any common things related to hunting...

[Colza]

Beaten with a large stick?

[James]

The "fat idle valve"  ;) works by sucking in air from one of those two holes in the red plenumy thing on top of the engine, feeding it around the throttle body and then into the manifold, effictively a controlled vacuum leak. Try squeezing (blocking off) both of the hoses coming off the plenum while your engine is hunting and see if it stops, do it when its warmish or else it will prolly just die  :D This is also similar to what the auto choke does, but that cant oscillate nearly that fast. Also have you guys tried cranking up your idle? That is one reason I have seen them hunt, because the idle is too low so it drops so the computer opens the fast idle valve to raise it so it goes to high so it turns it off so its too low, etc etc

Keep us posted  :)

PS ha broke the big 3 digits barrier

[Smithy]

my idle screw is turned all the way in for low revs, although it never goes lower (maybe once in a blue moon) than say 1050.    Although when it hunts
it drops to 600 odd then up to the 1200 ish mark
then after while holds at 1100 ish again.

Oh, the hunting is bouncing away whilst its warming up too, on cold or hot start.

I might try playing with the hoses going from top red
plenum thing see where they go and bypass the solenoid fast idle mess.  see what happens....  

maybe just block em off...?!  (wont effect or damage mixture/lean-ness/pollution whatever!?!?)

[Colza]

I can drop the revs on my car down till almost stalling without the hunting starting. I think raising the idle above the 'hunt-threshold' will be one of those treating the symptoms but  not fixing the problem things...

[Kam]

I gave up on my rev hunting problem.  But one day I decided to change the ignition lead that runs from the coil to the dizzy cap from an 8 to 10mm and guess what?  IT DOSN'T HUNT ANYMORE .  Don't ask me why but it worked so give it a go!

[AnimaLector]

fella before me just bought new leads for it so I don't think that's it. I will try upgrading the size as a last resort though so thanks for the suggestion  I'm getting ym Cam tomorow.. yay.. we'll see ho0w it goes after that.

[Smithy]

Hmmm, I actually tried the replacing the lead once, with a 10mm splitfire or topgun or some thing.....

...except its was damage and worn which probably why removed from other car....I didnt realise till I made sure it was a good fit and the jolts from the dist.cap made me just about throw my arm through tthe bonnet...
...my brother thought I'd had my hand ripped off in the cam belt or the fan or something.

....But I thhink i'll buy a new 10mm lead and try it out any way, bigge can;t hurt performance or reliability hey
so its only a few bucks , so worth a try....
:)   next week though I think...

[Smithy]

Ok , had a drive, engine warm (water temp still not going above 1-5th to a quarter), any way,
fan was kicking on anf off and the hunting poppin gon when fan was as usual....
...OK So I pull off both hoses coming off the PGM-fi bit
and block off the two bit comin goff PGM plenum thing, and block the two hoses also...
hunting stops, when fan on now!!!
release blockages when fan on hunts...block again , it stops.!!  YAY have to try with a  cold start and see effects... but it was still idling about 1050-1100...
anyway better then bouncy revs...

so I might block them and bypass those solenoids for a bit see how its goes...  :)
-------
UPDATE---Ok , the too hose bits off from PGM f1 bit I connected together with a short bit o hose.
the two hose that woulv've been joinmed to PGM F1 I blocked off each...
now first it seemed better...BUT.
it soon began hunting...thing is under load , IE FAN,
it doesnt adjust up now, it drops but doesnt hunt whilst doing it.   But it seems to idle hunt otherwise as usual, just not when under load now   >:(

Im in process of updating my control box hose list and working out exactly where they go, as it helps me understand it more.
Maybe I should try blockin goff the return hoses too...
maybe that has influence, pretty sure they join back to inlet manifold AFTER the throttle body, (may be its a evening out of pressure system, I dont know....
I'll soon post my diagrams and explain...

[Smithy]

OK I'm 99.9 % sure these are correct...

I need diagrams like this when explaining or tryin gto understnad what some of you are on about  
LOL

any way:


[img]
http://www.cityturbo.com/gallery/albums/album48/Control_Box_sortinghunting02.jpg[/img]

[Colza]

[quote author=crooky link=board=GEN;num=1092816647;start=15#15 date=08/23/04 at 16:06:26]I actually think that the hunting on some of the Citys has something to do with the water temperature.  When i replaced my thermostat i noticed that the car runs just slightly cooler than it did.  When I flog my car a bit or before the thermostat opens fully, my car idles perfectly.  As soon as the fan or radiator does its job and the water temp drops just a little, the revs go up slightly, enough to reach 1200 rpm and start the hunting dilemma.[/quote]

Ive just had a thought (gasp ) When i get my engine out, i will take the thermostat and do the 'put in pot of water' test and find out what temp it is opening at. If we know what temp the original city turbo one opens at, we could set about getting one that opens at the right temp, instead of the one that everyone is getting sold which appears to be too low.

If you dont want to wait for me to get off my lazy ass does anyone have a car that HASNT been hunting that they dont mind taking the thermostat out of briefly? Makes a bit of a mess but its for a good cause

[Smithy]

Hmmm...yeah for some reason water temp has always bugged me with the hunting too.

Is there anyway to alter a thermostat to be set for a higher temp....I now youcan drill a few holes in for a lower temp but what about the other way around!??!

[Colza]

Not really. But thermostat manufacturers make MANY different thermostats. The ones in cities are more or less (maybe even exactly) the same shape as the ones from old cities, civics, accords, tons of stuff. With any luck one of those, or perhaps another car entirely may have the right shape at the right temperature seeing if it IS actually different from the standard city one that everyone is getting sold would be a good start i think!

[James]

to the best of my knowledge youll need to be looking for a higher performance engine than a city turbo to score the thermo, as thats why they run engines a bit hotter, for better performance. Not hugely likely to find one in the older honda range i would imagine but maybe something like a vtec engine might have a hotter one.

[mozzy]

[quote author=Colza link=board=GEN;num=1092816647;start=60#69 date=10/25/04 at 14:27:15]If we know what temp the original city turbo one opens at[/quote]

97 degrees Celcius (207 Fahrenheit).

[JohnT]

You have checked the bleed for air bubbles on the thermostat housing? See my item in the info base.

Hunt is air bleed, over rich fuel supply or air bubbles in thermostat housing on large proportion of occasions.

John T