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Blue smoke during some accel/idle


badjuju

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81 280zx turbo

Msns-E

283014 miles

 

I have blown about 4 fuel pump fuses in the past month (10-20 amps) and now my car is starting to bog way down and it appears to just go way rich during accel, or what i wish was accel, because i put the pedal down and nothin happens. the engine's sound gets way way deeper and it just creeps ahead slowly accelerating. I have purchased a walbro 255, which I'm going to pick up in about 2 hours, because I've been told two or three times that a fuel pump will start to blow fuses as it leaves this world, and the crappy acceleration just sounds like this is what is happening. However, i just had a scary thought, my weedwhacker burns 1:50 gas:oil, and it puts out blue smoke sometimes... am i burning oil, or is it just running uber rich (the car, not the weedwhacker)

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Well i have a tid bit of bad news for you, and you're on the right track... Engines will blow smoke for many reasons, so here come the 'simple definitions.'

 

Engines that burn oil will blow blue smoke. Large amounts of smoke on startup could be piston rings, or valve seals.

 

Engines that burn coolant will blow white smoke, often mistaken for steam, and is likely from blown head gaskets, etc...

 

Engines that blow black smoke, are expelling partially burned fuel, which can be for any number of reasons, fuel system mis-mamagment, to fuel delivery blockages/malfunctions, or "running uber rich."

 

you were on the right track with the weedwhacker idea, too bad its not a fuel system problem eh?

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K get this ****, yesterday I got white smoke.

 

Car wouldn't start. I got towed home.

 

I get home, and start the car. No smoke.

 

This is what has been happening. Since i was blowing blue smoke, i figured, wtf, i'm probably burning oil. so i put oil in the car before i go off to work, noticing i spilled a little.

 

I noticed white smoke just as I couldn't drive my car anymore due to god knows what.

 

i get home and the engine starts, and there is no blue smoke, and no white smoke. i'm standing over the engine bay, all of the sudden my fuel pressure drops to 20 from 30 psi, running. upon closer inspection, i see that the wire that grounds through megasquirt, is grounding through my sh*tty wiring job, on my fuel pressure gauge.

 

so every once in a while, the fourth injector would just, turn on. and stay on. this would create such a rich condition that i would pop blue smoke. the car wouldn't run anymore because of how much fuel there was in the engine, and i was going slow enough that i could see the oil burning off of the exhaust manifold. so, i don't think i have a blown head gasket.

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Clean that oil spill very well with Varsol or some other grease or oil remover, when the car is cold of course. Usually oil dripped on something does not cause white smoke but a really strong fume that you will notice. You should fix that wiring really soon, just the thought of fuel and a stray spark is not a good thing. You will need to pull the number 4 plug and clean it or replace it since it is probably fuel rich dirty.

 

One other color of smoke not mentioned above is brown smoke which is also too rich and can indicate raw fuel making it out of the tail pipe, but haukenes did a very good job describing what to look for. You can actually get white smoke from automatic transmission fluid getting into the fuel or your oil supply.

 

The blue smoke is most likely the valve guides which have always been a weekness in these motors. Rings going bad would show lower compression and probbaly blow-by which you can see if you open up the oil refill cap and have the car running. If the car has no blow-by then you will see no blowing of air from this area, if it looks like a train stack then you broke some piston lands or have broken rings. If a little bit of puffing then you may have one bad ring set or just some worn rings.

 

Good luck. My outlook on working on cars is always figure out what is wrong before you wrench than jump into wrenching to try to figure it out.

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One other color of smoke not mentioned above is brown smoke which is also too rich and can indicate raw fuel making it out of the tail pipe

 

Yeah' date=' i completely forgot that one, it goes similarly to the black smoke under "partially burned fuel"

 

The blue smoke is most likely the valve guides which have always been a weekness in these motors.

 

Now that, didn't even cross my mind. Great assertion iaconsultants! I didn't realize that the valve guides could lead to that sort of issue, thanks!

 

Well good to hear that you don't have a blown head gasket! Unfortunately, depending on your preferences in engine work, the wiring can be almost as much of a pain! Good luck, good to hear you've got your problem figured out. -Dave

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Yeah well, this is pretty good news for me, It didn't happen during full throttle, if at all, it would happen constantly, throughout the 1-3k rpm it could handle, and when it wasn't happening, it wouldn't happen at all. also, i have an automatic, so there is never a really high vaccuum during decel.

 

in my experience, every time oil is spilled on something that gets hot, it burns off white. the builder of my truck's old engine managed to break off a valve cover bolt (?), so the passenger side valve cover wouldn't seal right. oil would just pour onto the header, creating a white smoke screen behind the truck. also, the first time i changed the oil on my old golf (first oil change i'd ever done) i spilled some oil on the engine, and it burned off white when i was sitting in burger king. in addition, i only saw the white when i was going very slow, like to stop, right before i called AAA. this would mean (since i could still see the blue smoke behind me) that the smoke wasn't exhaust from my engine's combustion, but just exhaust from my engine's surface, as if i'd spilled something.

 

This is all hopes though, i should be able to find out this weekend. thanks for everyone's help

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Three days later, my afr is up at 20:1. I can't accelerate. Basically I'm having the same acceleration issues I was having before, except now it's reading 20 instead of 9.

 

I'm wondering, uhh, what do I do? The resistance on all of them reads 2.7-2.8 ohms, and i'm wondering what my course of action should be... Is there a chance that it's still a bad injector though the resistance is reading right? my fuel rpessure is reading about 20 psi when the car is running.

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