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Hello guys! I'm new to this forum and recently new to the datsun world :)  I purchased a 1981 280zx datsun that has been sitting outside a barn for about 4-6 years and since it still had the engine I decided to see if I can get it running before I even consider swapping the same l28e or if I get lucky the l28et. The first things I did was:

  1. change the oil,
  2. replace the fuel filter 
  3. flush tank and replace gasoline (regular)
  4.  replaced battery with terminals
  5. flush and replace coolant,
  6. spark plug wires (all in correct firing order)
  7. change ngk spark plugs (gaped .42 and added oil in each cylinder for lubrication)

I cranked it with no luck, I heard the oil pump running loudly but decided to use starter fluid. Once started fluid was sprayed and the engine was cranked and the engine started and was running on starter fluid so my next steps were:

  1. clean injectors
  2. clean fuel rail
  3.  replace o rings and insulation 

I cranked it again without starter fluid and it only cranked but didnt start. So I did a compression test and numbers were 140, 145, 145, 140,145, 155 so compression is pretty good being that 180psi is like new. I removed the fuel return line and cranked the engine and gasoline came rushing out, I tested the spark and its a blue with white tint, engine sounds like it wants to start so timing is good (?), exhaust smells like gasoline and has pulses, and it still doesnt want to start. Each time i remove the spark plugs after attempting to start it, i can see a little wetness on the tip and it smells like gas. It started once with starter fluid but now it just doesnt want to even with it.  What do you guys think can be the problem? thank you!

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Fuel pressure gauge before doing anything else, if you have not already study the FSM for what to look for on pressure.

Corrosion is a big problem on a lot of the connectors to the injectors and sensors, grounds and fuse links. Clean them all.

check for air leaks, EFI does not like unmetered air. Sensors tend to drift. The FSM has a good diagnosis section to point where to look.

I would listen for the injectors to be clicking.

 

Could be the injectors, you could pull them up, leave everything connected and have someone try starting, observe the spray.

What insulation are you referring to in 3?

 

 

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2 hours ago, Dave WM said:

Fuel pressure gauge before doing anything else, if you have not already study the FSM for what to look for on pressure.

Corrosion is a big problem on a lot of the connectors to the injectors and sensors, grounds and fuse links. Clean them all.

check for air leaks, EFI does not like unmetered air. Sensors tend to drift. The FSM has a good diagnosis section to point where to look.

I would listen for the injectors to be clicking.

 

Could be the injectors, you could pull them up, leave everything connected and have someone try starting, observe the spray.

What insulation are you referring to in 3?

 

 

What do you mean by the FSM? I have not checked the FSM on the l28e to check for fuel pressure but I thought it was getting enough fluid since it wasn't starting on starter fluid  

That is a really good idea, I'll do that! 

Injectors work for sure because when I cleaned them, I grounded them to a 12v battery and power and attached them to a pressurized hose with injector cleaner and they made the clicking noise and sprayed straight 

i have not sprayed them with the wiring harness though so I could give it a try 

injector insulation as like the bushing that go around it and on the head when you put Injectors in

 

thank you!

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1 hour ago, Eric280zx said:

Also, the spark plugs seem to be getting fuel on them 

Might be flooding due to disconnected or broken coolant temperature sensor.  And somebody parked it beside the barn for a reason.

The 1980 EFI Manual is probably about the same for 1981.  Might use it to at least get familiar with the parts.

http://www.classiczcars.com/files/category/14-280zx/

http://www.classiczcars.com/files/category/4-manuals/  1980 "EFI Book"

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If it will help to determine the problem, i am also missing two fuses on the interior panel of the car, it is # 7 and #8 and haven't determined what they are for. I still have to clean any corroded wires, sensor plugs, check for air leaks with the EFI, check the coolant sensor, and check fuel pressure. I'll post up my results after doing all this 

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So I did everything with still no luck. I did check the oil and I noticed it's wayyy over the high level and it smells like gas. I took a quart of oil out and it's more of a liquid substance now with a smell of gas. I think my problem is a leaking fuel Injector. What do you guys think? If so, is it the injector or harness? 

