Hey All,

 

Just finishing up a 302 project for my truck and need a little help.  Engine is in, runs, and drives, but not great.  Has a bit of a stutter when put into gear other than park, can't seem to get idle tuned in properly with set screws and have a exhaust leak thats driving me insane..

I know this isnt much info but here goes, engine is out of a 79' T-Bird with FMX 3spd behind it.  Holley 600 on top (non-egr). I have gone back to out of box settings for the set screws for idle mix etc and tuned up and down and cant get this thing to idle right at all, not even when its at running temperature.  I believe this is being caused by a leak coming from the back of my heads.  I guess there was a thermactor tube thats was there with the egr and ir pump etc.. Well theres nothing there now haha. Is it odd that Im only getting a leak from one of the 4 holes in the head though? and will this be enough to not allow the carb to be tuned proper or idle proper?  Either way, the engine is in and its gunna be a PITA to get a bolt into that hole in the back of the head to plug it as it is near jammed up right against the fire wall.. I believe there 5/8"-11 corse thread, some ppl have said use a spark plug but theres no way that it fits, spark plug is far too big.  In any case my plan is right now to try and plug all holes in the heads before attempting to tune again.  I was just wondering if anyone had any tips for me or if anyone in the area could come take a look see next time I fire this thing up. Im kindsa new to the whole carbueration thing and am at the point of pulling hair.

 

On anothre note I have no thermactor tube or air pump hooked up and seeing as though its a OBD1 vehicle I still need an etest under hot rod designation this spring or ASAP.  Is there ANY chance of this thing passing without that? I have a decent cat setup, charcoal can, pcv, and fuel return etc.. just missing the integral egr valve.  I have run a honda without a egr and it has passed somehow a few years ago, and I know the hot rod class involves standards for a 1980's engine.  This drivetrain is brand frickin new with almost no miles on it. Im really praying for a pass but Im skeptical.. Any help would be greatly appreciated.

 

Thanks! CK.   

Ok so i failed to mention that I did get out the vacuum gauge in the fall before I put er in the garage for storage. If my memory is correct the reading at steady idle (park) was about 16-18? Maybe slightly low and when accelerating it dropped to almost 0 and came back up to 23 before leveling back out around 16-18. Now i belive my problem was when truck was in Drive. The vacuum reading has slight flucctuations which were in sync with the rough idle. That to me says bad idle mix or vac leak, but with the readings in park being somewhat normal i figure maybe its not a vacuum problem.. It should also be said that when starting the truck idle is very high choke on or off doesnt matter, comes down to somewhere normal at running temp but ive played around with different return springs and idle adjustments and still cant seem to find the sweet spot.

@ slim - Well I still have all the old computer installed in the truck, wasnt really sure what I needed and what I didnt need (not too bright on electrical, im a chemical engineer haha) just had a friend help me out and do away with some things that I was told I didnt need. Im pretty suer the ECM is still hooked up in some way or another. The smog test for the 2 speed idle Ive heard is easier to pass now than before, just put a sniffer in the exhaust and run at idle and 2500rpm and see the readings. I've yet to take it to a place and try due to it not running correctly. I have duals (not true) but have a cat system in place. As well as vapour line from fuel and char can, pvc and good air cleaner. Just missing the thermactor tube, air pump and egr etc. Im thinking I can probably get away with the air pump but add the egr and at least make it look good. These two things are separate equipment correct? I think if I add the egr and spacer plate it wont work with my holley I have on top right now for two reasons, not correct holes in carb or edelbrock rpm intake compared to the spacer plate and no egr vac on holley model 4160. I have an old 4bbl carb and intake from a 302 I could try, not sure how long its been sitting, but definitely original and thats where all the egr stuff came from. Would still have to hook up new throttle cable etc but maybe worth a try..

In any case I guess my next plan of action would be to plug the holes or add a themactor pipe, get it tuned the way it is and maybe look into the random obd1 mess i still have hooked up, and if all fails try another carb setup..

Thoughts?

-- Edited by CraigK on Thursday 21st of February 2013 01:10:13 PM

1979 302 was it originally carbed or tbi?from what I understand the distributor for the tbi wont work worth a crap

wiring for the carbed version . if this is what you have then go after the leaks

Thanks for the tips guys, definitely will be checking these issues out in the next week or so when weather gets a little warmer. My dist. only has two wires coming off of it with no vac advance, I failed to mention again that Im running an msd ign box with my setup. Pretty sure timing is close but Ill be sure to get the light out and check again. Float levels could also be a problem, I've tried setting them by running fuel pump on/off for a few seconds and trying to fill them up to sight screw before it bleeds out (I think this is correct way to check level on the holley) but after about 20 times of engaging pump still no fuel showing at the sight level. I am running the oem in tank fuel pump with pressure regulator at about 5psi (no room for mechanical FP due to steering shaft) so maybe Ive just been impatient and need to send more fuel forward before I see anything leaking out. I've also messed around with the psi settings, doenst seem to be much change in engine idle from 4-8psi on the regulator.

Either way Ill keep trying and worst case maybe I can enlist someones help from here to come have a look or take it to a garage to fix all the last little problems, how I hate paying for auto repairs!

@pint n pound - Great idea for getting a lil clearence at the firewall for the thermactor plug! I might have to pull the WP pulley, theres only about 1" clearence from pulley to rad in the front of the bay, and thats with excessive fab work to tuck the rad under the core support haha.

Dizzy is a pro comp 8000 series with no vacuum advance. Probably the wrong choice for the setup but it seemed to work for the time being. Maybe this is part of the problem, i might have to turn out a bit more cash for a msd one with vac advance so at least that will eliminate one port in the carb and maybe help the idle problem.

-- Edited by CraigK on Saturday 23rd of February 2013 11:47:18 AM