Helpp my injector is stuck open

[Caden.]

So my ls400 has currently been down since December it was running fine one second and then the next it was spraying fuel out the right side of the exhaust and blowing white thick smoke everywhere that smells like gas. I’ve repaced my ecu, injector, o2 sensors. Im stumped and can’t fix the issue.

[Jeremy M.]

Is it only out of the right (passenger) side exhaust tip? I only ask because that strikes me as odd, seeing as how the right and left exhaust tips are connected further upstream.

I saw that you suspect an injector is stuck open, so I'd suggest checking your oil, smelling it for gas that has leaked through your piston rings from flooded cylinders, and if it smells off, changing the oil at least one time, possibly multiple times to get rid of any fuel in there.

Check the signal to each injector with a multimeter, unplug each connector and have an assistant spin the car over to get a DC voltage reading and to check that there isn't an odd short keeping your injector open.

If you can, attach a video of any relevant symptoms, describe the exhaust smell in more detail, etc. in order to get a more complete understanding of what's happening.

[paulo57509]

Typically, white smoke indicates moisture or water (black smoke would indicate fuel, blue smoke oil).

A little white smoke is normal when you first start the engine after it has been sitting overnight and soon goes away after condensation in the exhaust system has evaporated from the exhaust heat.

If you're getting a continuous, huge cloud of white smoke that doesn't go away after a few minutes of warm-up, I would suspect you have a head gasket issue.

[300EChuck]

You guessed it.  Injector stuck open.

I have an extra good (tested 4 different ways) injector for this.  Price is $50.  Has been rebuilt and is the OFFICIAL Denso injector.  Bosch doesn't make one for this.  Nor does Standard.

Our business is called Fuel Injector Specialists.  I also own a 1990 LS400, which is how I happened to be here.

Suggest you pull all the injectors.  Not too bad a process, the forums have a helpful video available.  ALSO PULL THE COLD START injector, which is at the bottom of the plenum.  See why I recommend pulling the Intake?

You could buy the one good from us, or send in all 9.  $20 each complete rebuild, with pictures before and after.  Or, not do anything at all, and wipe out those  3 cats.  Phone number is 303 456 0789.

 

 

[300EChuck]

Head gasket is possible, but you will smell antifreeze out the exhaust, not gasoline.  To blow a head gasket you would need to massively overheat the engine, as in pegged temp gauge and steam billowing everywhere.

[300EChuck]

I love the back and forth on these forums.

You'll get some white smoke, but only if the temp is way below freezing and that now hot moisture in the exhaust meets cold air.

How can a stuck open exhaust blow the cat on the other side of the engine?  In the intake process, there is always a bit of intake fuel mist coming back up through the intake valve before the valve completely shuts.  Enough can kick back through to the other half of the Vee to richen up every cylinder.

Newer cars don't use an EGR as such.  Valve timing can be varied enough to pulse a bit of exhaust back into the intake.  Thus, lower temperatures.  TAH DAH.

Great idea until low tension piston rings and direct injectors happen to be present.  Best tool I ever bought was the kit to blast the back of the valves after the intake is off.  Hello Audi V-10!!  Takes care of my boat payment.

Been using Walnut shells.  Car Wizard likes a charcoal type of mix.  He has info on one of his videos.  Haven't tried this mix yet.

[RX400h]

I believe Audi service techs use walnut shells for cleaning carbon buildup on DI 2.0 engines, every 60,000 miles. This is partially why I don't own an Audi.