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Discussion Starter · #1 ·
Hello, I have a 1980 Datsun 280zx. Car has good compression, fuel pressure, and oil pressure. I put new spark plugs, wires, distributor cap and rotor. Still getting tons of white smoke out the exhaust and even more when I give it gas. Changed oil and it came out grey like clay. New oil is still a funky color and smells like gas. Car fires right up every time, It has cut off once after it warmed up other than that no issues turning and staying on. I haven’t drove it only had it idling outside a few times and it killed 5 gallons of gas. Possible fuel injection problem?? Or valves need to be adjusted?? Not sure what to do next.
 

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Maybe the cold start valve (injector) is leaking?

It wouldn’t be to hard to remove and check it. Basically remove, replug the connection if you need to unplug it, and turn the key to on(not start) to prime the pump. Check for a leak


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are you losing coolant? does the white smoke go away after warming up? gas in oil sounds like short runs, so may be ok once you get it out. black plugs if sooty is rich fuel mix or ign timing. sounds like rich fuel (also a reason for fuel smell in oil) based on gas consumption. The color of the oil is concerning. you may have a coolant leak internally. You can test the rad for exhaust fumes in the water with a test kit (napa has them). You can also pressure test the cooling system, this should be done regardless, if you want to have confidence in all the hoses/heater core/pump/rad/block....

CSV is possible, but temp sensor also likely. Its the smaller dual wire sensor on the thermostat housing. Check the FSM regarding how to confirm the resistance readings. The resistance goes up as the temp of the water goes down. Frequently the sensor fails with a high resistance reading, this tells the ECU is cold and it add more fuel to the injectors.

You should check the readings AT THE ECU, this is all covered in the FSM. Make sure you understand the warnings about how to disconnect the ECU for checking at the 35pin connector on the wire harness.
 

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1983 280ZX Turbo
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Symptoms tend to point to coolant leaking into the oil. Either the NAPA test or a leak-down test on the cooling system would be a good idea - immediately. Don't mess around with this problem, because coolant in the oil can cause bearing damage.
 

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Discussion Starter · #5 ·
Maybe the cold start valve (injector) is leaking?

It wouldn’t be to hard to remove and check it. Basically remove, replug the connection if you need to unplug it, and turn the key to on(not start) to prime the pump. Check for a leak


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Thanks I will check this today.
 

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Discussion Starter · #6 ·
are you losing coolant? does the white smoke go away after warming up? gas in oil sounds like short runs, so may be ok once you get it out. black plugs if sooty is rich fuel mix or ign timing. sounds like rich fuel (also a reason for fuel smell in oil) based on gas consumption. The color of the oil is concerning. you may have a coolant leak internally. You can test the rad for exhaust fumes in the water with a test kit (napa has them). You can also pressure test the cooling system, this should be done regardless, if you want to have confidence in all the hoses/heater core/pump/rad/block....

CSV is possible, but temp sensor also likely. Its the smaller dual wire sensor on the thermostat housing. Check the FSM regarding how to confirm the resistance readings. The resistance goes up as the temp of the water goes down. Frequently the sensor fails with a high resistance reading, this tells the ECU is cold and it add more fuel to the injectors.

You should check the readings AT THE ECU, this is all covered in the FSM. Make sure you understand the warnings about how to disconnect the ECU for checking at the 35pin connector on the wire harness.
Coolant was empty when I got it. I filled it and it has gone down a little, nothing crazy though. Smoke does not go away when it’s warmed up I will have to check that coolant pressure and csv. I will have to look into temp sensor, I don’t have fsm but I have Haynes manual should be in there somewhere. And I’ll have to look into the readings at the ECU this weekend sometime. Thanks!
 

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if you are losing coolant get the napa test, is sample air from the rad thru a blue fluid. IF the fluid turns yellow it indicates exhaust gases in the rad, a and prob head gasket leak (could be other stuff) You can also just leave the cap off, if it starts to violently spew coolant as it warms up there is a good chance exhaust gases are pressurizing the coolant. the funky looking oil is a dead give away.
If you are lucky its just a bad head gasket, however if the engine was overheated (due to loss of coolant) then there is a good chance the head is warped, that would require a GOOD machine shop that knows what its doing to fix it. Its not a SBC, so you need someone that has worked on imports and understands what needs to be done.

I warped head is easy to check with a good straight edge. You may as well start planning for a serious engine overhaul if you find exhaust gas in the rad and water in the oil or oil in the water.

google fsm for a 280z, its online and free (the FSM that is).
 

