csimpson1

Not really sUte how to describe this. When I hit the gas it sounds like the carb is swallowing tons of air while the car is running terrible. Started doing it after driving awhike. And now it wont even start. Took any twobweeks for it to get this bad. All the wrote trying to figure out the problem. Definitely seems to be carb. Carb was professionally rebuilt the day before I got to start driving it. And its been two weeks and rough the entire tinw. Now no reaponse. 84 trans am. 350 that hass been bored thirty over. 600 cfm edelbrock. Has spacer. Maybe 1 inch spacer. On a edelbrock intake. Motor was just rebuilt. Brand new mechanical fuel pump. Distributor could be off. But carb seems to be acting up.

Thanks in advance guys!

pancherj

Is the choke closed and staying closed?

Ozz1967

iTrader: (4)

Need to know a bit more about it. Year, make/model etc along with anymore mods done to it. You have an 84, but with the edelbrock I'm assuming you've swapped out the distributor for a non-ecm controlled unit and have disconnectd all the relevent electronics?

csimpson1

Regular dist. Stock I mean. Pontiac trans am, yes its 84. Choke opens well and its worse when the choke opens. After I drive it for awhile its gets so rough it dies. Wait 20 mins runs like a champ for awhile and then sies. Choke light is on in car. No check engine light.

csimpson1

Seems air/fuel mixture is way off. Tune front ports? Dunno how to do that. If top of carb is covered with a buddys help and throttle is raised it sounds really good. Take hands off and tries to die. Carb was recently rebuilt . IM stumped

pancherj

If it is the stock 1984 distributor, it needs a computer to control the advance. To run a regular carb on our cars, you need a vacuum advance distributor that has internal weights and springs that control the rate of advance.

How did you set your timing?

csimpson1

I disnt. And I would love to read how. I have a timing gun. But I didnt set it. And distributor has vaccuum advance hooked up. Would timing cause the carb to sound like that

pancherj

It sounds as if someone already converted the car to an older style distributor.

I would start by checking the timing (you either need a timing light with a dial or a balancer on your engine that has numbers all the way around it). Unplug the vacuum line from the distributor and then plug the line (so there isn't a vacuum leak at the carb). Turn the idle down as low as it will go sithout stalling. Check the timing...what is it? This would be your base timing. It should be somewhere around 12* advanced. Now, rev the engine and see where the maximum advance goes to. You may need to give it a few good trys (4000RPM) to see what the maximum is. What is it? This is your mechanical advance. Now, plug the vacuum line back in. Does the advance increase? It should. You should idle somewhere around 40*.

If you are restricting the airflow into the carb (with the choke or your hand) and the engine runs better, that probably means it is very lean (or the timing is off).

Ozz1967

iTrader: (4)

This could also mean that there is a vacuum leak which could be causing the timing issues. Plug all the vacuum ports on the carb first. See if things get better. If they do, then you've got a vacuum leak that you need to fix first.

Once you've verified that, keep them plugged (Except for the vacuum from the distributor), and check your timing per the above statements. Now, when you adjust your lean/rich to get it set right, you'll probably be readjusting your timing again anyway.

csimpson1

Will check timing and all that when o arrive at home. I am a bit confused abt the advance. I'm not sure what it is or what it does. If that was to be explained, it would be a positive. Thanks for all the help guys. I was told the gasket between the carb and intake culd be blown because of the way of sounds. Is this an often thing. Or no?.

csimpson1

Update. Set timing to 10 btsc. Ran great. Better than before. But as soon as it gets driven abt 10 miles it does the same thing. Tries to die. Hesitates and stalls. And at idle it barely runs. And when this is happening. I can smell tons of gas. I'm stumped. Is it possible, with my header setup, the spark plugs wires are gettin too hot? That would keep spark from entering and use way too much extra gas. If this is possible. How do I test this?

pancherj

Doesn't sound like it is spark plug related. You said you have a brand new mechanical pump...what one? There isn't an original electric pump still in the tank is there? Can you measure fuel pressure?

Edelbrock carbs are notorious for heat soak. How hot is the carb after you drive 10 miles? What is the spacer made out of?

csimpson1

It look to be same material as carb. Looks like it is the one you get off the shelf at autozone. And what is heat soak. And I don't know about the temp. Need to get my temp gauge hooked up in my car which is something else I need to ask. Lol. And I have a temp device. Will check it tomorrow. Def seems fuel related. When the car is cold and off. If I take the fuel inlet on the top pass side of carb where a filter usually is. It will continuously spew gas. Idk if tha.t is normal or not. Another thought. Culd it be accelerator pump on carb.? When its riding rough, it feels like the pump culd be bad, from what a mechanic told me it would sound like if it was bad. And no pump in tank. My new fuel pump is mechanical on the block. Has three total lines. Two rubber slip ons and one steel threaded line. Was $18 at napa.

