Hey guys im having trouble with this 302 i built. Soon as i get the truck running the think seems to idle at around 2800 - 2500 rpm. mods- keith black flat top pistons, isky cam .550 lift and 280 duration, edelbrock rpm performer intake, holley 600cfm carb, milled heads and block, stiff *** valve springs from ISKY, and FLOWTECH shorty headers. Im thinking i have a nasty vacuum leak somewhere. Also soon as i let off the gas the truck will die. Any ideas?

 

are you feeding it enough fuel? if it was a vacuum leak then it would idle high, but it shouldnt die. what do you mean as soon as you let off the gas? you mean while driving? whats the timing set at? did you adjust the idle speed screw?

edit: does it make a difference whether you let the gas easy or fast?

 

Now that i think about it i dont think im getting enough fuel. To get it started i have to floor it and pump the throttle quite a bit just to get it to start. It doesnt pop like a vacuum leak either when i drive it. Just seems like anything under 2 grand it doesnt want to run.

 

what year was your truck? did you set the cam timing right? what did the motor come out of? and did you use the correct firing order for the cam? well you said its carbed so pushing the throttle to the floor keeps it from flooding. pumping the gas shoots fuel down into the intake manifold. wasnt your truck originally fuel injected? with that being asked, did you use the stock in tank pumps or a mechanical fuel pump or low pressure eletric pump?

 

I gutted the gas tank and im just running a stock mechanical fuel pump(3-5 psi). motor is out of a 69 mustang. Truck is an 89 f150 originally fuel injected. Im positive my cam timing was set right being that i just checked it when i had to swap timing covers a while back. Here's what im thinking, i noticed last night that on my brand new headers that there was one tube on my headers that wasn't discolored like the others. Obviously this thing is firing on that cylinder. Im getting spark to that cylinder so maybe i have a vacuum leak around that port causing it to run like this? and on top of that im not getting enough fuel. What do you think?

 

the tube that isnt discolored sounds like it isnt firing. which firing order did you use? the mustangs or your trucks? and is it the same that the cam was made for? these things must match together to run properly(or run period).


edit: what was the part number on that cam?

 

Honestly i figured that the firing order for a truck and mustang would be the same since they are the same engine. The engine runs like a champ from 3000 to 6500 rpm so i figure the firing order is right. i could be wrong though.

 

Just found out that the truck still uses its original firing order according the ISKY.

 

well the ho 302 was different. i couldnt remember whether they changed the firing order on your engine or not. but they didnt. could you give the part# of the cam? the reason i ask is that i cant find the cam with .550 lift, i can find .540 and .560 but not .550. and the cams i did find show something about 650+cfm carbs? thats all the site shows and wont give me anymore info on them so if you could look at that, we can give more help.

 

Do you think that since my heads are milled it might be making my intake not seat all the way?

 

i guess its possible. did they do anything to the intake or the block? i reread the posts and you said that you gutted the fuel tank and are running a mechanical pump right? what do you have in the tank to pick up the fuel?