Idling problem

[ib042129]

So I think this is pretty much the last left over issue
with my H22 that's left. (Well I need a tempereature gauge but it's not
a problem yet.)

The engine is kind of weird during idling.
If the engine is cold, but running, the idle is fine.
When the engine warms up, and I shift into neutral,
instead of the RPM's dropping just to idle, the drop
VERY LOW first, then come back up.
This has actually caused me to stall on occasion.

ALSO! For some reason the car won't idle right after
getting more fuel in the tank. I have to hold the gas pedal
and drive for a minut or so for the idle to work again.

I'm really not sure what ic could be. Especially what exactly
changes after I put more fuel in the tank.

Guys. Please help.

 

[Donut Limo]

Bazaar. Is this modded or factory setup?

Wild guess but something to do with the EVAP system? system confuses me but i know there is a canister that holds vapors after refueling. maybe there is a solenoid that is stuck open allowing the vapors to be pulled into the intake at idle rather than higher rpm like its supposed to. you'd think this would cause a rich idle before the PCM switches to closed loop where fuel would be trimmed based on exhaust 02.

 

[Cameron_H]

Mine was kinda doing the same thing.

Mine would be fine when it was cold, but after I got where I needed to go, I would start it up and it would idle really rough, and I would give it a little gas, it would rev up hesitantly and then get LOW, and sometimes it would cut off.

But it quit doing it, I wish I knew what the problem was so I could tell you.

 

[ib042129]

Bazaar. Is this modded or factory setup?

Wild guess but something to do with the EVAP system? system confuses me but i know there is a canister that holds vapors after refueling. maybe there is a solenoid that is stuck open allowing the vapors to be pulled into the intake at idle rather than higher rpm like its supposed to. you'd think this would cause a rich idle before the PCM switches to closed loop where fuel would be trimmed based on exhaust 02.

My car has an obd1 h22 swapped in.
I think the evap may not be used.

 

[Donut Limo]

or maybe a simpler version of it.
that is weird, is it guaranteed to idle poorly after refueling or only sometimes? is it idling really low on all 4 or does it misfire too?

 

[ib042129]

or maybe a simpler version of it.
that is weird, is it guaranteed to idle poorly after refueling or only sometimes? is it idling really low on all 4 or does it misfire too?

Guaranteed not to idle after refueling. (For like a few minutes.)
No misfire.
Driving is fine, make good power.

It idles at normal 1k rpm. It just drops low for a sec when I go into neutral.

Edit: I was just talking to a buddy of mine.
So one possibility is this:
The 6th gen fuel system has three hoses: supply, return, vent (The vent goes to the IM.)
The h22 has only TWO! No vent.
I currently just connected teh vent to one of the vacuum oultets on the IM. (I don't have a bigger hole anywhere on the IM.)
Should I just cap of the hose insetead? Route it elsewhere?
Or does it not matter?

 

[Donut Limo]

jeez i'm not sure what to tell ya, this h22 stuff is uncharted territory for me. which pcm are you using? i think the vapor line you're talking about is the one going to the evap canister. the purge valve duty cycles to let vapor from the canister into the intake to be burned. i'd try to temporarily cap both ends next time you refuel as process of elimination. if it runs better it's only a bandaid- i think that canister plays an important role in the fuel system and you'd have to get rid of it or find a way to vent the fumes somehow.