xxxtreme22r

Ok guys, this has been bothering me for a while now, and since the weather is getting a little cooler around here, I thought I would get some clarification to make sure I don't actually have a problem. I will try and give as much info as possible.

Run down of my setup, 22r rebuilt motor, new pistons 20 over bore, block decked 10 thousandths, brand new stcok head from EB with a 268 cam, New valve lash adjusters, 170 psi in all cyls, Brand New Weber 32/36, EGR valve is still in place although disabled via disconnected vacuum lines and the pipe removed due to the weber install. Fuel pressure regulated to 4.5psi via a holley regulator, fuel return line blocked off per weber install instructions, 1 vacuum line going to the distributor on the port closest to the radiator and hooked to the vac port on the weber, all other vacuum lines either blocked off or looped to all emissions equipment and VSVs. Timing set at 0 degrees per FSM, NGK copper v-power plugs gaped to FSM spec, Valvoline 15/40 oil, PureOne oil filter. Manual trans.

When cold ie sitting all night and I first start the truck it starts fine with a few pumps of the gas. Typical for any carbed motor I know this as I have owned my fair share of them.

When it first starts idle is around maybe 1000-1200. Until the fan clutch warms up and releases the fan and then the idle will creep up to about 2000 RPM. Perfectly normal and understandable as the fan clutch causes a drag on the motor.

What I feel is not normal just unsure, I don't rememebr any of my other carbed trucks doing this. Is after that fan clutch releases to motor to idle at 2000 RPM and as the engine warms up still being on the high idle cam., the engine rpm will continue to creep up till hit hits my set limit of 2600-2700 RPM (yeah I know it's supposed to be 3000 rpm, but I don't want the thing to feel as if it's gonna fall apart. lol, yes I know it will handle it but still).

I do not remember if this did the same thing with the original AISIN carb or not, been a while. All I know for sure is it's done it at least since the rebuild.

So basically what I am asking is this a normal thing as the engine warms up, is it only with the weber or does others have the same thing going on with the AISIN as well. My thinking behind it is that it's running a tad rich when fully cold and until the choke opens up slightly when the coil warms up, then the idle comes up because the air/fuel mixture changes as the butterflies open up.

yotaman90

What size jets are you running and how many turns out is your mixture screw? Also, I think that fast idle is too high, even if it's close to factory fast idle speed. Mine is set to around 1500-1600 rpms

xxxtreme22r

factory jet, not sure which one, and the idle screw is a little further out (counter clockwaise) than I would like and could probably use to jump up one size. FOrgot to mention and is now added up top, is that I also have a downey header. and a brand new stock head with a 268 cam.

yotaman90

So you're running a .60 primary and a .50 secondary? I agree that you could go up one size, to a .65 and a .55. That's whats in my carb now

xxxtreme22r

would that jetting cause the idle to go up as the engine warms up, while the choke is on the high idle cam though?

yotaman90

I'm thinking no, but I feel what you said is correct about being rich when cold; the engine is a tad rich when fully cold and as the choke plates open the engine gets more air, thus idling higher. I would lower that fast idle speed though, but that's me

xxxtreme22r

Factory spec is like 3000 rpm, you think 2500 is high as well? Also like I said there is about a 1500 rpm difference between fully cold with the fan clutch still cold and the highest it will be while on the high idle. I doubt it will actually run any lower than 1,000 rpm when I first start it when fully cold, but I guess I can try.

yotaman90

I do think that 2500 rpms is too high, but that is solely my opinion; I don't like my engine spinning that fast when cold. Although, I think you what you are saying about the fan clutch is incorrect. The fan clutch on my truck is a NAPA part, not factory Toyota, and it seems to stay on for much longer than the factory Aisin unit on my 4runner, even when cold. My carb will slowly idle up when cold as well, but the difference is that my fan is still engaged. My engine starts out at about 1300 rpms and works it's way up to where I have it set at (1500-1600 rpms) over a period of about a minute depending on how cold is is outside. So I think your carb is behaving normally, unless somebody else can correct me

xxxtreme22r

yeah mine is an aftermarket one as well from autozone or advanced auto can't remember. not OEM I guess I should have mentioned that as well.