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Motor: I have a 1976 datsun 280z I just swapped in a l28et motor. The swapped motor was from junkyard 1980 280zx automatic that has not ran in all most a year. I am using the stock s130 ECU.

 

Fuel: I am using the stock fuel pump from the 1976 280z and just got brand new 310 CC injectors. The injectors are pulsing and I am getting good fuel pressure.

 

Spark: I am getting good spark I replaced the plugs, dizzy cap, rotor and coil.

 

Timing: The motor cranks and makes some pops but does not turn over. I have not touched the mechanical timing. I have the firing order correct (153624) counter clock wise. My dizzy does not have the CAS in it the CAS is located on the crank pulley. I have not checked to see where my dizzy shaft is when the motor is at TDC (I do not think this would matter because I have not touch the internals of this engine)

 

Air: I've tested the AFM it is 217 ohm the FSM says it is supposed to be 280 to 400 ohms. my compression is 6 [95] 5 [95] 4 [100] 3 [100] 2 [95] 1[96] I am not sure if this is low enough to make my motor not start. 

 

conclusion: I was wondering if either my compression, my AFM would be stopping my motor from running or if I have over looked something. I would like some feed back before I either get a new AFM or start ripping apart my motor to look into the compression. Thanks in advance for any feed back  :D

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Posted (edited)

If you're getting spark, the ECU is getting RPM information from the CAS.  DON'T touch the AFM internals (although in reality, it would be unusual if someone hasn't already...) Do make sure the AFM electrical connections are clean and have continuity back to the ECU.  However, I'd say if you have spark and fuel - better check timing...  The 310's are going to make that engine run rich.  Make sure your spark plugs are clean (new preferably).

 

Start from the beginning and check the mechanical timing.  You can't make any assumptions with these old engines - you don't know whose hands have been on them.  Having said that, 90% of the problems with these early EFI (ECCS) engines are ELECTRICAL in nature.  Make sure your sensors and associated wiring are working properly, have CLEAN and deoxidized connections, and that their wiring has continuity back to the ECU.  

 

Be sure you have the Factory Service Manual for 1981 with the Turbo Supplement (not a mistake, the L28ET with crank mounted CAS came in the 1981 280ZX Turbo model) and follow the trouble-shooting steps.  There's a section that shows how to do all that without the "Analyzer".  You just need a multimeter. 

Edited by cgsheen

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Timing: The motor cranks and makes some pops but does not turn over. 

 

Your cylinder pressure numbers look okay for a turbo engine.  They're consistent across all-six which is a better indicator than the actual number.

 

Then engine does "turn over", but does not fire.  

 

Try starting fluid in the intake manifold.  But check your spark plugs first to see if they're wet to be sure.  If they're dry, the starting fluid should start the engine, but it might then die.  Not enough fuel from the system.  If they're wet you'll know to focus on too much fuel.

 

Check as much as you can at the ECCS plug with a meter as cgsheen suggests.  That will tell you if the CHTS is properly connected, HowlerMonkey's suggestion.

 

Beside that, when you're done, your 310cc injectors will spray 17% too much fuel and the engine will run rich. 

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Update: I got brand new spark plugs in and tried to run the motor with some starting fluid. The motor still did not start. I checked the plugs right after and they were dry. I also clean all the connections to all the seniors. I followed the steps in the FSM to check the air temperate senior and it was not able to get a reading with the multi meter. I did the same thing with the cylinder head temp sensor and was not able to get a omhs reading either (I checked from the plugs to the ECU and from the actual seniors themselves). The Throttle valve switch checked out just fine. I have not be able to check the mechanical timing yet.

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Posted (edited)

 

Spark: I am getting good spark I replaced the plugs, dizzy cap, rotor and coil.

 

Timing: The motor cranks and makes some pops but does not turn over. I have not touched the mechanical timing. I have the firing order correct (153624) counter clock wise. 

 

 

Update: I got brand new spark plugs in and tried to run the motor with some starting fluid. The motor still did not start. I checked the plugs right after and they were dry.

