ok so, takes a while to start (10 seconds is the longest, ususally 7) cranking... and once it does start, it idles at 2k (or so my tach says) but i can feel the car pulling faster when i let off the brake, so its definately idling high..

i used up about 4 cans of carb cleaner looking for vac leaks, i didnt find any in the hoses but i did find out that the TBI gasket needed replacing because when i sprayed a spot the car would bog, so it was definately sucking air.. so i did that but there was no change in the idle... so wtf... anyways, when i start it up, (without the air cleaner on currently btw and the air cleaner to TBI hose is plugged, i can hear a super loud hissing noise. is this normal? i think it goes away after a little while or maybe i just get used to it... and also, one time i sat there idling waiting for it and i was able to get the rpms to get down to 1k.. but it took me about 7 minutes. shouldnt take that long should it? and it shouldnt be hard to start either right?

i have a new fuel filter and plugs and wires/dizzy and rotor... and a new battery, and timing is at 0*

what do u guys think? IM me on AIM, my SN is "iiawk" i really need to figure this out, trying to get car in top condition to pass CA emissions and inspection. thanks all!!!

 

Tried cleaning the IAC .. and making sure the connectors to it are in proper working condition ?

 

got a brand spankin new IAC (after i cleaned mine out thoroughly and tightened it too much and broke it in half...somehow, i swear i didnt do it THAT hard!) anyways, thats in now, car still idles high... i also replaced the hose to the PCV valve suspecting vac leaks AND replaced the PCV valve... when i start the car there is a SUper loud hissing noise... is that a normal noise or vac leak sounding? cause i cannot find vac leaks for the life of me...

anyone know where those two plastic hard vac lines go to, the ones that go down into the wire loom right behind the auto tranny fluid dip stick? on the passenger side... they are really the only ones i havent changed out yet, (cause i dont know where they go) all of the other hoses i have pretty much swapped out for new line... im using the stock hose for the canaster, map sensor, and those two plastic hard lines...

there is also a weird vac hose situation behind the distributor... right infront of the dizzy there is a metal nipple thing that comes out of the intake manifold.. it had a vac line attached to it that split into a T.. one of the routes goes into the loom (the second vac line) and the other end of the T runs to the cruise control i believe... does that sound right? ill post up pics... it almost looks like there is a check valve for the T... bah i need apicture

 

The super loud hissing/whistling noise is very likely a vac leak, and the cause of the fast idle. Take some heater hose, put it to your ear, and use the free end to try and isolate the area that has teh leak.

 

ok i took a flexible tube and used it like a stethoscope and found that the hissing is just coming from the intake, when the aircleaner is off, its coming from the opening in the TBI.. it gets quieter after time, seemingly directly related to the high idle...

when the car starts cold it hisses really loud and idles really high... then when the idle drops, so does the loudness of the hiss... any idea what causes this?

i dont think its a vac leak anymore but i dont think its normal that it should be that loud/idle high at first/and start hard...

 

Mine idles at 1500+ rpm for the first 2-3 minutes .. I always let the engine warm up nice.. after that it drops down to maybe 650-700 in neutral or park

 

ok also, i set my timing to 0*, whats the best t set it at for my stock 305? i have a less restrictive muffler and open element air cleaner if that makes any diference... i set it to 0 for trouble shooting purpose, and now that it seems that my car is behaving more normal with its idle, maybe i should increase the tming to help the hard start problem?

 

4 .. maybe advance is to 6 .. *shrugs* different for different people

 

ok i set timing to 6* (looked in the haynes manual and thats what it said) didnt do much but make the car start a little faster and run a little smoother... then i checked the vac lines, because there are still some issues

1. surging idle (slowly drops in rpm till it gets pretty low and then shoots back up and starts to slowly drop again)
2. stillhard to start, i put some more gas in it too just to make sure it wasnt that it was low...

i checked again for vac leaks, and this time i checked for suction of the lines...

on the TBI, the hose that goes to PCV, the hose for the Aircleaner, and the hose that runs to the weird little electrical connector (egr solenoid?) all had suction, the hoses that did not were the canister hose (which i think is normal) and the hose that comes out of the electrical egr solenoid To the EGR itself, that line was dead, is it supposed to be?

the MAP line had suction, pinching it at the MAP connector causes the car to die immediately...

i think i have figured out what the hoses are that go into the wireloom and possibly into the cab...

one goes directly to the black UFO thing for the heater tubes, and it goes straight down the wireloom, i think its the HVAC controls...

the other one is the left part of the T that comes out of the intake manifold nipple... the right branch of the T goes to the cruise control...

does that last part sound right? intake manifold nipple to a T (with a weird checkvalve possibly as the T fitting) that goes left and right, left down the passenger wireloom where the HVAC goes and right goes to the cruise control...

ok phew, what do you guys think? is the EGR supposed to have suction? if not? where should i look for vac leaks? i have used 4 cans of carb cleaner looking for leaks... i think i might replace the MAP and EGR hoses (3 hoses total) with regular vac line at kragen just to eliminate the possibility of a leak with those hard plastic lines...

ill get a picture of the weird T intersection with the cruise control and the check valve thing

 

Check around the base of the intake manifold ... for vacuum leaks ,,, front and back china walls

 

I dont know if this with help but...

When I start my car cold (after it has been sitting) not matter what the outside temps are I get a loud hissing/sucking noise EXACTLY like what you have described.

I ALSO checked for vaccuum leaks due to a surging idle problem I am having.

"Just like you, the hissing dies down after the car has been running a while and has properly "warmed up".

I was told that the high surging idle is due to an aftermarket cam with a lot of valve overlap sending alternating rich/lean signals to the computer, which doesn't explain the noise.

But, I was also told that open elements can cause a loud hissing noise on TBI vehicles, which does somewhat make sense due to the fact that the hissing/houling noise is deffinately coming from the throttle body openings.

 

what you just said confirmed what im hearing... i have looked and yes the noise comes from the opening of the TBI, for some reason my surging seems to have diminished, i am going to start the car cold in a minute now and see if it surges again, the past two times i started it, it seemed to run rather smoothly. it still has a hard start problem though. I will update tonight.

 

Any solution?? My L03 truck does the same thing and its got all new vac lines, all new sensors, rebuilt dist. , its got the works...

 

Sounds like the IAC just "telling" the TBI to suck it in, pump it in, let's heat up that engine

 

In my case the surging idle was partially due to a worn throttle shaft. I swapped the TB for a rebuilt one, adjusted the blades so they don't completely close, and took a fairly large amount of timing out and it idles much better than before. (Note: I have a different cam)

I would double check that there is no play in your throttle shaft and it is still in good, working order.

Next guess would be the ECM.

I still have the hissing, but I am sure it is the motor pulling a lot of air to warm-up through the open element (not the quietest)