D15B Dual Carb rev fault - revs itself to 3.5k-4.5k rpm!!! Please help...

[Mariozas]

Hi all, so this is how it happened - got in to my car (its 1992 EG4 JDM hatch with D15B dual carb) , started to drive and just after few km's of the road I felt something's wrong when tried to shift in gears - while used clutch revs raised from ~3k rpm to 4k rpm then I thought what da f@k, and pulled over, shut off the engine, opened the bonnet and didnt noticed any weird s**t, so started the engine again, it was grand maybe for 30 sec's and then it all began again - idle is reving up to 3.5k-4.5k rpm.
Suspected alternator but its just fine, checked all vacum pipes all seemed to be ok ... ecu doesnt show any error code, and when tried to drop the trotle down by hand on carbs - it feels that engine doesnt burn gas properly - feels klike some cilynder would missfire sometimes and u can see alot smoke from exhaust. engine sounds ok when working on high rpm - no smoke no knocking, just high rpm...nightmare for last two days to drive it!

Please help ...

damn dual carb sucks...

 

[PhntmSk8r]

Throttle plate is sticking open.

 

[Mariozas]

what do u mean by that? probably all I need is just spray carb cleaner to throttle plate all around and it should sort all out?

any suggestions? where should I begin?

 

[Mariozas]

Fault Solved ->>> Please Look!!!

So finally I have found the dam vacum valve of some sort on the left side of the left carburetor that is going crazy on most times now lifting the carb / mixture idle plate of some sort so mixture gets very rich and idles at very high then - everything solved after disconnecting that single hose from that thing, but it doesnt accelerate any more as good as before when over 5k rpm but still drives like a hell! Anyway here is the location of dam s**t thing - hose from it goes direct to black magic electronic vacum control box where I should say - all vacums come from

 

[raysteve]

Whew..I guess this is a complicated situation you are into with your carburetor and some other engine parts. Just wondering if you were able to resolve it already?thanks

 

[Mariozas]

yeah I got it sorted, it was something to do with right side carb idle setup, it was out of settings with the idle screw, loosened it to the loosest and high rev jumped down to normal. some dirty fool messed all around