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I would take a screwdriver handle and tap on the injectors to free up a stuck magnet. I bought a motor with a bad carbeurator and the oil was half gasoline from the stuck carb float dumping all that fuel on the head then it drops down the front cover/timing chain hole straight into the oil pan. The plus side, if you could say that was the gas had washed the head/valve train to look like brand new. But it's not good especially on the valve seals.

You can get a piece of hose to use as a stethoscope to hear the injectors clicking. Whichever one doesn't click is stuck, tap it until it starts clicking hopefully or you may have to replace it.

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don't forget to check the cold start injector.  Pull it out of the manifold and look to see if its leaking, in warm weather (over 70f) it should not spray, and it should only spray when the key is in the "Start" position even when its cold. Often times people goof up the bullet connections for the temp sensor for the EFI and the cold start thermotime swtich, make sure they are correct.

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1 hour ago, Eric280zx said:

So I did everything with still no luck. I did check the oil and I noticed it's wayyy over the high level and it smells like gas. I took a quart of oil out and it's more of a liquid substance now with a smell of gas. I think my problem is a leaking fuel Injector. What do you guys think? If so, is it the injector or harness? 

The injectors get power as soon as you turn the key On.  So any short to ground on the wires going back to the ECU would open them.  A pinched or abraded wire for example.  But a short should show up in your testing at the ECU, as a voltage drop, less than battery voltage measured at the injector pins.  You might also hear them click when your turn the key on although the BCDD clicks also.

The CSV should only get power when the key is at Start.  So it's possible that it would flood the engine, but the odds of pumping a quart of gas in to the engine through shorted injectors, by sitting with the key On, thinking, seems more likely.

I filled a chevy crankcase with gasoline after I put a friend's carb on the car and tried to start it.  Turns out he had got it from someone else and they had removed the float valve.  

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42 minutes ago, siteunseen said:

I would take a screwdriver handle and tap on the injectors to free up a stuck magnet. I bought a motor with a bad carbeurator and the oil was half gasoline from the stuck carb float dumping all that fuel on the head then it drops down the front cover/timing chain hole straight into the oil pan. The plus side, if you could say that was the gas had washed the head/valve train to look like brand new. But it's not good especially on the valve seals.

You can get a piece of hose to use as a stethoscope to hear the injectors clicking. Whichever one doesn't click is stuck, tap it until it starts clicking hopefully or you may have to replace it.

I have the fuel rail removed right now with everything else connected and I'm going to switch the key just so it starts priming, got the idea from Dave WM. I'll observe if gas is leaking out, should I expect very little or none at all? If it's an obvious leak I'll tap it in hopes that it stops. 

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37 minutes ago, Dave WM said:

don't forget to check the cold start injector.  Pull it out of the manifold and look to see if its leaking, in warm weather (over 70f) it should not spray, and it should only spray when the key is in the "Start" position even when its cold. Often times people goof up the bullet connections for the temp sensor for the EFI and the cold start thermotime swtich, make sure they are correct.

Ive heard of people talking about the cold start injector but never gave it any thought, I'll locate the injector and see if it sprays, it shouldn't pray like you said because where I am it's 78 degrees, then I'll have a look at the connections to see if it's correct. 

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"I have the fuel rail removed right now with everything else connected and I'm going to switch the key just so it starts priming, got the idea from Dave WM. "

 

That's a good idea.  Is the CSV out too?  Watch all seven.

There's no prime pulse on 1981 I think.  That came later and even then it often doesn't work.  Disconnect the starter solenoid wire, and turn the key to Start.  The engine won't turn but the pump will get power.

Edited by Zed Head

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40 minutes ago, Zed Head said:

"I have the fuel rail removed right now with everything else connected and I'm going to switch the key just so it starts priming, got the idea from Dave WM. "

 

That's a good idea.  Is the CSV out too?  Watch all seven.

There's no prime pulse on 1981 I think.  That came later and even then it often doesn't work.  Disconnect the starter solenoid wire, and turn the key to Start.  The engine won't turn but the pump will get power.

