cant reach base idle

[CRXer]

ok..heres the situ,

jdm b(loody)18c(rap) P72

can get it down to 500rpm

but

idle screw all the way in,

blocked the evap outlet-still the same

blocked the fpr & iab outlet-still the same

fingered fitv-very slight suck but no change in idle

fingered iacv inlet-more pronounced suck but no change in idle

cant get to pcv yet,manifold still too hot

1. is it normal for the fitv & iacv to suck slightly,even though didnt change idle?

2. am i being too pedantic & 500 is close enough to 480 +- 50rpm?

3. is it normal in some situations to have to screw the idle set all the way in to achieve this?

help! its nearly midnight i gotta get some sleep tonight

[CRXer]

oh one more thing

yes i did block the brake booster outlet,still the same.

edit:just saw a thread regardin MAP o-ring,didnt think of that,will check it now,but did check the iat seal.

[Slow96GSR]

So you have the set screw all the way in on the throttle body? Pull it out a little bit if you do. Also try adjusting via Distributor or if you have adjustable cam gears you can adjust a little there.

Here's a DIY I did a while back http://www.ozhonda.com/forum/showthread.php?t=50667 and if it doesn't load here is the same one on my site http://www.strathlan.com/CMS/viewtopic.php?t=34

[CRXer]

yes set screw all the way in.

stock cam setup

so a little bit of timing adjustment will drop my idle?

should i disable the ecu compensations before i try to set base idle?

[CRXer]

You do realize that 480 +- 50 means that it could be as low as 430 and as high as 530 and be within specs.


yeah,but with the idle set wound right in?

doesnt seem right to me

im guessing u should be able to virtually stall the thing with it screwed right in

it looked like it had a factory paint coatin on the set screw & i had to break this & turn it about 5 full turns before it stopped & wouldnt go any further & it just barely reached 500rpm.so if it was factory set u wouldnt think the right figure would be far from this point let alone 5 or more turns away.

so theres gotta be an air leak somewhere,gaskets are the only things left to check,couldnt get the pcv hose off the manifold to check,its damn hard to get too on the p72 manifold & ran outta patience,but did get the pcv out & blocked the hose-no change.

fairly sure now the set screw shares the same inlet as the iacv,i cant see into my throt body to see if another hole in there,can barely get my hands in there let alone my head,but if u wound the set screw out the iacv hole sucked harder

tried fiddlin the timing & things just got worse,now i can just get 600 rpm.

so to reset my timing again i just turned the set screw up to 750 rpm with iacv still unhooked & reset it to 16 btdc,cos the iacv just takes it straight to 1000rpm now & not below no matter what i try

could this be a 1 tooth out scenario or somethin? the motor has never felt quite right......the belt was changed during transplant

[Slow96GSR]

Anythig can be off right now. I would double check it. Yes changing your ignition timing can drop the rpm's, it can also raise it. You need to make sure there are no vac leaks. This will cause the motor to surge, got up and down on rpm's.

[JasonGilholme]

Might be stupid but have you check the tension on your throttle cable?? throttle butterfly might be open 0.1% which will give the engine a few RPM raise.

Also, Take the car for a bit of a drive before setting idle. i find that when i let my car warm up in the driveway the rpms drop while it warms up but once i take it for a drive (10 minutes or so) it drops even further.

Might help out.

Goodluck.

[CRXer]

Thanx jase,but yeah the cable does have a little slack in it & i had to wait for the fans to stop on numerous occasions while tryin to set things, even reading all the temps etc of a datalog so no ign compensations goin on cos it is up to temperature.

was gonna start playin with the throttle stop screw,but another bitch thing to get at on the p72 manifold & also thought im gettin ridiculous now,noone wouldve played with it before,could still even see the factory paint mark on it.

[JasonGilholme]

Yeah it does sound pretty ridiculous.

Hope it goes well. post up the answer when you figure it all ou.

good luck.

[bennjamin]

is it possible there is a slight conflict/inaccuracy between the b18c sensors and the CRX dash ? (made for a D16a8)

Ive noticed , with my b series in my EG5 the tacho is slightly off (IE VTEC kicks in at "apparently" 5,800 rpm)

[CRXer]

thanx ben,i got the DC2 cluster installed as well so should be as accurate as a cluster gets.

but im reading all the figures off a datalog anyway,so all figures quoted above are spat straight outta the ecu.

cheers to slow & clay for their input as well

ive given up on this one for now,stumbled my way back to a better idle & timing & got the thing retuned anyway today,was gettin a fair bit of knock so had to get it looked at.was just tryin to do a bit of quick maintenance on monday evening before the tune & it all went to shit.

lesson learnt: never pull car apart on a weeknight,theres always something else lurkin underneath the original task.

i'll attempt this again when got more time,but would appreciate any further input if anybody got any:thumbsup: