RickBlaine

I am hoping for some suggestions please....my 1991 240sx Hatchback (103,000 miles) was idling poorly....so:

Installed NGK plugs and wires, cap and rotor, and a new valve cover gasket and spark plug gasket set. It still idled rough, but smoothed out on the highway. 0-60 mph times were slow- as the car had no life below 30 mph.

I checked the fuel injectors with an ohm meter. 2 of them were very bad, 2 were good. I ordered 4 matched rebuilt ones from Motor Man Fuel Injection of Michigan and installed them yesterday.

Could not start the car unless my foot was on the accelerator pedal all the way to the floor. Started the car, and grey smoke started pouring out of the exhaust system leak between the cat and the downpipe, and pretty much out the rear muffler and just "all over". Neighbors thought the car was on fire. It is not oil smoke, nor is it coolant smoke- it is unburnt gas smoke!

Pulled the oil dipstick and was SHOCKED to find it way above the full line, and it reeked of gasoline!

Before all this- it idled rough, but ran OK once on the highway. Now it only runs when smoke is pouring out and I am on the gas pedal. If I take my foot off of the gas pedal it dies- so I dare not drive it.

Is it my newly rebuilt fuel injectors? MAF sensor? O2 sensor? Clogged exhaust? ECU? An oil crankcase filled with way too much fluid (oil and gas)?

Any advice would be appreciated. Thanks.

omgosh

The old injectors could have been sticking open filling the engine with fuel until the pressure bled off. It would be wise to check the lower o-ring as well to make sure fuel isnt getting around the rail and injector into the engine as well.

__________________

RickBlaine

@omgosh: Thank you for the rapid response! Tonight I am going to drain the old oil (and gas mixture) and add fresh oil. But the "new" fuel injectors I received and installed did come with new lower o-rings. I did lube them with a wipe of oil before installing.

Primo's Silvia

By any chance u didnt swap the fuel lines on accident??

__________________

ultimateirving

If your getting that much fuel in the crank case something is leaking right into the cylinders and probably getting past the rings.

Take the fuel rail off and turn on the ignition to prime the fuel pump. Make sure nothing is leaking to start. Then you can have someone bump the ignition or give the cas a spin and see if the injectors are spraying evenly.

__________________
Z32 with lq4 swap
Desert Street Scene || Dssevents.com

Kingtal0n

injector oring

cotbu

1.user install error
2.shitty built injector
3.installed larger sized injector, same as 1

__________________

LoverTechnologies "Half Broken Things!"

ZenkiKid

4. Either bad O rings or you crushed the new O rings during the installation process.


Buy some cheap walmart supertech synthetic and run that through the engine to clean up whatever traces of gasoline are left after you flush out your existing oil.

__________________
http://www.nissanroadracing.com/

RickBlaine

Thanks to all- it was indeed a stuck open injector that caused the crankcase to fill up with gas.

You are NOT going to believe this- but I drained 8 quarts out of the crankcase! Yes, 8 quarts....that would mean 50% oil/50% gas. Needless to say I'm pretty sure my engine is clean as a whistle.

Anyhow....I took your advice and bought some Walmart Supertech (cheap) oil to run through. I was sad/mad/crying like a baby when I started the car and lots and lots of blue smoke (no longer grey smoke from unburnt gasoline, but honest to goodness oil smoke) coming out.

You know those guys that Seafoam (into the intake) their cars and create smoke shows late at night? That was me, but without the Seafoam....So I shut it off after 15 minutes.

However the car idled like new- I mean like brand new. I checked the compression and had 170, 170, 168, 165 on the cylinders- so I thought maybe it was NOT the piston rings, but perhaps the valve guides or the valve stem seals.

I spent the night reading up on how to change them....even looked at a Corvette engine conversion....very sad.

Told a buddy of mine who is always messing with older cars- and he used to have a 240sx. He said "...remove your intake and clean it, and clean your throttle body- I bet it is filthy in that some of that 2 gallons of gas/oil mixture you had sloshing around in there may have "backed up" or got pulled in to the air intake system and coated everything." He added that "the gasoline may have ruined the valve stem seals as well."

5 minutes later the intake was off, and it was coated with a thin film of oil. I used throttle body cleaner (on the throttle body), degreaser cleaner on the plastic intake tube, and then Dawn dishwashing liquid.

I thought about the PVC (must be clogged) but figured I would see if I made progress first by cleaning the intake- or blow my engine up and die with it- knowing that I would never mess up another 240sx again.....

I took the 240sx out on the highway for 2.5 mile 0-65 mph runs at WIDE OPEN THROTTLE...late at night....there was a bad smoke show for the first 4 runs....I mean bad, thought I was going to explode.....then it got better...then after the 8th run- no smoke. I mean none.

I checked the oil level again for smells of gasoline- an increase in fluid level, but it was exactly where I left it with the Walmart stuff. So I thought I would park it over night and see if any oil seeped down.