So I primed the engine and I can hear the presssure regulator working and no leaks on all seven. My outside temperature is 73 degrees and when I cranked it the only one that sprayed was the cold start valve ( cold start injector). I'm going to do it without he starter, I didn't read that till now 

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okay so, I disconnected the starter and when I started it, none of the injectors sprayed but the csv ( cold start injector) did and it sprayed for over 15 seconds and it would've easily kept going. Is it supposed to do that or is that what's my problem? Could be the temp sensor misguiding the csv 

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It's supposed to spray until the thermotime switch heats up and opens the circuit.  The engine should have started on the CSV fuel.  Maybe you have bad fuel.

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7 minutes ago, Zed Head said:

It's supposed to spray until the thermotime switch heats up and opens the circuit.  The engine should have started on the CSV fuel.  Maybe you have bad fuel.

I've cleaned the fuel tank, added a new fuel  filter, cleaned rail, and injectors. Then I put 5 gallons of regular gasoline. Then every time I crank it, spark plugs get wet with fuel. With the test I did, none of the injectors sprayed just the csv. Other forums say it should've only sprayed for 2-12 seconds, could my thermotime switch be bad? 

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Something doesn't make sense. You know it runs on starter fluid and the injectors are not firing. 

Have you confirmed The fuel pressure off the rail yet? Also have you confirmed the fusible links by the batter for the EFI is good?

I'm really confused how your getting gas in the oil and it won't start, but will start with starting fluid. If it was flooding it wouldn't run on starter fluid and all the extra gas. 

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2 hours ago, JSM said:

Something doesn't make sense. You know it runs on starter fluid and the injectors are not firing. 

Have you confirmed The fuel pressure off the rail yet? Also have you confirmed the fusible links by the batter for the EFI is good?

I'm really confused how your getting gas in the oil and it won't start, but will start with starting fluid. If it was flooding it wouldn't run on starter fluid and all the extra gas. 

The engine ran for 5 seconds the very first crank by simply adding starter fluid (engine was completely dry) so once this happened I did some things to the fuel, spark, and compression to all be good but it seems like every time I crank it afterwords, it floods and spark plugs get wet and the possibly faulty or misinformed CSV is just pouring gas making its way through the timing chain, crankcase, and oil pan. I have not checked the fuel pressure since I am already getting too much fuel and didn't think it'd be a problem but if it can help determine the problem I can definitely do it. Where is the fuse from the battery to the EFI? 

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You can always cap of the CSV for the time being. Slide a bolt into the hose leading to it. 

The fusible links are in a little box next to the battery. 

 

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do what JSM said, disconnect the CSV hose and cap it for now. should not be firing at all unless its cold where you are. At lest you will stop flooding the crankcase with gas (I would drain the oil and refill again until you figure this out, no reason to destroy the bearings in case is starts from gas thinned oil). you need to get to a point where NO fuel is spraying with the key in start and the starter solenoid disconnected. You should just see the pressure jump to 36 psi, then release the key from start and it should stay there at least for several minutes. How well it holds pressure will tell you if you are leaking fuel OR the fuel pump check valve could be bad. Regardless, get that working before moving on. Its best to resolve one system at a time rather than jumping from one magic bullet to another. Don't start replacing parts unless you know they are bad, doing so only adds more variables that can cause it to be harder to figure out what is wrong.

Next you need to review the FSM and sort out the EFI injectors. Grounds and fuse links (including the main  positive one right of the battery that feed the ECU harness). Don't be confused by the color of wires Red and Black do not always relate to positive and negative on the harness. Think that was an issue for another poster recently. You need to check voltages AT the disconnected 36 pin connecter. This assume the fuel injectors are not the problem (gummed up) a noid light would be a test to see if they are getting pulses.

the only shot gun approach that you can consider is a check of all grounds and connectors (bullet and EV1 style on the sensors and injectors). these corrode and can give all kinds of problems, not easy to find using the typical voltage check due to the low currents of the test equipment (typical of DMM's). A  very corroded contact will not drop voltage when measured with a high impedance voltmeter, but in actual use when current loads are much higher the resistance cause by the corrosion can have a large voltage drop.