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Head gasket. Buy alumaseal. Follow directions.
 

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With respect, I'm not a fan of stop leaks for head gasket problems, and have very seldom found them to work. A shop can do a leak-down test or you can do the NAPA test mentioned above (although I'm not familiar with it.)

The one and only way to correctly fix a bad head gasket dependably is to pull the head, have it checked to make sure it's not warped, replace the head gasket and re-assemble correctly.
 

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Under no circumstances should you ever use Alumaseal on any vehicle. It will plug up your radiator and heater core without a doubt. It sounds to me like there are 2 separate problems. Sucking up the fuel is one of them and a possible coolant leak into a cylinder is the other. Temporarily run your coolant level down 1-2" in the radiator, and put your radiator cap on loose so it will negate the overflow bottle. The other reason to do that is you may have a coolant leak into a cylinder and after you shut the engine down, if the cooling system has pressure built up in it then it will continue to push anti-freeze into that cylinder and that can cause some major harm. It can also fill up the cylinder in question and then when you try to start the engine next time it can hydraulic and force more anti-freeze into the crank case. To test for that you can pull your spark plugs, and crank the engine over at the starter by jumping the small terminal to the battery terminal on the solenoid. When doing this be sure NOT to stand by the fender on the RH side. If there is anti-freeze in the cylinder it will be shot out the spark plug hole like a grenade launcher and you'd get soaked for sure. If it hit you in the eye it could cause damage as well. The test from Napa is called a block check. You need for the anti-freeze to be an inch or two low in the radiator to run that test. It monitors the air in the radiator for CO which shouldn't be there unless you have a leak from a cylinder into the cooling system. If the leak has been there for awhile you can pull the plugs, crank the engine over by hand and put each piston at TDC and look at the top of it with a strong flash light. The top of the piston should be dirty, and even be black which is normal. If it's washed clean that's a bad sign that coolant has been coming into the cylinder. If it's cylinder #1 then it's got some rot on the head, #'s 3 or #4 then it's a cracked head or has some rot on the head, or in some rare cases a badly warped head. If it's #6 it's almost always a warped head and needs to be shaved.
On the fuel problem you can start out by pulling the vacuum hose off of the fuel pressure regulator and plug off the hose with a golf tee. Then crank the engine over with the key and see if any fuel comes out of the vacuum tube on the regulator. If it does then it's defective and needs to be replaced before you start the engine. Right now they're not available new but I do have a few good used ones in stock. They will be available new eventually but who knows when. There are other things that can cause your excessive fuel consumption like injectors sticking open but looking at the piston tops and the spark plugs should point the finger for you. I do sell rebuilt injectors. The metal case is reused and everything else is new. Need any of these parts or more then contact me by phone or by e-mail. I don't monitor this site all the time but do give exclusive discounts to people that use this site. Good luck on figuring things out. Z man of Washington
 

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if there is a head gasket leak or cracked block or head allowing exhaust gases into the coolant, the blue will turn green or yellow VERY quickly. another indicator without the test kit is if the coolant just quickly overflows the rad, not cause its hot but because gases are getting into the system and pushing the coolant out.
 

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With respect, I'm not a fan of stop leaks for head gasket problems, and have very seldom found them to work. A shop can do a leak-down test or you can do the NAPA test mentioned above (although I'm not familiar with it.)
The one and only way to correctly fix a bad head gasket dependably is to pull the head, have it checked to make sure it's not warped, replace the head gasket and re-assemble correctly.
 

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Well as I agree removing the head is the best way, it seems to me the OP is trying to avoid that. This is simple. It’s a head gasket. You can test this and that, but I bet if you take off the radiator cap, turn on your heater so that the petcock valve is open, run the engine until it is at operating temperature and add the alumaseal it will work. Especially if there are no signs of water or coolant in the oil. This is an easy fix if you need to use your car until you can pull the engine apart, because that’s what you will have to do. It’s the head gasket. Unless the OP seriously overheated the engine, which wasn’t mentioned, it is not a warped head. Actually the more I think about it, a previous owner could have, and when the head is pulled they might find alumaseal already around the leak, and it has finally let go. The stuff works.
 

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And as far as the fuel problem. If the engine consumed 5 gallons of gas that fast I don’t believe it could run. As mentioned above, check the pressure. Disconnect the cold start injector after you start it. Does that change anything?
 
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