Baught a 1991 firebird V8 305 yesterday, for a dance and a song basically. Half of my paycheck, guy said he sold it because he had way too many problems with it, i payed 100 dollers for the whole thing, and it has brand new flowmaster exaust, tires, suspension, and everything is in amazing shape.

well, almost.


For one, car is a b**ch in a half to start, its very tempermental to start. He said that 2 cylanders are dead, though i havent found any reasons to say that, when it runs its well balanced and sounds like a nice full v8, not a v8 trying to be a v8. and, both pipes, which are ssplit between the 8 cylinders have equal pressure comming out of them, unless one cylander is out on both sides, and somehow the engine isnt rocking like crazy because the dizzy sequance dont allow proper balancing from what ive saw in my haynes manual.

ok, next problem, cooling fans dont come on, though ive read they dont come on till around 220-250 deg, and i cant get the car above 220deg, which leads to next problem.

Car will randomly stop running when it gets to around 220 degrees. sometimes itll be a tad over, or a tad below. if the cylanders were bad, it shouldnt shut the car off if it ran cold. its easier to run warm then cold. No check engine light, no codes thrown out by the ECU(or whatever gm calles them). Jus flashes code 12, so, it isnt anything in the electronic system.(also should mean coolent temp sensor should be good, right??)

and, car wont start untilit cools down to halfway between 220 and cold.


Ive done all engine checks, theres no air bubbles out of the collent(meaning crack block superheating the coolent, overheating the engine. engine dosnt even have a chance to over heat) oil is fine and decent looking, though needs a chance. no blowby out of the crankcase that has the oil cap on it, also meanin that IF 2 cylenders are dead on opposite sides of the engine and somehow balance out, that the compression SHOULD be ok, which would probably narrow down the bad cylanders to vlaves, or sparkplug, or maybe clogged injectors. ALSO, there is no blowback in the intake, which would mean the valves arent seated right, so, not sure if it rules that out, just some more info.

Havent had the chance to pull the plugs to check for fouled plugs, will do tomorrow. also, plan on renting a compression reader from autozone to test that. Pressure should be around 130ish, right?

so, a big long explaination of whats going on.

I probably will become a perm membor of this board. also a member of redpepperracing.com, but my 86 hatch is on its way out, running on 2 out of 4 cyls, and it ISNT balanced. that was my beast car.


Id appreaceate any help i can get, thanks.

 

first thing I would check is your fuel pump . I had the same problem with an 84 z28 car would run fine then all the sudden die and wait untell cold to restart. I checked the carb one time and it had no fuel coming out of the jets when I pumped the throttle also check to see if your return line on your fuel pump is cloged let the car warm up and take the gas cap off if you hear a big sucking sound that could be it(solution would be to buy a vented gas cap)

small block pumps at schucks are $17

if it sounds like it runs fine then it probably does most of the cheap cars that I have bought had something majorly wrong with them according to the previous owner and most if the time its nothing big

I bought an 86 trans am for $300 with a "rod knock"
according to the owner turned out to be loose torque converter bolts $1700 profit in a half hour

 

Hmm, thank you, havent though about that happening at all. Ill check the pump for pressure, but why would it go out after running for around 15-30 min, and why usually around 220 degrees? could be that thats jus my cars normal operating temp too..

If i do get a new pump, i read somewhere that 50 psi instead of stock would insrease hp by like 20, is this true?

 

Im really not sure about hp increase

is it a tpi, tbi, or carbed mine was a carbed car

the problem usually took place about a half hour in to a drive

220 is not too hot for these cars but I would put in a 180 thermostat and make sure you air dams are in place


if your fans still dont come on wire them up to come on when the key is on

 

was gunna wire them to a switch, put them on if it got too hot, wouldnt be a problem.

Air dams? wats that?

its tuned port injection[sic?]

it usually takes place between 15-30 mins, regardless if im driving, if im driving, if i gun it, itll stop. Have to be careful to not bring it above 2000rpm or around that.

 

I would bet its a fuel problem check the filter also

the air dams are a plastic piece under the front of your car to push air up it to the radiator