Again make sure the thermotime and the temp sensor wires have not been switched around they have the same connector ends (bullet) and can be reverse causing all kinds of issues. You can tell for sure by simply tracing from the theromtime (large on the thermostat) wire harness, trace to where it connects back to the cold start valve. its in a shared harness with the temp sensor but you can tell which is which by careful observation. the Temp sensor is the smaller of the two things that screw into the from of thermostat. It to is frequently a problem, but its easy to test and is part of the 36 pin check out items in the FSM. Its a simple thermistor type device so the test will include comparing the water temp (or ambient if the car is cold) to a chart where there resistance changes with temp. When these go you tend to have rough running due to too rich as they typically drift up in resistance. However again this is just conjecture as to what could be wrong, test things before replacing. And don't overlook the possibility of corrosion or wiring errors (which is why I suggest the shot gun approach on the cleaning of connections).

One last thing to note, the wire harness is well past its expected life span, with that in mind exercise care when connecting/disconnecting/flexing etc... its easy to break wires, just adding to user caused problems that then need to be sorted.  If you see a LOT of green corrosion on the pins of the connectors its likely that you will need to do some extensive surgery to excise the problem wires as that green has a way of working up a copper wire. Just keep this in mind when looking over stuff.

 

 

 

 

 

 

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9 hours ago, Dave WM said:

do what JSM said, disconnect the CSV hose and cap it for now. should not be firing at all unless its cold where you are. At lest you will stop flooding the crankcase with gas (I would drain the oil and refill again until you figure this out, no reason to destroy the bearings in case is starts from gas thinned oil). you need to get to a point where NO fuel is spraying with the key in start and the starter solenoid disconnected. You should just see the pressure jump to 36 psi, then release the key from start and it should stay there at least for several minutes. How well it holds pressure will tell you if you are leaking fuel OR the fuel pump check valve could be bad. Regardless, get that working before moving on. Its best to resolve one system at a time rather than jumping from one magic bullet to another. Don't start replacing parts unless you know they are bad, doing so only adds more variables that can cause it to be harder to figure out what is wrong.

Next you need to review the FSM and sort out the EFI injectors. Grounds and fuse links (including the main  positive one right of the battery that feed the ECU harness). Don't be confused by the color of wires Red and Black do not always relate to positive and negative on the harness. Think that was an issue for another poster recently. You need to check voltages AT the disconnected 36 pin connecter. This assume the fuel injectors are not the problem (gummed up) a noid light would be a test to see if they are getting pulses.

the only shot gun approach that you can consider is a check of all grounds and connectors (bullet and EV1 style on the sensors and injectors). these corrode and can give all kinds of problems, not easy to find using the typical voltage check due to the low currents of the test equipment (typical of DMM's). A  very corroded contact will not drop voltage when measured with a high impedance voltmeter, but in actual use when current loads are much higher the resistance cause by the corrosion can have a large voltage drop.

Again make sure the thermotime and the temp sensor wires have not been switched around they have the same connector ends (bullet) and can be reverse causing all kinds of issues. You can tell for sure by simply tracing from the theromtime (large on the thermostat) wire harness, trace to where it connects back to the cold start valve. its in a shared harness with the temp sensor but you can tell which is which by careful observation. the Temp sensor is the smaller of the two things that screw into the from of thermostat. It to is frequently a problem, but its easy to test and is part of the 36 pin check out items in the FSM. Its a simple thermistor type device so the test will include comparing the water temp (or ambient if the car is cold) to a chart where there resistance changes with temp. When these go you tend to have rough running due to too rich as they typically drift up in resistance. However again this is just conjecture as to what could be wrong, test things before replacing. And don't overlook the possibility of corrosion or wiring errors (which is why I suggest the shot gun approach on the cleaning of connections).

One last thing to note, the wire harness is well past its expected life span, with that in mind exercise care when connecting/disconnecting/flexing etc... its easy to break wires, just adding to user caused problems that then need to be sorted.  If you see a LOT of green corrosion on the pins of the connectors its likely that you will need to do some extensive surgery to excise the problem wires as that green has a way of working up a copper wire. Just keep this in mind when looking over stuff.

 

 

 

 

 

 

Very detailed information, thank! So right now I checked fuel pressure and at prime it's at 40psi and starting is 38psi but when I release the key the psi slowly go back down and doesn't stay like Dave said it should. No fuel is spraying, all seven injections didn't drip, so up next is the fuel pump check valve that could be bad. Where is it located, I'm going to replace this part and see if it maintains the 36psi and not just drop 

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