starting off.

Stock bore 360, new rings, 280h comp cam springs to match, adjustable rockers, c6aer heads and streetmaster intake, 4100 carb (rebuilt by me)

Ive been fighting with this for about a week or more now.

It won't hold an idle of anything lower in the rpm (no tach havn't had time to hook up been fighting with keeping it running) But it will idle around 1200 or so and when i turned it down it keeps dying. So thinking it is most likely my carb rebuilding skills i pulled the edel, carb from my 351w. PUt it on fire it up and it started so i turned the idle down to where it sounds like it should be and it held fine. I then took it for about a 2-3 mile drive. About half way into the drive when i went to down shift for a stop sign the truck stalled when i pushed in the clutch, of course dad looks at me like i'm a retard and just learning to drive a stick lol. so i let it back out quick to refire and kept going. The next sign it did it again and the same with pulling in the driveway. So my problem is not fixed. That carb(edel) worked fine all last year so im 99.99% sure it has nothing to do with it. So after blocking the tire in the driveway i tried to start it. It wouldnt fire unless i pumped the peddle 1-2 times and then kept playing the throttle after it fired. As soon as i would let off it shut off. So i went out thinking maybe the idle screw moved or somthing, nope. I turned the screw IN and tried again, nothing. So right now the idle screw is in about 2-3 turns past where it idled at around 800rpm right before the drive and it still shuts off when i let off the throttle. The whole time it was stalling when dropping to idle it was still runing well while i was on the peddle. I'm not ruling out it being a carb problem with my 4100 i rebuilt but thats another post after i get it working with this known working carb.

So I'm thinking vacuum leak?? When i had the 4100 on it i had it at idle as best as it would and went around spraying with starting fluid on all of my vacuum caps and carb base. Nothing really increased the Rev's to more than what would have sounded like some overspray making its way into the carb. I also pulled the power break booster off of the manifold and plugged the hose.(i sprayed around the vacuum fitting for it and no leaks there either) I'm really running out of things to try. How prone are the intakes loosing seal on the heads and leaking there? I don't have a vacuum gauge but i'm thinking about buying one as i would like to learn carb tuning. Also after that short drive It didn't look like the secondaries were wet on the edel, Nor on the 4100 when i took it the day before. That might not have anything to do with the situation but i'm just trying to give as much info as i can think of.

I'm going to let the truck cool over night (work nights) and when i get home in the AM i want to see now if when i start it if the idle will be super high since the idle screw is turned way up. If it is i'm guessing it could be a vacuum leak that only really comes into play with its warm?

Any ideas i would be super happy of hearing. I'm running out of things to try with this. I have NEVER had this problem before with any engine. I do have a T-bird 4 barrel intake that i could put on if its an issue with the intake. Also as far as i know the heads have never been machined so ruling out them being shaved and the intake not matching, the intake I'm not sure if it had been shaved. Now with saying the heads have never been machined they did work fine on the 352 when i pulled them and cleaned them up and they have no valve problems that i can see.

 

Update. I just tried to start it. Went through the normal no choke start-up. Played the peddle for about a min keeping it running until it warmed up some and then it held an idle alone. It was high since i let everything just the way i let it after it wouldnt idle last night. I let it idle for around 3-5 mins checking for vacuum leaks again. I also noticed that there is nothing that i can feel coming from the valve cover breather, so i'm thinking my leak is under the cover and its sucking it all in and thats why theres no blow by. I honed it myself and its not bored so there has to be some since it wasn't a fresh bore, atleast i would think. I'll do a compression test cold and then after a hot drive tomorrow.

 

double post

 

try getting a baseline with your carb- turn both mixture screws in (gently!) till they seat, then back them out 1.5 turns. get the engine warmed up, and set our idle speed. As soon as you can get it to idle at all, recheck your timing! (Your description sounds like a timing problem to me). 10-14 deg advance should be ok, maybe even more if you live at high altitude. Once you've done this reset your idle mix by turning one screw in till the engine stumbles, then back it out .5 turn, then repeat with the other bank. reset your idle speed and you should be good to go.

 

Ok. I'll check that tomorrow and get back to you.

 

If you haven't bought a vacuum guage yet, Harbor Freight has a real nice one for about $10.00. YOU NEED A VACUUM GUAGE! And yes I'm shouting.

 

Ok. Checked the timing again. changed it a tiny amount. 1-2 deg. ran out of gas while setting it. So i went for 5gal and put it in got it started and took it for a drive. I drove the route i did the first time it acted up, and it was fine so i stopped back at the house and backed the idle down a little and went back out, Drove a little longer and came back home. Pulling into the driveway it did it again so i got the mail and talked to my neighbor and when i walked by the truck again i decided i would try it again. It only sat for around 5-10 min and it started and idled fine. I'm kinda lost now? I have no idea why 5 mins before that it wouldn't idle, It would shut off as soon as i let off the peddle just like i would have turned off the key, no coughing, missing or chugging. The total drive was around 10-15 miles for both trips.

As for the vacuum gauge at harbor freight i'll grab one the next time in in the area of the store.

 

I took it for a drive about an hour after i wrote the last reply. It was for around 3-4 miles after it had idled up to temp. It worked fine no problems. I'm going to put another 5-10 gal. of gas in it and drive it again later today.