71 240 w/76 l28

[pimpjester]

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Join Date: Jul 2007

Location: Joplin, Missouri

Posts: 35

Question 71' 240z

Hi first off I ate a rod bearing on my L24 so i pulled it out and dropped in a L28 from a 280z parts car motor ran not good then bad injectors but it would still drive. I installed all my stuff off of my 71' 240 onto it, I have a 76' electronic ignition new wires and good plugs, also installed my headers, aswell as my dual weber carbs did all that turn the key and it starts not smooth like my old one but starts.

The problem is if u give it any gas at all it stumbles and tries to die, half the time it will die but start right back up at the turn of the key.

I have checked my timing and i am confused i set distributor at the 11 o'clock it calls in chilton check rotor and its at the #1 spot like it should be. My father was helping me out and he was reving it up it seemed to get better so we continued tweaking it to get it smooth and it didn't help same thing.

I have good fuel, fuel pressure, plugs,wires, spark, and compression.

What I don't have is a freaking clue.

Old motor ran like a top smooth and strong so i know parts are good that i have put on but is there a timing issue that the l28 has that changes from efi to carbs.

All vacuum lines are the same and i checked em.

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[Zedyone_kenobi]

honestly, it sounds like your leaning out. Your carbs may need to be richened up a bit to accommodate the larger displacement. It starts and idles fine but the second you give it gas it stumbles. Sounds like an accelerator pump issue, or jetting.

How do the plugs look? The tail pipe? I would set the timing per the factory spec and then try to only adjust one thing at a time. Your lucky that you can get it to idle, its much easier to troubleshoot a running engine.

Personally I would start with checking to see if your getting the right amount of fuel off idle.

[240ZX]

Just as a precaution, you might want to check the condition of the advance mechanism on the L28 distributor....they are known to fail with age.

Tom