Ozz1967

iTrader: (4)

On the fuel pump, the new mechanical one. Are there three ports coming out of it or only 2? These car's fuel system is designed to run with a return style fuel set up so this could be part of the problem.

Also, you say if you take fuel inlet off, it spews gas. Try uncapping your fuel tank, then do that, does it still spew gas? It shouldn't because you have just depressureised the system.

csimpson1

It doesn't spew with cap off. Thanks! And it has three lines. Return, fuel line and then line to carb. I don't have a filter. Not in the carb like on the quad jet. Or an inline filter.Culd that be a problem. ? And what is the line, its a steel line, going to the back of the carb. But after driving it 8 full miles it hesitated and died. Wouldn't start back up for an hour. Then fired right up and ran for abt 5 miles. Engine was operating temp and it died. I don't kno of the heat has anything to do with it. But culd it be? Like I don't have a temp gauge so I don't kno if its over heating or not. It def culd use some water. Refill tank is empty.

pancherj

Try driving it with the gas cap off. Maybe it is building up pressure? The original third gen caps were not vented (they vented through the charcoal cannister). I still think it might be heat soak in the carb. After driving, can you put your finger on the carb and keep it there? The Edelbrocks have a very small fuel bowl (not like a Holley). Doesn't take much for that fuel to overheat and boil.

csimpson1

Tried gas cap and no good. Stayed the same symptoms. And I will try the heat thing tomorrow. I figured out on my distributor two top pins were broke and the contacts for the rote button to cap were terrible so I got new distributor cap and rotor button. Will see how all of that does tomorrow. Thanks a ton!

csimpson1

Update.
Can't get more than about a city block before it runs like crap. It definitely seems heat relatedd. Plan to check thermostat to are if its closed and causing car to overheat. I do not have a temp sensor because the p.o. puut a different alternator bracket and it covers where that's supposed to go. Where can I put a temp sensor somewhere else. Also there as something in my intake on the front, right by the temp sensor base two vacuum ports and looks to be an electrical port below them. I'm not sure what it is. Should the vacuum lines be capped? Will add picture after this post of this unidentified part.

I was told there can be heat soak. This is when the gas is getting too hot. ? And told to replace the base gasket on the carb. Should I do that? My motor bay gets so hot everything in there is too hot to touch, even plastic and rubber. I feel its running way hot and wondering what all this could cause and where should I go from here.

Where does the map sensor connect to. I have it on a port that comes off of the intake, right in front of the egr valve....

Thanks for all advice and sorry for many question post. I'm getting frustrated.

GTAwheelman

couple days ago i had a similar problem with my 85. turns out i arched a bunch of plug wires on the headers. however i dont have this heat issue. in the drivers side head between the #1 and #3 plugs is a spot to put a temp sensor.

you can get a mechanical temp gauge from just about any autoparts store for about $20.

scooter500

iTrader: (1)

Way hot... well, is your thermostat opening (if working you should see temp gauge move up to normal operating range after a few minutes of driving) and/or radiator fan working right? What style of air intake do you use - original style or an after market 14" chrome cap on top of the air filter (a round chrome cap basically dooms your engine into sucking in hot air)?

csimpson1

took thermostat out. is there a way to check to see if its bad? it doesn't physically look bad. but ran it out of gas and now at the hospital so unable to do any troubleshooting.

scooter500

iTrader: (1)

As long as it is out, put the thermostat in a pan of hot water and it should start to open around 195 degrees F (for a stock thermostat). if you don't have a way of checking the temp in the hot water then it'd be opening somewhat before the water starts to boil.

If it is back in the car get some help to start it with a cold engine, keep it idling and watch for the radiator fluid to move after taking off the radiator cap. No movement means a stuck thermostat.

There's more at this link on page 39:

http://books.google.com/books?id=mNU...page&q&f=false

csimpson1

Took thermostat out. Ran it without one. Problem persists. I believe the choke is closing and holding the flap shut. How do u get it to stop doing that. Even at idle when I'm messing with the carb and I rev it up, the choke flap will hold close. It does stick a bit. Is there a way to fix that.? And where is the best place to wire the choke 12v wire.?

scooter500

iTrader: (1)

As long as your car was a carb'ed car before then you should have a 12v choke wire already to connect on the passenger side of your carb. Here's a picture of my choke wire with a broken connector; sometimes it came off and my choke would not work right. I eventually got a new connector and the choke wire never came off again. https://www.thirdgen.org/forums/carb...hoke-wire.html