Sup everyone, Im trying to diagnose a problem with my 1986 z28 (305). A mechanic recently found out that theres fuel getting into the oil, and that the engine was flooded with fuel. After changing the oil, and getting new spark plugs the car ran fine. In the course of one week the car began to bog down more and more with each start. My guess is that it's the cpu, or malfuctioning injectors. Any help? thanks in advance.

 

id also like to add there is a strong smell of gas looming when i attempt to start. I ran a forum search and problems ranged anywhere from bad injectors to vacuum lines, just looking for a more accurate diagnosis. Thanks!

 

we need more info on your car, such as is the motor TBI or TPI, have you done any mods, did you pull codes, if so what were they?
a bad fuel pressure regulator can cause fuel to get into the oil.
i would not drive it until you find the problem & get it fixed, i would not even start it unless i had to. a bent rod from being hydraulically locked up is not a pretty site. bearings washed out from lack of lubrication are also not pretty. then there is the possiblity of a fire which would be very bad

 

305 v8 tpi, no mods, didnt pull any codes,

 

Try pressing the gas pedal all the way. See it that helps.

 

sounds like a leaky injector or two .. or three...

 

Can these be cleaned or should they be replaced?

 

they should be tested before you go about replacing them. Might not be leaky injectors, but very well could be.

I believe the procedure to test them is to take a fuel gauge at the rail, power up the car, or atleast get the fuel to the rails by priming the fuel pump, if there's decreasing fuel pressure while the car is off (over the course of a couple seconds, minutes, hours) then you've got a leaky injector. You can take the injectors out as well I think and test them, not sure on the procedure though.

This might not be the right information for the test though! I dont have a TPI car and havent learned too much about them, but I do believe this is what you try.

 

my car currently wont start either, when i try to start it, i also smell gas, but my fuel lines have no pressure, when i depress the shrader valve i get no squirt, so im getting my car towed to the local high school and they are replacing the fuel pump for me (they are going to diagnose it first, to see if its even my fuel pump) i havent checked to see if my car has gas in the oil yet considering my car is 20 miles away and its hard for me to get out there.
also when i give it gas while trying to start it, the engine seems to have an even harder time trying to start. i have an 1986 305 tpi also, its 124k miles, maybe we have the same exact problem. check to see if you have any pressure by depressing the shrader valve after the fuel pump has primed, remember it should be around 45 psi, which is more than your tires, so if your tires give out more pressure than your fuel rail, then that means it has low pressure.

 

WaaX, I remember you making a thread about your problem, but I cant remember if anyone suggested to check your fuses.

There's a fuel pump relay fuse, and I believe there's a left and right bank injectors fuses.

You should check your fuel pump relay fuse before you go about getting the fuel pump replaced... a lot cheaper, and easier on the poor kids at the high school... I used to be one

 

haha thanks, yeah ill check that out, i can only wish for it to be a fuse *rolls eyes*

 

great, autoshop teacher wont take the car in, explained to him exactly what ive done so far, and he said that if its the fuel pump, then he doesnt want to bring that project in because he has to subject over 100 students to gas fumes, so blah, my only choice now is to do the back door method, im not dropping my tank, im not skilled enough.

 

haha, sorry, posted that in the wrong thread, stupid email notices, sorry..

 

Hey Waax, before dropping in a new fuel pump, try replacing the oil pressure switch. It's a lot cheaper and easier than replacing the fuel pump. They range anywhere from $10 - $20. If that doesn't help the situation, then I would tackle the fuel pump.

 

By the way, fakz, I would double check to make sure you are really getting fuel in your oil. If you are, you have some issues. One possibility could be a leaky intake manifold or gasket. I took my intake manifold off of my tpi firebird and found cancer throughout the manifold, deep pits in the aluminum. I ended up having it welded. That's an issue GM aluminum manifolds had. That could be what's causing fuel to get into your oil. The only other option would be a blown headgasket. But if your head gasket was that bad, you would notice it. You would also have coolant in the oil.

 

blah, i checked the smell of my oil, gas!

dude, figure out whats wrong with your car, because when i figure out whats wrong with mine ill tell you and hopefully it will help you

there is only one major difference from me and you, my car doesnt start and i dont have any fuel pressure >.<

fuel pressure regulator?

how much do those cost and how can i check it, along with where are they located...

 

It's definitely not the fuel pressure regulator because you don't have any pressure at all. I would try an oil pressure switch first. They're only 10-20 dollars, and easy to replace.