TROUBLE IN240 land please help ka24de

[fenderfatstrat6]

****** I know this is long but i felt i needed to be very thorough*** please help

Hey friends I am completely at a loss been messing with my 1991 240sx ka24de since the first day it was salt free and warm.... ok here we go ...... I started it up any time the snow would melt over the winter started like a champ every time... i take it out on her spring maiden voyage and it was good for about 5 miles then suddenly it starts idling really rough like so hard if i said ahhhhhhhhh loud in the car it would sound like i was bouncing up and down. so i say well its got to to be it needs a tune up or just to be driven a bit b/c it wasn't run hard over the winter just idled and reved for a bit . so i drove it ten miles to my buddy's place and it surly didn't feel like it had the power it once did. he thought it might be the injectors so we took them out cleaned them off popped them back in and the idle got violently rough and it wouldn't want to stay running unless i kept on it. so i had no choice but to drive it home pedal all the way to the floor and i was barely getting 80 out of her. it used 1/4 of a tank of gas for 10 miles back home WTF... next i think its the injectors so i go get 2 complete sets from the junk yard doesn't change anything, then i do plugs wires o2 censor cap and rotor still nothing changes. i was told by a 240 guy to check the oil it might have gas in it if i used that much gas. sure enough i changed my oil i kid you not 3 gallons of fluid gas/oil came out. yadda yadda i pull ecu read the code its reading knock sensor so i go get one from the junkyard, nothing changes, try another ecu nothing.. i tried to look over the vacuum lines the best i could didn't appear to be any issue with them/ also did the carb cleaner test with them. im about to give in to a raping at my local garage to get this thing fixed so as a last plea for help before my wallet takes a beatin' i decided to see what you guys have to say.I would really appreciate any educated input you can give me !

[UNVMY240]

Tap on the MAF and see if there is any change. Also if u have one put a noid light on the injector connector and see what your pulse looks like. Sounds like you are dumping fuel. You are only using NGK spark plugs right? And last question, what does your exhuast out the tail pipe look like? Black, white, clear, none? that could help us too.

[fenderfatstrat6]

tap on the maf while it's running? i have the higher end ngk l plugs in .... it is thick and white but my coolant is up i have been monitoring it. i called a shop today and described my problem and they said the same thing about dumping the fuel.

[verSat1l3]

What do you mean by dumping the fuel? I thought the unused fuel went back to the tank via the return line. How does gasoline get "dumped" into the oil?

If you managed to drain 3 gallons of fluid out of the oil pan then you have real issues. Did the oil look milky and brown like chocolate milk? You could have coolant in it which could be a cracked head or block, or a blown headgasket. How much coolant is in it now? If that motor was holding 3 gallons of fluid in your oil passages/pan your valve seals are probably shot from the leakdown from above. They seal out a certain amount of oil, but won't take a flood like you are describing. Thats why its important to not overfill with oil.

[fenderfatstrat6]

well this is what the dude at my local garage told me and his term was dumping fuel. I am positive that its not getting put back in my tank b/c i am almost on E and i have only driven it what 12 miles total so that gas has got to be getting half *** burned or filling my case up. l have never over filled this car with oil so that can be left out of this equation. the oil looked like normal oil just super thin and smelled of gas it wasn't milky at all. so thats why i was overruling the idea that the head is blown

[verSat1l3]

I still don't know how the car is going to dump fuel into the oil...

Are you leaking fuel out of the rail at all? Bad o rings on the injectors? Hole in the gas tank? Split fuel line? Run it and check for leaks.

[fenderfatstrat6]

no leaks in the rail. when i took the injectors out i checked out all the rings and they looked good. no leaks my drive way is bone dry.

[Vegascorbin]

Are you running any kind of oil cooler and got the lines crossed?

I am also at a loss to explain how that much gas is getting into the oil.

The olny time I have seen gas milage go that bad that fast was when the Cat was plugged. But that does not explain the gas in the oil.

If your injectors wer putting that much fuel in the engine then you shoud have large amounts of black smoke out the tailpipe.

Sounds like you may have to tear it down to find the problem.

[UNVMY240]

Gas can get into the oil via getting past the rings on your piston. When an injector fails it can drip or even trickle fuel into the cylinder washing the walls lowering the compression in that cylinder. And whats just on the other side of your piston??? Thats right the oil pan and crank and whats in there??? Right again your oil.

Do a cylinder compression check on all cylinders. Pull the fuel pump fuse and and check each cylinder at one time. Dont pull all the plugs out and try and get readings. Doing so will affect the test (causes the engine to turn over too fast cause of no compression) Get some readings, I bet you are low on at least 2 cylinders. I think avg compression should be around 160/175 psi I believe. I might be wrong on this please check before going with these numbers. This will help with figuring out whats going on. It will tell you want cylinders are having issues.

[hugesack]

check your pcv valve operation. you shouldn't be getting that much blow-by unless your rings were shot. if they were good before that is unlikely. hope that helps

[srpowered240sx]

try running the car without a maf plugged in, might be a bad maf. i had a injector issue where it was at full spray all the time, ended up being a bad ecu, but you said you tried that already.

[fenderfatstrat6]

this car is completely stock never even been messed with just had regular mait done by dealer all its life from the last owner and i have had it for the last 3 years continuing doing regular mait on it at home. ..... ok on to compression i did the compression test where i took out all the plugs and it read 175 on all cyl's. i previously did the test what i thought was wrong and did it where i did one cyl at a time and my highest reading was 120 and the lowest was 70. but i was told by several people thats not the way to do a proper test. i tried another maf already but i know a kid that has another one so i can try it also. thanks to all you guys responding it means a lot!

[UNVMY240]

Was your last compression tests after the fuel problem the 120 and 70 psi? If so the cylinders with 70 is the problem. I still think you have bad injectors or ecu. Was there any sign of drivablility at all before this started? Did you put any cleaners removed anything and put back on? Something is not right. You said u live in a salt state... do u have any corrosion on the injector harnesses? Corrosion and electronics DONT mix. Start checking grounds and connectors for corrosion, even the ECU.

[fenderfatstrat6]

figured i would post this vid of it


Modified by fenderfatstrat6 at 9:58 AM 5/16/2008

[fenderfatstrat6]

wahoooooooooooooooooooooooo!!! ok so its all back up and running again. ... it ended up being i had another bad injector so i swapped them all out to another set i had and it runs awesome now thanks for all your help guys!