Hey all, new here. Picked up my Z a few days ago and am going through it top to bottom, Front to back.

I'm curious... I have an issue that at around 5k-5.5k the motor bogs in every gear, similar to Fuel Starvation. This happens regardless of how much "Mash" I have on the pedal, just straight up RPM related. I havent tried to hold the pedal to see if it clears or not, I just back off right when it happens.

No, I havent DVOM'd the fuel pump or checked line pressure yet (Planning to test everything thoroughly today) but I have verified that timing is at 10* BTDC, changed the plugs, Oil, Oil Filter, Air Filter...etc.

Motor is strong and functioning as expected up until that point. I can say that when I pulled the plugs that were in it, they read pretty white with no deposits. As far as I know (I may be wrong) that would indicate a lean mix. This boggles my mind because the car itself when running smells really rich.

Today I'm going to replace the Fuel Filter, see if I can do something to verify that the Vacuum Advance on the Dizzy is functioning properly, Check the Carbon Can (just for fun) and see what I can dig up on tesing the Fuel Pump.

Car lopes slightly on idle, nothing I would be concerned with and more than likely just a collision of exhaust pulses (lope heard via exhaust, motor smooth). Idles and runs smooth with no odd vibration or anything under regular load.

I'm relatively certain that testing the entire delivery system would yield the answer but I wondering if anbyone here is familiar with this issue or has any advice regarding things I may not think of to check OR advice as to the testing route based on experience and not the actual Service Manual.

N/A L28E 1977 Datsun 280Z Coupe

Thanks

 

I would check your AFM. I had an issue where the carbon contact was worn so it was not sending the right signals to the ECU. I moved the board 0.5 mm down on the existing screws and it fixed the problem. Mine was happening at 16-1800 RPM, not 5k, so it may not be at all related, but sounds similar to my mess.

 

Thanks, I'll check that out.