After building my engine, I noticed that after around 400 or so miles, the car would start to hesitate really bad when the engine got warm. Thought it was ignition problems so I got new coil and ignition module. Came out to be that it was the oil. I thought since it was the first oil I placed in it to break in the engine that I wouldn't have this problem again after replacing the oil with fresh new oil. Guess what, after 400 miles it did it again. I check the oil and noticed that it smelled like gas. So the problem is that the oil is breaking down which causes the lifter to not get fully charged, and the valves wont open up fully. So what can cause the fuel to get into the oil? When chip was burned, we ran it and it wasn't running rich nor lean. Appreciate any advice. Thanks

 

I dont claim I know much about anything, but sound to be like you are running really rich. I know you said you arent, but when you run really rich you wash the oil off the cylinder walls and you can see where it goes from here. Just an educated guess but im sure someone else is more experianced in this

 

sounds like an issue with your rings...did you set the motor up really loose (for a possible nitrous hit) or something like that?

 

Ok, if I bought the recommended rings for the pistons, wouldnt the gap be right. Still wouldn't make sence if the gap was for nitrous, cause why would the oil break down that quick in under 400 miles. Figure no one would do that if that was the case. I just now notice that the whole engine is clean except for the AFPR. It is covered in dirt, and I guess it might be leaking around there in order for it to collect dirt there. Another thing I was told was to check the compression to see if its a ring. Is there a certain psi it should be at? THanks again for the replys.

 

Sometimes if there is something wrong with the carb it will drain its self into the motor after sittin over night i seen it befor not sure if you running carb or not

 

better fix it whatever it is before you wash out the rings. May be a good idea to do a leakdown test to see if the rings are the problem already. Also check over the PCV system.

 

no, he's fuel injected...and the injectors don't keep fuel in them.


as far as the compression check goes...it kinda depends on the c/r you have. my 10.4:1 motor is 230-240psi of cranking pressure. my old 9.5:1 motor was around 190psi.

 

C/R is 9.72:1 so I guess 190 or more psi. Another thing is that i did realize that it wasnt holding preasure on the fuel rail when the car was off. it would drop right away. But at that time it would take the car like 7 seconds to turn on. I figured that the cylinder was full or fuel. But now it starts up quick so I figured that the leaky injector got solved. So I guess I check compression and fuel pressure tomorrow. Thanks, I keep you all informed.

 

static and dynamic compression are two totally different things. No way to tell what your cranking compression test will show on a gauge. You need to go out there and do a leakdown test.

 

Hi!
I had the same problem whith fuel in the oil,and the fuelpressure dropped rapidly after turn engine off,i swapped all the injectors and that solved the problem whith the fuelpressure.
Good luck!

 

^^^

The pressure shouldnt drop rapidly. it should be a very slow fall in pressure over the course of a few hours i believe.

 

hmmm...sounds like a leaky injector then?

 

the fuel rails keep fuel in them though unless the injectors are leaking

also when you burned the chip and said it wasn't running rich or lean did you test it at just idle, just wide open throttle or when? you can have perfect A/F at wot but your cruise is just dumping gas or vice versa. same thing with idle and stuff, or even at different rpms. so there is still a chance of having rich/lean condition at some spots.

if your afpr is off because it is leaking or holding too much pressure can cause issues with the a/f ratio as well.

 

Ok, was just checking out car and noticed that plug #6 had come off so car was running on 7 cylinders. So the oil didn't break down to the point where the lifters weren't charging up which was my theory. New question, would running the car for 15 miles on 7 cylinders cause it to get gas in the oil. I know how you all told me that the gas would wash the oil off the cylinder walls and seep down into the oil pan. So is it possible for it to happen within 15 miles. Was thinking about replacing the oil and running it again to see if it would go pass the 400 mile mark which seems to be the time in which the oil smells like gas. Thanks.

 

i dont think 15 miles would have done it, but then again i could be wrong.

On my new carbed motor i had 3 plug wires fall off (re-used old ones till i had time to make the new ones) and i drove it about 5km down the highway and my oil didnt smell like gas. It just ran kinda funky

 

Do you still have that fuelpressure drop after turning the engine off,it still can be a leaking injector.