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greylandimports

240z carb sync ignition timing disaster NEED HELP :(

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When plugs are soaked with fuel, they basically don't do anything... while its running, place the timing light sensor on each lead and that will tell you which one is / isn't firing. Or you can just carefully remove each lead off each plug (without getting electrocuted!!!) and listen to the engine and if you don't notice a change, that plug isn't firing. Reset your carby fuel settings back to "default" and start again.. Go back to the basics.. Make sure there is fuel, spark and air! and triple check the timing..

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maybe you would be better off reading the factory service manuals, available on this site: http://carfiche.com/manuals023/cars/ the instructions they give to tune the carbs are much the same as the youtube video posted before.

 

timing is dead easy to get in the ballpark. take the rocker cover and spin the crank pulley over clockwise. pay attention to cylinder 1, the one at the front. when the exhaust rocker is almost closed and the intake is just opening, this is near enough to TDC. pop the top off the dizzy, take note of where the rotor is pointing. undo the dizzy retaining bolt so you can turn it. hold the cap loosly over for reference and turn the dizzy so that one of the 'towers' lines up with the rotor. you have now set the dizzy to ~TDC, good enough to get it running. do the bolt back up so you cant move the dizzy, lock the cap on, and stick spark plug 1 to the tower you lined up with the rotor. now put the rest of the plugs on in the correct order. i believe for the L engines, this is anticlockwise direction!

 

that is it for timing, easy as. next step would be get the carby running sweet, but not worry about the idle so much. just fire it up and let it run whereever. focus on adjusting the flow through the carbies and getting the mixtures good. then go back and set the timing. when that is good, adjust the idle on the carbies, and you should be done.

 

one thing that occured to me before is when you checked the timing, did you disconnect the vacuum advance. vac advance moves the spark 20+ degrees advance, ie the timing marker would move anti-clockwise. when setting the inital timing, you set it with the vac disconnected, because you set it ~10-15 advance (not sure on the datsun specifics here, read the service manual). also, my engine has 2 lots of timing markers on it, i presume the ones to use are located on the same side as the dizzy.

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Well, I got a compression tester in the mail and my compression is good. When I hook up the timing light, the light doesn't flash on the cylinders that are not firing. I know that 2,3,5 are not firing. When I pull the plugs on these cylinders nothing happens to the idle of the engine but when if I pull 1,4,6 the engine dies. The plugs on 2,3,5 are wet when I pull them, and 1,4,6 are dry. There is some black discharge leaking out of the plug holes too but I think I didnt have them tight enough. I made sure all the plugs had good connections and I put the plugged in spark plug next to a body ground and it sparked. What else can I check?

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Also,

I was reading other posts on here and I was putting a lot of fuel through the carbs. I turned the knobs under the carbs two full turns out. Could this cause a problem?? On only three cylinders??

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God damn it. The gas is bad. I was rereading the post and someone suggested it before. Draining it now. Thank you for the great tips!!!! Does this make sense to everyone else??? I think its my big problem. Now how do I go about flushing the system?

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i would pop the fuel line off the pump and using compressed air blow the fuel back down to the tank. do this with the fuel cap off the tank, so the air can get out.

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i would pop the fuel line off the pump and using compressed air blow the fuel back down to the tank. do this with the fuel cap off the tank, so the air can get out.

 

u would be putting any crap back in the tank, better to blow out fuel lines from the tank forward

The gas is bad. I was rereading the post and someone suggested it before. Draining it now. Thank you for the great tips!!!! Does this make sense to everyone else??? I think its my big problem. Now how do I go about flushing the system?

if the fuel is bad, wouldnt both carbies be effected and all plugs would be the same?

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