 

Either the spark is not really strong enough, or your timing is off.  You might have the firing order correct but maybe #1 is not in the right place.  Many of these old engines have their oil pump drives incorrectly installed and plug wires adjusted to make it work,  then when people do a tuneup they put them back to the way they should be, and they don't work anymore.

Edited by NewZed

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Did you squirt the starting fluid in to the intake manifold or in to the air filter?  It needs to go directly in to the intake manifold through one of the small vacuum ports.

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Posted (edited)

 I followed the steps in the FSM to check the air temperate senior and it was not able to get a reading with the multi meter. I did the same thing with the cylinder head temp sensor and was not able to get a omhs reading either (I checked from the plugs to the ECU and from the actual seniors themselves). 

 

Eventually it will be important that those sensors are working properly.  You'll be able to buy a new CHTS and replace if necessary.  The intake air temp sensor in the AFM might be a different story...

 

It's sounding more like timing.

Edited by cgsheen

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Update: I got the motor to run for about 5 seconds but it died. I used 536241 for the plugs on my distributor cap. Ill pull the oil pump sometime this weekend and install it correctly. After the motor started it seized up and did not want to crank. I took a 27 mm socket to the crank pulley but it did not want to move at all. I unplugged all of the spark plugs and was able to un-seize the motor with the spark plugs out. I tried to start it again, it ran for a few seconds then died and seized up. Any ideas?

 

 

a video of it running for a few seconds before it died:

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Oil pump installed correctly? What does that mean?

 

If the motor is seizing, your not likely getting oil pressure. You may have a bad oil pump or plugged pick up screen. Did you have the oil pan off before you installed the motor in the car?

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Oil pump installed correctly? What does that mean?

 

If the motor is seizing, your not likely getting oil pressure. You may have a bad oil pump or plugged pick up screen. Did you have the oil pan off before you installed the motor in the car?

Sorry I should have clarified. Install the oil pump correctly while my motor is a TDC to set the timing properly. I have not had the oil pan off. I did change the oil and it looked decent but that does not mean that the screen is not getting plugged.

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There's too much guessing going on.  You can check the valve train for oil to see if the pump is pumping oil.  The engine should never "lock up".  Are you sure that the battery is not just dead from cranking?  Did any fluids come out of the spark plug holes when you finally got it to spin?  The pickup screen is not going to be so clogged that engine seizes from lack of lubrication.

 

Get a friend who has a bit more experience with engines.  You're getting stuck on super-simple stuff.

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Remove the valve cover and spin the motor with the starter, spark plugs out.  If you see oil from the cam shaft lube holes you'll know that the oil pump is working.  You'll want to do that before you remove it anyway, because if it's bad you'll need to replace it.

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There's too much guessing going on.  You can check the valve train for oil to see if the pump is pumping oil.  The engine should never "lock up".  Are you sure that the battery is not just dead from cranking?  Did any fluids come out of the spark plug holes when you finally got it to spin?  The pickup screen is not going to be so clogged that engine seizes from lack of lubrication.

 

Get a friend who has a bit more experience with engines.  You're getting stuck on super-simple stuff.

I had the battery tested it was fine and it was charging over night so it was fully charged. I know its also not the battery because if it was i could still be able to turn over the motor with a socket on the crank pulley. No fluids came out of the spark plugs.

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 After the motor started it seized up and did not want to crank. I took a 27 mm socket to the crank pulley but it did not want to move at all. I unplugged all of the spark plugs and was able to un-seize the motor with the spark plugs out. I tried to start it again, it ran for a few seconds then died and seized up. 

 

So the engine has seized up twice?  Might be the reason that car was in the junk yard.

 

I'd spin the engine with the valve cover off and plugs out, using the starter, if it was mine.  Less stress on the parts and you can hear any odd mechanical noises.  You'll drip some oil down the side of the engine but the late model reduction starters don't spin the engine that fast so it's not so messy.  Watch oil flow, listen for noises, get things lubed up.

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Update: I GOT IT RUNNING!!!!! I put some oil in to the cylinders that unsiezed the motor and allowed it to start. It smoked for a bit which is to be expected. Just need to play with the timing to get it to ideal. Thank you all for the help! 

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