i have a 85 trans am with a 305 w/rebuilt heads and a summit 1105 cam,edelbrock 1405 carb and stock intake.
after i drive for about 20-30 mins, temp gets to about 200-220 the car wants
to get a low idle and then will stall out. to get started back up i have to keep the gas pedal to the floor and crank for about 20 seconds then it will start back up. this doesnt seem normal to me, never happened before cam swap...anyone have any ideas on what to check for?? thanks in advance.

 

ok im not the most seasoned person around here so feel free to get a second opinion but my thought would be that maybe ur running to rich and need more air to match up with the bigger carb and cam combo
thats what i would say

 

well the carb was on before the cam swap, only thing that was changed was cam, lifters and valve springs. thanks for your reply
any other suggestions would be great

 

Running ritch would keep the cylender temp down not heat the motor up. Sounds like an air dam proble. There is alot of cases where people go from stock 305s to mild 350s and develip overheating problems. More power means more heat, the cam swap could have caused it. Check the air dam under the front of the car.

Edit: Though about this after i posted, With the cam swap you could be running lean now. It can raise the cylender temp and cause a motor to overheat.

 

ok the problem is not the car overheating, just after i drive it for a while 10-30 miles the car wants to almost stall out at idle and if it does stall out thats when i have to put the gas pedal to the floor for about 10-20 seconds then it will start. any help on this would be great.

 

the only thing i can think of is maybe there isnt enough air comin in cuz i have a firebird and the stock air assembly is very restrictive...or perhaps it wasnt tuned properly after the new cam....thats my 2 cents

 

Get your computer retuned for your new parts. Right now your car doesn't recongnize what was done to it. Therefor it will run like cr@p.

 

That would only be true if any of the computerized components are still there, such as the distributor.

Check for vacuum leaks.

 

all the computer stuff is gone. ive checked for vacuum leaks, cant find any.
yesterday i hooked the vacuum advance to the full manifold from the ported
and that seems to have changed this problem. stopped twice and tryed to restart and started back up. if this was the problem or not im not sure, but it still wants to run different when it gets warmed up.

 

just an update, orginal problem is still there. havent driven the car in 3 weeks, took the oil pan out. tried running it yesterday and the problem ive noticed is the idle gets low and the oil pressure drops to about 5psi
if the gauge is right i dont know. im lost. timing doesnt move, fuel pressure holds at 5 lbs any ideas of what to check for would be great. thanks again in advance

 

maybe time to check oil pressure at the switch. low pressure cuts off fuel pump voltage if i recall correctly.

 

Two questions:

1) How was the carb adapted to the stock manifold?

2) What fuel pump is on it? You said it maintains 5 psi, but are you absolutely sure it has that pressure when it dies?

The oil pressure switch would only be a factor if there is an in-tank electric fuel pump. From what I understand, an '85 would only have an in-tank if it was an L69 (HO), or it was added by a dealer to solve a vapor lock complaint, or was added by a previous owner.

It sounds to me like a lean condition as well. That could be due to vapor lock, boiling fuel in the carb, or a vacuum leak.

It could also be a weak component in the ignition that fails when it gets hot.

 

has brand new fuel pump from oriely(stock) no intank pump.
edelbrock on stock manifold w/adapter.
brand new proform distibutor w/vacuum advance
car runs great when cold then progressivly gets rougher idle and then after warms up to 190ish the idle will get low and if i dont catch it, it will stall out then wont want to start back up. i think it is something very very easy im just missing. keep the ideas coming, thanks again

 

All to often a problem area. Double check there for leaks, especially a gasket that doesn't quite cover both the manifold & adapter.

 

just run some ThreeBond (it is like a grey gasket silicone) on the face of the gaskets it workes heaps well when you have thin gasket faces or small air leaks. (let it set for atleast an hour before starting car).

 

ok i pulled the carb and adapter plate off, the gaskets look fine but im gonna pickup new ones anyways. i was also looking at the egr block off plate thats on there. was there before the cam swap and i didnt take it off, i was wondering if that would have anything to do with it?? also i rember when i had the intake off the ports for the egr were open not blocked off. any other thoughts would be great.

 

A leaking EGR blockoff plate would cause problems.