This morning (after parked for 10 hours) I took it out and there was NO smoke at all- not at start up, not at wide open throttle....nothing!

So maybe it was not the piston rings, nor the valve stem seals....maybe it was just all that oil/gas mixture that coated the breathing tube and the intake.

Tomorrow: I will let the car sit for 24 hours and then try again- to see if any oil seeped down- just to confirm.

Next weekend: I'll change the PVC valve out....or at least clean it out with some brake cleaner first.

What I did was pretty stupid. I am dealing with some heavy issues regarding my mother's health right now, and am making a lot of mistakes these past couple of months. I had a stuck open fuel injector but did not deal with it for perhaps 7 days....in that time I gained 4 quarts of gas in my crankcase. I could have damaged my engine. I should never have driven that car while it was running rough- should have figured it out.....

I am hoping all will turn out well- maybe a few more days of evening testing will be OK. I want to thank everyone who responded and offered advice- and guidance. I thank this forum and I hope I can contribute in some way to its growth and strength.

Thank you!

EDIT: How long (time/mileage) should I leave this Walmart Supertech stuff in before I change back to Mobil 1 with a new oil filter? 100 miles? 20 miles? 500 miles?

slider2828

Awesome man! I am glad its working out. I totally understand that feeling of the engine gone. Its like you get a punch in the nutz/stomach pain and how relieved if there is even a glimmer of hope. Good luck and thanks for that story!

__________________
Turn and Burn!

TurboTiger

Glad to see you figured it out. Which method did you use to diagnose the stuck fuel injector? I'm having starting issues and I'm wondering if I may also have a stuck injector.

Don't worry about making mistakes as we've all been there in one way or another. Just learn from them and help out the next guy who is having issues. Hopefully your moms health improves soon.

Kingtal0n

If the injector stuck open, it filled the cylinder with gas. I dont understand how it got from your cylinder, to the crank case. If you fill a cylinder with gasoline, it generally sits there on top of the piston in a huge puddle, waiting to hydrolock the engine.

So two things confuse me here, 1. how did you manage not to hydrolock your engine, and 2. how did the gasoline get into the crankcase from the cylinder.

RickBlaine

Thank you Gents!

@TurboTiger: I used the advice from member "ultimateirving" above- I disconnected the fuel rail while leaving the fuel lines hooked up, with all four injectors still installed within the fuel rail, I turned the ignition on (but not the engine, obviously)- and one injector was leaking fuel. I followed this YouTube video: https://www.youtube.com/watch?v=rCJ5zvY7JCM

If I am violating rules about the YouTube video (and it gets deleted), I apologize. Search YouTube for "240sx Fuel Rail Removal Clip". Rather easy to do....

Just as important, one of my OLD injectors was stuck open and leaking- for at least a week. More importantly, 8 quarts of ANYTHING in your cranckcase is not good for the breathing of that engine.

Thank you for the positive vibes regarding my mother's health!

RickBlaine

@Kingtal: My understanding is that the fuel system holds pressure all the time- even when the engine is off. While it is running, the fuel was getting burned. While the engine was off, gasoline may have continued to drip into the cylinder- not enough to fill it up perhaps, but enough to dilute the seal made by the oil around the piston oil rings...and THAT allowed the continuous gas to drip into the crankcase.

I recall that when I unscrewed the gas cap to relieve gas pressure before I changed out the old fuel injectors- there was no pressure- no "whoosh" sound. That was after it was parked for 17 hours. I surmise that the gas leaked down for 17 hours, or until there was no more pressure forcing it into the cylinder. Perhaps it had been doing that each night for the week I drove it when it ran rough.

That is my theory....but I am not an expert. I welcome other theories....

ceff

No rocket science and guessing here. Remove spark plugs, remove injector harness (plugs) -- key-on to build more pressure to the rail (shutted down it still pressure in the rail but not too much as fuel pump working), look into cylinder with flashlight, crank engine keep looking if its dry. If youll see how pistons become wet -- you have to check orings (first order) and\or stuck injector. Advanced but little bit more complicated test -- remove fuel rail from manifold but do not remove injectors and fuel lines for now. Easy on s13 bit harder on s14. Ignition on -- pressure will build up and you will see what injector leaking. If none found -- put wire between 30-87 contacts of fuel pump relay to turn in on continiously -- make a button with two wires to injector connected to some 12V (any polarity). BE CAREFUL. Then open each injector for 30 secs with injector tip hanged to some bottle -- you can check actual (well.. almost) spray pattern and fuel flow (30sec flow x 2). With some quick touching battery you can check if it stuck open. BE CAREFUL AGAIN. Better make long wires and button to avoid sparks.

https://www.youtube.com/watch?v=Ddnl0pSKx9A its not mine but shows the idea, but keep it connected to factory fuel lines to save a time, just raise it and put a bottle to catch fuel.