbles in the radiator. Bleed the system. Make sure dizzy is the center. Not to advanced or retared. Make sure the timing is set at TDC. Make sure TPS is connected. Any codes.

90_Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1988hondacrxsiR1 &raquo;</TD></TR><TR><TD CLASS="quote">Make sure all vacuum lines go to their respectful place. Make sure their is no air bubbles in the radiator. Bleed the system. Make sure dizzy is the center. Not to advanced or retared. Make sure the timing is set at TDC. Make sure TPS is connected. Any codes. </TD></TR></TABLE>

The vacuum lines are in the correct place, I am going to double check them though. This has come up fairly recently, it was driving for a few weeks without this happening and no vacuum hoses have been taken off. The coolant system has been bled and i double checked it today. The dizzy is brand new and is in the center. The valves were adjusted at the dealer about 2 weeks ago where it also got a new fuel pressure regulator and o2 sensor and the tps is connected, when i unplug the tps the bouncing goes away but it still dies at a stop. The bouncing also goes away with the iacv unplugged but i cant drive it with that unplugged because of the severe bucking that would ensue.

The_Undertaker

Any codes?

Jonathan_ED3

This problem went from being a fuel-seeming issue to a spark issue (no spark at one point!) and now we can't figure it out. It's a ghost!

In the process of tracing down the phantom problems he's repaced:

Main relay, FPR, fuel pump, injector o-rings, distributor and it's internals along with cap/rotor are brand new. timing has been adjusted as well as the valves.

It's got to be a sensor or a vacuum leak. All the hoses are connected and if there's a vacuum leak we cannot find it.

slow_rex_will

Have you checked your ignitor inside the distributor? Just one of many possibilities!

90_Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slow_rex_will &raquo;</TD></TR><TR><TD CLASS="quote">Have you checked your ignitor inside the distributor? Just one of many possibilities!</TD></TR></TABLE>
There are no codes unfortunately. It has a brand new distributor, the old dizzy kept on burning ignition coils out so now it sparks like a champ. I just cant see how it could possibly be a fuel or spark issue. It has a brand new fuel pump, filter, main relay, injector o rings and fuel pressure regulator. The distributor, wires and plugs are brand new also. The map and ecu have also been tested and are good. I am at a total loss as to what the problem is now and its really frustrating because I kind of need the car to drive haha. I need to find a good IACV to test with before i spend the money on a new one. I really dont know what it could be other than an IACV or the TPS, I dont think I have a FITV.. if i do please correct me.

89D15CRXDX

Did you ever figure this out? I'm having the same problem with my JDM D15B motor and it's beating me up. I have the bucking when not giving much gas in any lower gear (1-3).

Jonathan_ED3

No we still haven't figured it out.

The kicker is that the car ran fine for about a month before all these problems popped up!

Eghatch93

bump

my cars doing the same thing but it doesn't die out.... just idles up and down like crazy at about the same RPM's. Cleaned up the IACV, no loose lines

mjfx

same problems for me too and i have been driving my car for 1 year and this is the first time it does this. in my case the RPM do not bounce it just shuts off when i'm not in gear and not giving it gas. and if i take it out of gear at low RPM the car will stay one but only at 200 RPM. could the idle need to be adjusted?

1kleenef

same problem on a jdm dohc zc motor plz someone help

Jonathan_ED3

Now this car won't start. No CEL's.

EF2_Sedan88

I may sound stupid how about try the alternator

mjfx

i think i have spotted my problem. one of my air sensors on the throttle body broke so i am going to the junkyard on wednesday to get one. i'll let you know what happens.

bossman032

my 89 si all of a sudden start doing this for the last 3 days. I was really pissed off. I took off the idle valve and spray some carb cleaner and nothing. same problem then I took the brake booster hose off then sprayed some carb cleaner in the engine. still same problem then took off the battery and let it sit for a while then started and then bam problem went away. my car never had any idle problems.. just happend all of a sudden, hopefully it has went away..I will update after a week or something. I thought it might be a vaccum leak or some senssor ******* up but I don't know it went away lol..

Jonathan_ED3

his car still won't start. Blows big time!

bossman032

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jonathan_ED3 &raquo;</TD></TR><TR><TD CLASS="quote">his car still won't start. Blows big time!</TD></TR></TABLE>

LOL! no spark?

kwizical

was it your fuel pump?

jamison1486

ive gone through two iacv's in the four years of owning my b16 crx. in my area it seems common for the iacv to go, and with me and a few others i know that have had theirs go out, they've always gone out in the winter??? its an easy fix but pretty expenseive. if you can, borrow one from a buddy and see if it makes a difference. good luck.

dubstackz

to get the idle to stop bouncing all u have to do is adjust the screw on the front of yer throttle body in or out till it levels off

PuroMotor

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EF2_Sedan88 &raquo;</TD></TR><TR><TD CLASS="quote">I may sound stupid how about try the alternator </TD></TR></TABLE>


not stupid at all... had the same problem with a d16 and it ended up being just that... a weak alternator...

tunerkid7

OP- What ever happened??

Along with the guy that was gonna go to the junk yard for the air sensor??

Want to know if its just the iacv??

kwizical

i was having the same problem ended up being a bad ground on the fuel pump. changed out the ground works like a champ.

Jonathan_ED3

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bossman032 &raquo;</TD></TR><TR><TD CLASS="quote">

LOL! no spark? </TD></TR></TABLE>

The car keeps blowing out ignition coils.

Even before the coil shorts out or fries (whatever it is doing) the car doesn't idle right.

We haven't touched the thing in weeks. We're going to start looking at it again today.