For those with short term memroy loss, its a 66 429... pertronix ignition... No pictures until its "Finished," been putting many hours in on the thing. Looking better, at least. Following description applies on 85deg plus days... OK, after ya start it up from cold, it runs great. Fine. No trouble for many many miles. Then, if ya Park it for a few minutes and then try and start it again, it all goes to shit. Too rich, hard to get running. runs like crap. BUT, once some air gets moving into the engine compartment, its starts running better, almost perfectly. I caught a good whiff of the exhaust, definately rich. Running in traffic sometimes brings it about too. Here's whats been replaced, fuel system wise.. new and well sealed intake manifold gaskets Known good 650 cfm edelbrock AFB carb (according to Creeper Larry!) LARGE new air cleaner/filter Teflon spacer under the carb instead of phenolic stocker... All new rubber fuel line throught system New gas Fuel pressure seems fine... Now, yesterday, I had a first... I could actually SMELL gas from the carb, so maybe this ones got a bad float... or can vacuum alone pull gas from the bowl thru the overflows?????? There is some sort of "return line" that goes from the top of the fuel filter/sediment bowl... today I'm gonna see if its blocked, perhaps I'm getting TOO much fuel pressure if it is??? Now, DrJ had this theory that the valves had dropped into the seats, making the stems too long, causeing the exhaust valves to stay open too long, causing loss of power.... thisa wouldn't make it RICH, would it? I haven't measured the clearance, this seems like just too much of a longshot. In the back of my mind, all the same. BIG DUMB QUESTION... the mixture screws are only relavant for IDLE, right? not general operation? That is how I understand it, I'll feel pretty dumb if turning down some screws fixes my shit... Another... doing the equation says that 600 cfm isn't undercarbing a 429... now this aint a drag motor... But is there such a thing as an engine that pulls more vacuum than a carb can handle? wouldn't that result in a LEAN condition?? Whats envolved with leaning down the carb? new metering rods? What kinds of things in general causes a rich condition??? I wann run over the entire gamut. Thoughts? ideas? Thanks,
my holley double pumper w/o a choke runs rich on startup, gurgles, chokes, wants to crap out for the first couple seconds.. you got a choke on it? do you have to give it a couple few hits of gas on startup? if it runs cherry after warming up perhaps that could be *part* of the problem...
Huh... I can get it to start without using the choke, takes two attempts, but I can... That automagically indicates I'm already a bit rich... I tried setting the choke when it was acting up, makes no difference... It runs as can be expected until warmed up, runs fine a while after... but if ya shut it off and try starting again, then trouble starts... or, if running fine, then idling in traffic... same ting. Got plenty of coolant in there, temp gauge NEVER gets above quarter scale...
The mixture screws on MY Edelbrock were too lean and caused a popping noise when I'd let off the gas, and sometimes when just cruising on the highway. I thought it was ignition until I richened the screws half a turn. That isn't YOUR problem, but the mixture screws do affect it off idle. I wonder if Teflon is a bad material to make the spacer out of. I think you are supposed to find something that doensn't conduct heat. If teflon didn't conduct heat, they wouldn't use it on frying pans. But that is just my guess.
Deyo, teflon is actually an excellent insulator. If yer fryin pan teflon was a half inch thick like my spacer, yer eggs 'd never fry. Teflon on the pan is so thin, the heat of the pan will still radiate thru it... yet let the eggs slide off...
J, The rule of thumb for air/fuel mix is 1-1/2 turns. Turn them in until the screw just seats. Don't crank on it, it's a needle and seat and you'll kill it. Then out one and a half and see how she runs. Be sure and count the turns in when you seat them, for reference. Fine tune from there. I once had the same lean condition (popping) as Deyo, same solution too. You have the opposite problem. Make sure the return line from the filter isn't blocked. That's your pressure regulator. I'll be at Skreech's shop friday afternoon. Where are you going to be? Hit my cell. I want a peek at it.
Another one to add to you old caddy bag o' tricks. I've had to replace the vac advance on my 64, my 65 and a buddys 64! All three cars ran ok then started acting weird then would run ok etc...I can't remember the part number but I was able to get them from NAPA with no prob for cheap. Just a thought. Worse comes to worse I will pull the carb off my 64 which was running bitchen til I F*%#ed up the the motor trying to change the water pump. This carb was/is working fine so as a last resort for troubleshooting I can pull it and send it to you if it comes back to me as recieved. I will be out of town next week but could probably get it in the mail by early the following week. This might help isolate if the carb is the fault here or not. Are you coming up to Billetproof as I could possibly bring it there with me too. Ted
Bus, thats one of the things I was gonna check today, blow some comp air into that return... I should be around Friday till the late afternoon, I'll give ya a call. I set the screws for max vacuum with a gauge, once I'm not spraying gas, I'll try backing them down. So, I'm still on the fence about replacing the fuel pump with a stocker or electric, what do we think on that one? I've got two carbs, they behave the same, if not just similar. -J
This may not even help....but, I put a brand new Edel carb on my sis' Trans Am, On start up it ran fine no issues. After warm when you shut it off it wouldnt want to start back up. When it did it ran like shit. What the prob was when you shut it off, the choke butterfly would close, so when the engine was warm it wouldn't want to startup. I locked the choke open and it has been fine ever since. Just a thought.
Leaking fuel pump cuold be dumping gas in the oil, when the motor gets hot, the gas in the oil starts to vaporize,makes the engine way to rich. I saw this a couple of times over the years when I had my shop, if the oil smells gassy, change it and see if it helps, just a thought.
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