Can't figure out why the damn thing wont idle, I have a feeling the distributor is on wrong because I hear some misses. It'll stay alive if I keep my foot on the gas but the MAP is readign 76 KPA at idle and the IAC is staying at 150. =/. Any suggestions? I checked for vacuum leaks, checked all the plugs and pushed the ditributor plug in to be sure its in.

 

And its not the valves.

 

are you sure the IAC motor is working? I think 150 counts is all the way out saying its trying like hell to add air. make sure the iac conn. has the power and ground to it and the conn.s arent messed up, and make sure the iac motor itself is working by swapin it for another one or try yours in someone elses poss..

 

IAC is functioning correctly, as is the TPS, all sensors are normal and no codes are being thrown other than stupid crap I always get (skip shift etc..., basically crap from the swap). I pulled the opti off to verify it was on correct and it is. Triple checked the wire order. Changed the spark plugs and gapped to .050. I can't figure it out, I got spark and I got gas. No vacuum leaks... Valves were good. If I don't get any good advice im gonna take the distributor back under warranty (just got a new one 3 months ago and only used it for 2 days!)

Any idea's here guys?

 

what program and what cam are you using?

 

Did it EVER run since you built the 383, or is this the initial startup with a new setup? Did you degree the cam? Did you check the timing gear install to insure the dots were in the correct orientation?

 

New buildup. Timing chain lined up dot to dot on several turns. Verified this quite a bit to be assured it wasn't one tooth off. Never degreed the cam, don't see a reason to as the last two times it installed fine considering it has 4* ground in. Any reason the MAP would be reading 76KPA during idle with my foot partway on the throttle?

 

When you open the throttle, the intake manifold is exposed to the higher barometric pressure outside the engine. The only thing that causes MAP to be lower than "Barometer" is the degree of closure on the throttle blades.

 

Weird, when I get home im gonna double check those valves.

 

actually, I have one exactly like this at work (ofcourse its not a perf. ar or anything,) but its exactly what you decribed. wont start w/o opening the throttle a bit, and runs perfect except wont idle on its own till it gets a little warm. in my case, all the sensors are reading good and everything seems right except the IAC counts are high around 170 when its at its worst, and it got better as the day went on to around 75. if I figure out exactly what my problem is I'll let ya know. Im thinkin bad gas cause it was really low, and we filled it and its MUCH better. how long has the gas been sittin in your car? it could have some condensation in it. also, I removed the IAC valve to clean it and the egr valve to make sure it wasnt stuck open some. not sure it that helped or if its just a coincidence that it started better as the day went on. did you block off the egr valve on your eng.? if not start there.

 

you may be onto something with the gas. Gas has been in the car since january. EGR is blocked off.

 

I have always store mine with a full tank for 6 months or more and never had a problem. Was your tank full?
I just finished my LE2 383 head/cam and she fired immediately on 8 month old gas. Course, it is so loud I doubt I would hear the end of the world coming........ but it idles fine.

 

About half a tank. Yea i also fired a engine up about a month or two ago no problem. When I head home im gonna pop the valve covers and see if I got a bent pushrod. Would my symptoms be the valves are too tight or too loose?

 

I had my valves pretty tight, and after adjusting them (with the engine running) it helped a lot. If they are too tight, you will not get good vaccuum, and misfires. How much throttle do you have to give it to idle good, or what RPM will it die at? You may just need more air than the IAC can give it. Try adjusting the throttle plate screw so the blades are open just a touch more. What year is your car? I had my opti vent tubes hooked up wrong, and for some wierd reason, it caused the car to die when warmed anywhere below 1500 RPM. Yours is probably not that, but its just an idea.

 

Is the idle high or low or surging?

If the IAC counts are too high then the motor is basically choking until you crack the TB blades a little or open up that TB bypass hole(on the stock TBs).

The best way to really set the valves in my opinion is with the motor running so you can feel and HEAR zero lash so as to minimize the chance you set them too tight.